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Fred Drake 1998-02-27 05:23:37 +00:00
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Doc/lib/libprofile.tex
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@ -39,7 +39,7 @@ As a result, it is probably clumsy code, but I don't know for sure yet
so that profiling would be a reasonable thing to do. I tried not to so that profiling would be a reasonable thing to do. I tried not to
repeat code fragments, but I'm sure I did some stuff in really awkward repeat code fragments, but I'm sure I did some stuff in really awkward
ways at times. Please send suggestions for improvements to: ways at times. Please send suggestions for improvements to:
\code{jar@netscape.com}. I won't promise \emph{any} support. ...but \email{jar@netscape.com}. I won't promise \emph{any} support. ...but
I'd appreciate the feedback. I'd appreciate the feedback.
@ -49,10 +49,12 @@ I'd appreciate the feedback.
A \dfn{profiler} is a program that describes the run time performance A \dfn{profiler} is a program that describes the run time performance
of a program, providing a variety of statistics. This documentation of a program, providing a variety of statistics. This documentation
describes the profiler functionality provided in the modules describes the profiler functionality provided in the modules
\code{profile} and \code{pstats.} This profiler provides \module{profile} and \module{pstats}. This profiler provides
\dfn{deterministic profiling} of any Python programs. It also \dfn{deterministic profiling} of any Python programs. It also
provides a series of report generation tools to allow users to rapidly provides a series of report generation tools to allow users to rapidly
examine the results of a profile operation. examine the results of a profile operation.
\index{deterministic profiling}
\index{profiling, deterministic}
\section{How Is This Profiler Different From The Old Profiler?} \section{How Is This Profiler Different From The Old Profiler?}
@ -81,7 +83,7 @@ profiler \emph{during} profiling (and charged to user's code!).
\item[Speed increased:] \item[Speed increased:]
Overhead CPU cost was reduced by more than a factor of two (perhaps a Overhead CPU cost was reduced by more than a factor of two (perhaps a
factor of five), lightweight profiler module is all that must be factor of five), lightweight profiler module is all that must be
loaded, and the report generating module (\code{pstats}) is not needed loaded, and the report generating module (\module{pstats}) is not needed
during profiling. during profiling.
\item[Recursive functions support:] \item[Recursive functions support:]
@ -116,7 +118,7 @@ The above action would cause \samp{foo()} to be run, and a series of
informative lines (the profile) to be printed. The above approach is informative lines (the profile) to be printed. The above approach is
most useful when working with the interpreter. If you would like to most useful when working with the interpreter. If you would like to
save the results of a profile into a file for later examination, you save the results of a profile into a file for later examination, you
can supply a file name as the second argument to the \code{run()} can supply a file name as the second argument to the \function{run()}
function: function:
\begin{verbatim} \begin{verbatim}
@ -124,12 +126,15 @@ import profile
profile.run("foo()", 'fooprof') profile.run("foo()", 'fooprof')
\end{verbatim} \end{verbatim}
% %
\code{profile.py} can also be invoked as The file \file{profile.py} can also be invoked as
a script to profile another script. For example: a script to profile another script. For example:
\code{python} \code{/usr/local/lib/python1.4/profile.py myscript.py}
\begin{verbatim}
python /usr/local/lib/python1.4/profile.py myscript.py
\end{verbatim}
When you wish to review the profile, you should use the methods in the When you wish to review the profile, you should use the methods in the
\code{pstats} module. Typically you would load the statistics data as \module{pstats} module. Typically you would load the statistics data as
follows: follows:
\begin{verbatim} \begin{verbatim}
@ -137,10 +142,10 @@ import pstats
p = pstats.Stats('fooprof') p = pstats.Stats('fooprof')
\end{verbatim} \end{verbatim}
% %
The class \code{Stats} (the above code just created an instance of The class \class{Stats} (the above code just created an instance of
this class) has a variety of methods for manipulating and printing the this class) has a variety of methods for manipulating and printing the
data that was just read into \samp{p}. When you ran data that was just read into \samp{p}. When you ran
\code{profile.run()} above, what was printed was the result of three \function{profile.run()} above, what was printed was the result of three
method calls: method calls:
\begin{verbatim} \begin{verbatim}
@ -188,7 +193,7 @@ p.sort_stats('file').print_stats('__init__')
% %
This will sort all the statistics by file name, and then print out This will sort all the statistics by file name, and then print out
statistics for only the class init methods ('cause they are spelled statistics for only the class init methods ('cause they are spelled
with \code{__init__} in them). As one final example, you could try: with \samp{__init__} in them). As one final example, you could try:
\begin{verbatim} \begin{verbatim}
p.sort_stats('time', 'cum').print_stats(.5, 'init') p.sort_stats('time', 'cum').print_stats(.5, 'init')
@ -206,7 +211,7 @@ now (\samp{p} is still sorted according to the last criteria) do:
\begin{verbatim} \begin{verbatim}
p.print_callers(.5, 'init') p.print_callers(.5, 'init')
\end{verbatim} \end{verbatim}
%
and you would get a list of callers for each of the listed functions. and you would get a list of callers for each of the listed functions.
If you want more functionality, you're going to have to read the If you want more functionality, you're going to have to read the
@ -252,12 +257,12 @@ of algorithms to be directly compared to iterative implementations.
\section{Reference Manual} \section{Reference Manual}
\setindexsubitem{(profiler function)} \setindexsubitem{(in module profile)}
The primary entry point for the profiler is the global function The primary entry point for the profiler is the global function
\code{profile.run()}. It is typically used to create any profile \function{profile.run()}. It is typically used to create any profile
information. The reports are formatted and printed using methods of information. The reports are formatted and printed using methods of
the class \code{pstats.Stats}. The following is a description of all the class \class{pstats.Stats}. The following is a description of all
of these standard entry points and functions. For a more in-depth of these standard entry points and functions. For a more in-depth
view of some of the code, consider reading the later section on view of some of the code, consider reading the later section on
Profiler Extensions, which includes discussion of how to derive Profiler Extensions, which includes discussion of how to derive
@ -267,8 +272,8 @@ code for these modules.
\begin{funcdesc}{profile.run}{string\optional{\, filename\optional{\, ...}}} \begin{funcdesc}{profile.run}{string\optional{\, filename\optional{\, ...}}}
This function takes a single argument that has can be passed to the This function takes a single argument that has can be passed to the
\code{exec} statement, and an optional file name. In all cases this \keyword{exec} statement, and an optional file name. In all cases this
routine attempts to \code{exec} its first argument, and gather profiling routine attempts to \keyword{exec} its first argument, and gather profiling
statistics from the execution. If no file name is present, then this statistics from the execution. If no file name is present, then this
function automatically prints a simple profiling report, sorted by the function automatically prints a simple profiling report, sorted by the
standard name string (file/line/function-name) that is presented in standard name string (file/line/function-name) that is presented in
@ -328,23 +333,28 @@ printed.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{pstats.Stats}{filename\optional{\, ...}} Analysis of the profiler data is done using this class from the
\module{pstats} module:
\setindexsubitem{(in module pstats)}
\begin{classdesc}{Stats}{filename\optional{\, ...}}
This class constructor creates an instance of a ``statistics object'' This class constructor creates an instance of a ``statistics object''
from a \var{filename} (or set of filenames). \code{Stats} objects are from a \var{filename} (or set of filenames). \class{Stats} objects are
manipulated by methods, in order to print useful reports. manipulated by methods, in order to print useful reports.
The file selected by the above constructor must have been created by The file selected by the above constructor must have been created by
the corresponding version of \code{profile}. To be specific, there is the corresponding version of \module{profile}. To be specific, there is
\emph{NO} file compatibility guaranteed with future versions of this \emph{no} file compatibility guaranteed with future versions of this
profiler, and there is no compatibility with files produced by other profiler, and there is no compatibility with files produced by other
profilers (e.g., the old system profiler). profilers (e.g., the old system profiler).
If several files are provided, all the statistics for identical If several files are provided, all the statistics for identical
functions will be coalesced, so that an overall view of several functions will be coalesced, so that an overall view of several
processes can be considered in a single report. If additional files processes can be considered in a single report. If additional files
need to be combined with data in an existing \code{Stats} object, the need to be combined with data in an existing \class{Stats} object, the
\code{add()} method can be used. \method{add()} method can be used.
\end{funcdesc} \end{classdesc}
\subsection{The \sectcode{Stats} Class} \subsection{The \sectcode{Stats} Class}
@ -352,37 +362,38 @@ need to be combined with data in an existing \code{Stats} object, the
\setindexsubitem{(Stats method)} \setindexsubitem{(Stats method)}
\begin{funcdesc}{strip_dirs}{} \begin{funcdesc}{strip_dirs}{}
This method for the \code{Stats} class removes all leading path information This method for the \class{Stats} class removes all leading path
from file names. It is very useful in reducing the size of the information from file names. It is very useful in reducing the size
printout to fit within (close to) 80 columns. This method modifies of the printout to fit within (close to) 80 columns. This method
the object, and the stripped information is lost. After performing a modifies the object, and the stripped information is lost. After
strip operation, the object is considered to have its entries in a performing a strip operation, the object is considered to have its
``random'' order, as it was just after object initialization and entries in a ``random'' order, as it was just after object
loading. If \code{strip_dirs()} causes two function names to be initialization and loading. If \method{strip_dirs()} causes two
indistinguishable (i.e., they are on the same line of the same function names to be indistinguishable (i.e., they are on the same
filename, and have the same function name), then the statistics for line of the same filename, and have the same function name), then the
these two entries are accumulated into a single entry. statistics for these two entries are accumulated into a single entry.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{add}{filename\optional{\, ...}} \begin{funcdesc}{add}{filename\optional{\, ...}}
This method of the \code{Stats} class accumulates additional profiling This method of the \class{Stats} class accumulates additional
information into the current profiling object. Its arguments should profiling information into the current profiling object. Its
refer to filenames created by the corresponding version of arguments should refer to filenames created by the corresponding
\code{profile.run()}. Statistics for identically named (re: file, version of \function{profile.run()}. Statistics for identically named
line, name) functions are automatically accumulated into single (re: file, line, name) functions are automatically accumulated into
function statistics. single function statistics.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{sort_stats}{key\optional{\, ...}} \begin{funcdesc}{sort_stats}{key\optional{\, ...}}
This method modifies the \code{Stats} object by sorting it according to the This method modifies the \class{Stats} object by sorting it according
supplied criteria. The argument is typically a string identifying the to the supplied criteria. The argument is typically a string
basis of a sort (example: \code{"time"} or \code{"name"}). identifying the basis of a sort (example: \code{"time"} or
\code{"name"}).
When more than one key is provided, then additional keys are used as When more than one key is provided, then additional keys are used as
secondary criteria when the there is equality in all keys selected secondary criteria when the there is equality in all keys selected
before them. For example, sort_stats('name', 'file') will sort all before them. For example, \samp{sort_stats('name', 'file')} will sort
the entries according to their function name, and resolve all ties all the entries according to their function name, and resolve all ties
(identical function names) by sorting by file name. (identical function names) by sorting by file name.
Abbreviations can be used for any key names, as long as the Abbreviations can be used for any key names, as long as the
@ -423,7 +434,7 @@ additional arguments will be silently ignored.
\begin{funcdesc}{reverse_order}{} \begin{funcdesc}{reverse_order}{}
This method for the \code{Stats} class reverses the ordering of the basic This method for the \class{Stats} class reverses the ordering of the basic
list within the object. This method is provided primarily for list within the object. This method is provided primarily for
compatibility with the old profiler. Its utility is questionable compatibility with the old profiler. Its utility is questionable
now that ascending vs descending order is properly selected based on now that ascending vs descending order is properly selected based on
@ -431,12 +442,12 @@ the sort key of choice.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{print_stats}{restriction\optional{\, ...}} \begin{funcdesc}{print_stats}{restriction\optional{\, ...}}
This method for the \code{Stats} class prints out a report as described This method for the \class{Stats} class prints out a report as described
in the \code{profile.run()} definition. in the \function{profile.run()} definition.
The order of the printing is based on the last \code{sort_stats()} The order of the printing is based on the last \method{sort_stats()}
operation done on the object (subject to caveats in \code{add()} and operation done on the object (subject to caveats in \method{add()} and
\code{strip_dirs())}. \method{strip_dirs()}.
The arguments provided (if any) can be used to limit the list down to The arguments provided (if any) can be used to limit the list down to
the significant entries. Initially, the list is taken to be the the significant entries. Initially, the list is taken to be the
@ -445,13 +456,13 @@ integer (to select a count of lines), or a decimal fraction between
0.0 and 1.0 inclusive (to select a percentage of lines), or a regular 0.0 and 1.0 inclusive (to select a percentage of lines), or a regular
expression (to pattern match the standard name that is printed; as of expression (to pattern match the standard name that is printed; as of
Python 1.5b1, this uses the Perl-style regular expression syntax Python 1.5b1, this uses the Perl-style regular expression syntax
defined by the \code{re} module). If several restrictions are defined by the \module{re} module). If several restrictions are
provided, then they are applied sequentially. For example: provided, then they are applied sequentially. For example:
\begin{verbatim} \begin{verbatim}
print_stats(.1, "foo:") print_stats(.1, "foo:")
\end{verbatim} \end{verbatim}
%
would first limit the printing to first 10\% of list, and then only would first limit the printing to first 10\% of list, and then only
print functions that were part of filename \samp{.*foo:}. In print functions that were part of filename \samp{.*foo:}. In
contrast, the command: contrast, the command:
@ -459,16 +470,16 @@ contrast, the command:
\begin{verbatim} \begin{verbatim}
print_stats("foo:", .1) print_stats("foo:", .1)
\end{verbatim} \end{verbatim}
%
would limit the list to all functions having file names \samp{.*foo:}, would limit the list to all functions having file names \samp{.*foo:},
and then proceed to only print the first 10\% of them. and then proceed to only print the first 10\% of them.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{print_callers}{restrictions\optional{\, ...}} \begin{funcdesc}{print_callers}{restrictions\optional{\, ...}}
This method for the \code{Stats} class prints a list of all functions This method for the \class{Stats} class prints a list of all functions
that called each function in the profiled database. The ordering is that called each function in the profiled database. The ordering is
identical to that provided by \code{print_stats()}, and the definition identical to that provided by \method{print_stats()}, and the definition
of the restricting argument is also identical. For convenience, a of the restricting argument is also identical. For convenience, a
number is shown in parentheses after each caller to show how many number is shown in parentheses after each caller to show how many
times this specific call was made. A second non-parenthesized number times this specific call was made. A second non-parenthesized number
@ -476,14 +487,14 @@ is the cumulative time spent in the function at the right.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{print_callees}{restrictions\optional{\, ...}} \begin{funcdesc}{print_callees}{restrictions\optional{\, ...}}
This method for the \code{Stats} class prints a list of all function This method for the \class{Stats} class prints a list of all function
that were called by the indicated function. Aside from this reversal that were called by the indicated function. Aside from this reversal
of direction of calls (re: called vs was called by), the arguments and of direction of calls (re: called vs was called by), the arguments and
ordering are identical to the \code{print_callers()} method. ordering are identical to the \method{print_callers()} method.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{ignore}{} \begin{funcdesc}{ignore}{}
This method of the \code{Stats} class is used to dispose of the value This method of the \class{Stats} class is used to dispose of the value
returned by earlier methods. All standard methods in this class returned by earlier methods. All standard methods in this class
return the instance that is being processed, so that the commands can return the instance that is being processed, so that the commands can
be strung together. For example: be strung together. For example:
@ -494,7 +505,7 @@ pstats.Stats('foofile').strip_dirs().sort_stats('cum') \
\end{verbatim} \end{verbatim}
% %
would perform all the indicated functions, but it would not return would perform all the indicated functions, but it would not return
the final reference to the \code{Stats} instance.% the final reference to the \class{Stats} instance.%
\footnote{ \footnote{
This was once necessary, when Python would print any unused expression This was once necessary, when Python would print any unused expression
result that was not \code{None}. The method is still defined for result that was not \code{None}. The method is still defined for
@ -507,10 +518,10 @@ backward compatibility.
There are two fundamental limitations on this profiler. The first is There are two fundamental limitations on this profiler. The first is
that it relies on the Python interpreter to dispatch \dfn{call}, that it relies on the Python interpreter to dispatch \dfn{call},
\dfn{return}, and \dfn{exception} events. Compiled C code does not \dfn{return}, and \dfn{exception} events. Compiled \C{} code does not
get interpreted, and hence is ``invisible'' to the profiler. All time get interpreted, and hence is ``invisible'' to the profiler. All time
spent in C code (including builtin functions) will be charged to the spent in \C{} code (including builtin functions) will be charged to the
Python function that invoked the C code. If the C code calls out Python function that invoked the \C{} code. If the \C{} code calls out
to some native Python code, then those calls will be profiled to some native Python code, then those calls will be profiled
properly. properly.
@ -559,21 +570,21 @@ pr.calibrate(100)
pr.calibrate(100) pr.calibrate(100)
pr.calibrate(100) pr.calibrate(100)
\end{verbatim} \end{verbatim}
%
The argument to calibrate() is the number of times to try to do the The argument to \method{calibrate()} is the number of times to try to
sample calls to get the CPU times. If your computer is \emph{very} do the sample calls to get the CPU times. If your computer is
fast, you might have to do: \emph{very} fast, you might have to do:
\begin{verbatim} \begin{verbatim}
pr.calibrate(1000) pr.calibrate(1000)
\end{verbatim} \end{verbatim}
%
or even: or even:
\begin{verbatim} \begin{verbatim}
pr.calibrate(10000) pr.calibrate(10000)
\end{verbatim} \end{verbatim}
%
The object of this exercise is to get a fairly consistent result. The object of this exercise is to get a fairly consistent result.
When you have a consistent answer, you are ready to use that number in When you have a consistent answer, you are ready to use that number in
the source code. For a Sun Sparcstation 1000 running Solaris 2.3, the the source code. For a Sun Sparcstation 1000 running Solaris 2.3, the
@ -598,14 +609,14 @@ def trace_dispatch(self, frame, event, arg):
self.t = r[0] + r[1] - t # put back unrecorded delta self.t = r[0] + r[1] - t # put back unrecorded delta
return return
\end{verbatim} \end{verbatim}
%
Note that if there is no calibration constant, then the line Note that if there is no calibration constant, then the line
containing the callibration constant should simply say: containing the callibration constant should simply say:
\begin{verbatim} \begin{verbatim}
t = t[0] + t[1] - self.t # no calibration constant t = t[0] + t[1] - self.t # no calibration constant
\end{verbatim} \end{verbatim}
%
You can also achieve the same results using a derived class (and the You can also achieve the same results using a derived class (and the
profiler will actually run equally fast!!), but the above method is profiler will actually run equally fast!!), but the above method is
the simplest to use. I could have made the profiler ``self the simplest to use. I could have made the profiler ``self
@ -620,7 +631,7 @@ at this point, when a constant can be used.
\section{Extensions --- Deriving Better Profilers} \section{Extensions --- Deriving Better Profilers}
\nodename{Profiler Extensions} \nodename{Profiler Extensions}
The \code{Profile} class of module \code{profile} was written so that The \class{Profile} class of module \module{profile} was written so that
derived classes could be developed to extend the profiler. Rather derived classes could be developed to extend the profiler. Rather
than describing all the details of such an effort, I'll just present than describing all the details of such an effort, I'll just present
the following two examples of derived classes that can be used to do the following two examples of derived classes that can be used to do
@ -636,10 +647,10 @@ function to call into the constructor:
\begin{verbatim} \begin{verbatim}
pr = profile.Profile(your_time_func) pr = profile.Profile(your_time_func)
\end{verbatim} \end{verbatim}
%
The resulting profiler will call \code{your_time_func()} instead of The resulting profiler will call \code{your_time_func()} instead of
\code{os.times()}. The function should return either a single number \function{os.times()}. The function should return either a single number
or a list of numbers (like what \code{os.times()} returns). If the or a list of numbers (like what \function{os.times()} returns). If the
function returns a single time number, or the list of returned numbers function returns a single time number, or the list of returned numbers
has length 2, then you will get an especially fast version of the has length 2, then you will get an especially fast version of the
dispatch routine. dispatch routine.
@ -647,12 +658,13 @@ dispatch routine.
Be warned that you \emph{should} calibrate the profiler class for the Be warned that you \emph{should} calibrate the profiler class for the
timer function that you choose. For most machines, a timer that timer function that you choose. For most machines, a timer that
returns a lone integer value will provide the best results in terms of returns a lone integer value will provide the best results in terms of
low overhead during profiling. (os.times is \emph{pretty} bad, 'cause low overhead during profiling. (\function{os.times()} is
it returns a tuple of floating point values, so all arithmetic is \emph{pretty} bad, 'cause it returns a tuple of floating point values,
floating point in the profiler!). If you want to substitute a so all arithmetic is floating point in the profiler!). If you want to
better timer in the cleanest fashion, you should derive a class, and substitute a better timer in the cleanest fashion, you should derive a
simply put in the replacement dispatch method that better handles your class, and simply put in the replacement dispatch method that better
timer call, along with the appropriate calibration constant :-). handles your timer call, along with the appropriate calibration
constant :-).
\subsection{OldProfile Class} \subsection{OldProfile Class}
@ -716,7 +728,7 @@ class OldProfile(Profile):
nc = nc + callers[func_caller] nc = nc + callers[func_caller]
self.stats[nor_func] = nc, nc, tt, ct, nor_callers self.stats[nor_func] = nc, nc, tt, ct, nor_callers
\end{verbatim} \end{verbatim}
%
\subsection{HotProfile Class} \subsection{HotProfile Class}
This profiler is the fastest derived profile example. It does not This profiler is the fastest derived profile example. It does not

174
Doc/libprofile.tex
View file

@ -39,7 +39,7 @@ As a result, it is probably clumsy code, but I don't know for sure yet
so that profiling would be a reasonable thing to do. I tried not to so that profiling would be a reasonable thing to do. I tried not to
repeat code fragments, but I'm sure I did some stuff in really awkward repeat code fragments, but I'm sure I did some stuff in really awkward
ways at times. Please send suggestions for improvements to: ways at times. Please send suggestions for improvements to:
\code{jar@netscape.com}. I won't promise \emph{any} support. ...but \email{jar@netscape.com}. I won't promise \emph{any} support. ...but
I'd appreciate the feedback. I'd appreciate the feedback.
@ -49,10 +49,12 @@ I'd appreciate the feedback.
A \dfn{profiler} is a program that describes the run time performance A \dfn{profiler} is a program that describes the run time performance
of a program, providing a variety of statistics. This documentation of a program, providing a variety of statistics. This documentation
describes the profiler functionality provided in the modules describes the profiler functionality provided in the modules
\code{profile} and \code{pstats.} This profiler provides \module{profile} and \module{pstats}. This profiler provides
\dfn{deterministic profiling} of any Python programs. It also \dfn{deterministic profiling} of any Python programs. It also
provides a series of report generation tools to allow users to rapidly provides a series of report generation tools to allow users to rapidly
examine the results of a profile operation. examine the results of a profile operation.
\index{deterministic profiling}
\index{profiling, deterministic}
\section{How Is This Profiler Different From The Old Profiler?} \section{How Is This Profiler Different From The Old Profiler?}
@ -81,7 +83,7 @@ profiler \emph{during} profiling (and charged to user's code!).
\item[Speed increased:] \item[Speed increased:]
Overhead CPU cost was reduced by more than a factor of two (perhaps a Overhead CPU cost was reduced by more than a factor of two (perhaps a
factor of five), lightweight profiler module is all that must be factor of five), lightweight profiler module is all that must be
loaded, and the report generating module (\code{pstats}) is not needed loaded, and the report generating module (\module{pstats}) is not needed
during profiling. during profiling.
\item[Recursive functions support:] \item[Recursive functions support:]
@ -116,7 +118,7 @@ The above action would cause \samp{foo()} to be run, and a series of
informative lines (the profile) to be printed. The above approach is informative lines (the profile) to be printed. The above approach is
most useful when working with the interpreter. If you would like to most useful when working with the interpreter. If you would like to
save the results of a profile into a file for later examination, you save the results of a profile into a file for later examination, you
can supply a file name as the second argument to the \code{run()} can supply a file name as the second argument to the \function{run()}
function: function:
\begin{verbatim} \begin{verbatim}
@ -124,12 +126,15 @@ import profile
profile.run("foo()", 'fooprof') profile.run("foo()", 'fooprof')
\end{verbatim} \end{verbatim}
% %
\code{profile.py} can also be invoked as The file \file{profile.py} can also be invoked as
a script to profile another script. For example: a script to profile another script. For example:
\code{python} \code{/usr/local/lib/python1.4/profile.py myscript.py}
\begin{verbatim}
python /usr/local/lib/python1.4/profile.py myscript.py
\end{verbatim}
When you wish to review the profile, you should use the methods in the When you wish to review the profile, you should use the methods in the
\code{pstats} module. Typically you would load the statistics data as \module{pstats} module. Typically you would load the statistics data as
follows: follows:
\begin{verbatim} \begin{verbatim}
@ -137,10 +142,10 @@ import pstats
p = pstats.Stats('fooprof') p = pstats.Stats('fooprof')
\end{verbatim} \end{verbatim}
% %
The class \code{Stats} (the above code just created an instance of The class \class{Stats} (the above code just created an instance of
this class) has a variety of methods for manipulating and printing the this class) has a variety of methods for manipulating and printing the
data that was just read into \samp{p}. When you ran data that was just read into \samp{p}. When you ran
\code{profile.run()} above, what was printed was the result of three \function{profile.run()} above, what was printed was the result of three
method calls: method calls:
\begin{verbatim} \begin{verbatim}
@ -188,7 +193,7 @@ p.sort_stats('file').print_stats('__init__')
% %
This will sort all the statistics by file name, and then print out This will sort all the statistics by file name, and then print out
statistics for only the class init methods ('cause they are spelled statistics for only the class init methods ('cause they are spelled
with \code{__init__} in them). As one final example, you could try: with \samp{__init__} in them). As one final example, you could try:
\begin{verbatim} \begin{verbatim}
p.sort_stats('time', 'cum').print_stats(.5, 'init') p.sort_stats('time', 'cum').print_stats(.5, 'init')
@ -206,7 +211,7 @@ now (\samp{p} is still sorted according to the last criteria) do:
\begin{verbatim} \begin{verbatim}
p.print_callers(.5, 'init') p.print_callers(.5, 'init')
\end{verbatim} \end{verbatim}
%
and you would get a list of callers for each of the listed functions. and you would get a list of callers for each of the listed functions.
If you want more functionality, you're going to have to read the If you want more functionality, you're going to have to read the
@ -252,12 +257,12 @@ of algorithms to be directly compared to iterative implementations.
\section{Reference Manual} \section{Reference Manual}
\setindexsubitem{(profiler function)} \setindexsubitem{(in module profile)}
The primary entry point for the profiler is the global function The primary entry point for the profiler is the global function
\code{profile.run()}. It is typically used to create any profile \function{profile.run()}. It is typically used to create any profile
information. The reports are formatted and printed using methods of information. The reports are formatted and printed using methods of
the class \code{pstats.Stats}. The following is a description of all the class \class{pstats.Stats}. The following is a description of all
of these standard entry points and functions. For a more in-depth of these standard entry points and functions. For a more in-depth
view of some of the code, consider reading the later section on view of some of the code, consider reading the later section on
Profiler Extensions, which includes discussion of how to derive Profiler Extensions, which includes discussion of how to derive
@ -267,8 +272,8 @@ code for these modules.
\begin{funcdesc}{profile.run}{string\optional{\, filename\optional{\, ...}}} \begin{funcdesc}{profile.run}{string\optional{\, filename\optional{\, ...}}}
This function takes a single argument that has can be passed to the This function takes a single argument that has can be passed to the
\code{exec} statement, and an optional file name. In all cases this \keyword{exec} statement, and an optional file name. In all cases this
routine attempts to \code{exec} its first argument, and gather profiling routine attempts to \keyword{exec} its first argument, and gather profiling
statistics from the execution. If no file name is present, then this statistics from the execution. If no file name is present, then this
function automatically prints a simple profiling report, sorted by the function automatically prints a simple profiling report, sorted by the
standard name string (file/line/function-name) that is presented in standard name string (file/line/function-name) that is presented in
@ -328,23 +333,28 @@ printed.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{pstats.Stats}{filename\optional{\, ...}} Analysis of the profiler data is done using this class from the
\module{pstats} module:
\setindexsubitem{(in module pstats)}
\begin{classdesc}{Stats}{filename\optional{\, ...}}
This class constructor creates an instance of a ``statistics object'' This class constructor creates an instance of a ``statistics object''
from a \var{filename} (or set of filenames). \code{Stats} objects are from a \var{filename} (or set of filenames). \class{Stats} objects are
manipulated by methods, in order to print useful reports. manipulated by methods, in order to print useful reports.
The file selected by the above constructor must have been created by The file selected by the above constructor must have been created by
the corresponding version of \code{profile}. To be specific, there is the corresponding version of \module{profile}. To be specific, there is
\emph{NO} file compatibility guaranteed with future versions of this \emph{no} file compatibility guaranteed with future versions of this
profiler, and there is no compatibility with files produced by other profiler, and there is no compatibility with files produced by other
profilers (e.g., the old system profiler). profilers (e.g., the old system profiler).
If several files are provided, all the statistics for identical If several files are provided, all the statistics for identical
functions will be coalesced, so that an overall view of several functions will be coalesced, so that an overall view of several
processes can be considered in a single report. If additional files processes can be considered in a single report. If additional files
need to be combined with data in an existing \code{Stats} object, the need to be combined with data in an existing \class{Stats} object, the
\code{add()} method can be used. \method{add()} method can be used.
\end{funcdesc} \end{classdesc}
\subsection{The \sectcode{Stats} Class} \subsection{The \sectcode{Stats} Class}
@ -352,37 +362,38 @@ need to be combined with data in an existing \code{Stats} object, the
\setindexsubitem{(Stats method)} \setindexsubitem{(Stats method)}
\begin{funcdesc}{strip_dirs}{} \begin{funcdesc}{strip_dirs}{}
This method for the \code{Stats} class removes all leading path information This method for the \class{Stats} class removes all leading path
from file names. It is very useful in reducing the size of the information from file names. It is very useful in reducing the size
printout to fit within (close to) 80 columns. This method modifies of the printout to fit within (close to) 80 columns. This method
the object, and the stripped information is lost. After performing a modifies the object, and the stripped information is lost. After
strip operation, the object is considered to have its entries in a performing a strip operation, the object is considered to have its
``random'' order, as it was just after object initialization and entries in a ``random'' order, as it was just after object
loading. If \code{strip_dirs()} causes two function names to be initialization and loading. If \method{strip_dirs()} causes two
indistinguishable (i.e., they are on the same line of the same function names to be indistinguishable (i.e., they are on the same
filename, and have the same function name), then the statistics for line of the same filename, and have the same function name), then the
these two entries are accumulated into a single entry. statistics for these two entries are accumulated into a single entry.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{add}{filename\optional{\, ...}} \begin{funcdesc}{add}{filename\optional{\, ...}}
This method of the \code{Stats} class accumulates additional profiling This method of the \class{Stats} class accumulates additional
information into the current profiling object. Its arguments should profiling information into the current profiling object. Its
refer to filenames created by the corresponding version of arguments should refer to filenames created by the corresponding
\code{profile.run()}. Statistics for identically named (re: file, version of \function{profile.run()}. Statistics for identically named
line, name) functions are automatically accumulated into single (re: file, line, name) functions are automatically accumulated into
function statistics. single function statistics.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{sort_stats}{key\optional{\, ...}} \begin{funcdesc}{sort_stats}{key\optional{\, ...}}
This method modifies the \code{Stats} object by sorting it according to the This method modifies the \class{Stats} object by sorting it according
supplied criteria. The argument is typically a string identifying the to the supplied criteria. The argument is typically a string
basis of a sort (example: \code{"time"} or \code{"name"}). identifying the basis of a sort (example: \code{"time"} or
\code{"name"}).
When more than one key is provided, then additional keys are used as When more than one key is provided, then additional keys are used as
secondary criteria when the there is equality in all keys selected secondary criteria when the there is equality in all keys selected
before them. For example, sort_stats('name', 'file') will sort all before them. For example, \samp{sort_stats('name', 'file')} will sort
the entries according to their function name, and resolve all ties all the entries according to their function name, and resolve all ties
(identical function names) by sorting by file name. (identical function names) by sorting by file name.
Abbreviations can be used for any key names, as long as the Abbreviations can be used for any key names, as long as the
@ -423,7 +434,7 @@ additional arguments will be silently ignored.
\begin{funcdesc}{reverse_order}{} \begin{funcdesc}{reverse_order}{}
This method for the \code{Stats} class reverses the ordering of the basic This method for the \class{Stats} class reverses the ordering of the basic
list within the object. This method is provided primarily for list within the object. This method is provided primarily for
compatibility with the old profiler. Its utility is questionable compatibility with the old profiler. Its utility is questionable
now that ascending vs descending order is properly selected based on now that ascending vs descending order is properly selected based on
@ -431,12 +442,12 @@ the sort key of choice.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{print_stats}{restriction\optional{\, ...}} \begin{funcdesc}{print_stats}{restriction\optional{\, ...}}
This method for the \code{Stats} class prints out a report as described This method for the \class{Stats} class prints out a report as described
in the \code{profile.run()} definition. in the \function{profile.run()} definition.
The order of the printing is based on the last \code{sort_stats()} The order of the printing is based on the last \method{sort_stats()}
operation done on the object (subject to caveats in \code{add()} and operation done on the object (subject to caveats in \method{add()} and
\code{strip_dirs())}. \method{strip_dirs()}.
The arguments provided (if any) can be used to limit the list down to The arguments provided (if any) can be used to limit the list down to
the significant entries. Initially, the list is taken to be the the significant entries. Initially, the list is taken to be the
@ -445,13 +456,13 @@ integer (to select a count of lines), or a decimal fraction between
0.0 and 1.0 inclusive (to select a percentage of lines), or a regular 0.0 and 1.0 inclusive (to select a percentage of lines), or a regular
expression (to pattern match the standard name that is printed; as of expression (to pattern match the standard name that is printed; as of
Python 1.5b1, this uses the Perl-style regular expression syntax Python 1.5b1, this uses the Perl-style regular expression syntax
defined by the \code{re} module). If several restrictions are defined by the \module{re} module). If several restrictions are
provided, then they are applied sequentially. For example: provided, then they are applied sequentially. For example:
\begin{verbatim} \begin{verbatim}
print_stats(.1, "foo:") print_stats(.1, "foo:")
\end{verbatim} \end{verbatim}
%
would first limit the printing to first 10\% of list, and then only would first limit the printing to first 10\% of list, and then only
print functions that were part of filename \samp{.*foo:}. In print functions that were part of filename \samp{.*foo:}. In
contrast, the command: contrast, the command:
@ -459,16 +470,16 @@ contrast, the command:
\begin{verbatim} \begin{verbatim}
print_stats("foo:", .1) print_stats("foo:", .1)
\end{verbatim} \end{verbatim}
%
would limit the list to all functions having file names \samp{.*foo:}, would limit the list to all functions having file names \samp{.*foo:},
and then proceed to only print the first 10\% of them. and then proceed to only print the first 10\% of them.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{print_callers}{restrictions\optional{\, ...}} \begin{funcdesc}{print_callers}{restrictions\optional{\, ...}}
This method for the \code{Stats} class prints a list of all functions This method for the \class{Stats} class prints a list of all functions
that called each function in the profiled database. The ordering is that called each function in the profiled database. The ordering is
identical to that provided by \code{print_stats()}, and the definition identical to that provided by \method{print_stats()}, and the definition
of the restricting argument is also identical. For convenience, a of the restricting argument is also identical. For convenience, a
number is shown in parentheses after each caller to show how many number is shown in parentheses after each caller to show how many
times this specific call was made. A second non-parenthesized number times this specific call was made. A second non-parenthesized number
@ -476,14 +487,14 @@ is the cumulative time spent in the function at the right.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{print_callees}{restrictions\optional{\, ...}} \begin{funcdesc}{print_callees}{restrictions\optional{\, ...}}
This method for the \code{Stats} class prints a list of all function This method for the \class{Stats} class prints a list of all function
that were called by the indicated function. Aside from this reversal that were called by the indicated function. Aside from this reversal
of direction of calls (re: called vs was called by), the arguments and of direction of calls (re: called vs was called by), the arguments and
ordering are identical to the \code{print_callers()} method. ordering are identical to the \method{print_callers()} method.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{ignore}{} \begin{funcdesc}{ignore}{}
This method of the \code{Stats} class is used to dispose of the value This method of the \class{Stats} class is used to dispose of the value
returned by earlier methods. All standard methods in this class returned by earlier methods. All standard methods in this class
return the instance that is being processed, so that the commands can return the instance that is being processed, so that the commands can
be strung together. For example: be strung together. For example:
@ -494,7 +505,7 @@ pstats.Stats('foofile').strip_dirs().sort_stats('cum') \
\end{verbatim} \end{verbatim}
% %
would perform all the indicated functions, but it would not return would perform all the indicated functions, but it would not return
the final reference to the \code{Stats} instance.% the final reference to the \class{Stats} instance.%
\footnote{ \footnote{
This was once necessary, when Python would print any unused expression This was once necessary, when Python would print any unused expression
result that was not \code{None}. The method is still defined for result that was not \code{None}. The method is still defined for
@ -507,10 +518,10 @@ backward compatibility.
There are two fundamental limitations on this profiler. The first is There are two fundamental limitations on this profiler. The first is
that it relies on the Python interpreter to dispatch \dfn{call}, that it relies on the Python interpreter to dispatch \dfn{call},
\dfn{return}, and \dfn{exception} events. Compiled C code does not \dfn{return}, and \dfn{exception} events. Compiled \C{} code does not
get interpreted, and hence is ``invisible'' to the profiler. All time get interpreted, and hence is ``invisible'' to the profiler. All time
spent in C code (including builtin functions) will be charged to the spent in \C{} code (including builtin functions) will be charged to the
Python function that invoked the C code. If the C code calls out Python function that invoked the \C{} code. If the \C{} code calls out
to some native Python code, then those calls will be profiled to some native Python code, then those calls will be profiled
properly. properly.
@ -559,21 +570,21 @@ pr.calibrate(100)
pr.calibrate(100) pr.calibrate(100)
pr.calibrate(100) pr.calibrate(100)
\end{verbatim} \end{verbatim}
%
The argument to calibrate() is the number of times to try to do the The argument to \method{calibrate()} is the number of times to try to
sample calls to get the CPU times. If your computer is \emph{very} do the sample calls to get the CPU times. If your computer is
fast, you might have to do: \emph{very} fast, you might have to do:
\begin{verbatim} \begin{verbatim}
pr.calibrate(1000) pr.calibrate(1000)
\end{verbatim} \end{verbatim}
%
or even: or even:
\begin{verbatim} \begin{verbatim}
pr.calibrate(10000) pr.calibrate(10000)
\end{verbatim} \end{verbatim}
%
The object of this exercise is to get a fairly consistent result. The object of this exercise is to get a fairly consistent result.
When you have a consistent answer, you are ready to use that number in When you have a consistent answer, you are ready to use that number in
the source code. For a Sun Sparcstation 1000 running Solaris 2.3, the the source code. For a Sun Sparcstation 1000 running Solaris 2.3, the
@ -598,14 +609,14 @@ def trace_dispatch(self, frame, event, arg):
self.t = r[0] + r[1] - t # put back unrecorded delta self.t = r[0] + r[1] - t # put back unrecorded delta
return return
\end{verbatim} \end{verbatim}
%
Note that if there is no calibration constant, then the line Note that if there is no calibration constant, then the line
containing the callibration constant should simply say: containing the callibration constant should simply say:
\begin{verbatim} \begin{verbatim}
t = t[0] + t[1] - self.t # no calibration constant t = t[0] + t[1] - self.t # no calibration constant
\end{verbatim} \end{verbatim}
%
You can also achieve the same results using a derived class (and the You can also achieve the same results using a derived class (and the
profiler will actually run equally fast!!), but the above method is profiler will actually run equally fast!!), but the above method is
the simplest to use. I could have made the profiler ``self the simplest to use. I could have made the profiler ``self
@ -620,7 +631,7 @@ at this point, when a constant can be used.
\section{Extensions --- Deriving Better Profilers} \section{Extensions --- Deriving Better Profilers}
\nodename{Profiler Extensions} \nodename{Profiler Extensions}
The \code{Profile} class of module \code{profile} was written so that The \class{Profile} class of module \module{profile} was written so that
derived classes could be developed to extend the profiler. Rather derived classes could be developed to extend the profiler. Rather
than describing all the details of such an effort, I'll just present than describing all the details of such an effort, I'll just present
the following two examples of derived classes that can be used to do the following two examples of derived classes that can be used to do
@ -636,10 +647,10 @@ function to call into the constructor:
\begin{verbatim} \begin{verbatim}
pr = profile.Profile(your_time_func) pr = profile.Profile(your_time_func)
\end{verbatim} \end{verbatim}
%
The resulting profiler will call \code{your_time_func()} instead of The resulting profiler will call \code{your_time_func()} instead of
\code{os.times()}. The function should return either a single number \function{os.times()}. The function should return either a single number
or a list of numbers (like what \code{os.times()} returns). If the or a list of numbers (like what \function{os.times()} returns). If the
function returns a single time number, or the list of returned numbers function returns a single time number, or the list of returned numbers
has length 2, then you will get an especially fast version of the has length 2, then you will get an especially fast version of the
dispatch routine. dispatch routine.
@ -647,12 +658,13 @@ dispatch routine.
Be warned that you \emph{should} calibrate the profiler class for the Be warned that you \emph{should} calibrate the profiler class for the
timer function that you choose. For most machines, a timer that timer function that you choose. For most machines, a timer that
returns a lone integer value will provide the best results in terms of returns a lone integer value will provide the best results in terms of
low overhead during profiling. (os.times is \emph{pretty} bad, 'cause low overhead during profiling. (\function{os.times()} is
it returns a tuple of floating point values, so all arithmetic is \emph{pretty} bad, 'cause it returns a tuple of floating point values,
floating point in the profiler!). If you want to substitute a so all arithmetic is floating point in the profiler!). If you want to
better timer in the cleanest fashion, you should derive a class, and substitute a better timer in the cleanest fashion, you should derive a
simply put in the replacement dispatch method that better handles your class, and simply put in the replacement dispatch method that better
timer call, along with the appropriate calibration constant :-). handles your timer call, along with the appropriate calibration
constant :-).
\subsection{OldProfile Class} \subsection{OldProfile Class}
@ -716,7 +728,7 @@ class OldProfile(Profile):
nc = nc + callers[func_caller] nc = nc + callers[func_caller]
self.stats[nor_func] = nc, nc, tt, ct, nor_callers self.stats[nor_func] = nc, nc, tt, ct, nor_callers
\end{verbatim} \end{verbatim}
%
\subsection{HotProfile Class} \subsection{HotProfile Class}
This profiler is the fastest derived profile example. It does not This profiler is the fastest derived profile example. It does not