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bpo-31415: Add _PyTime_GetPerfCounter() and use it for -X importtime (#3936)

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* Add _PyTime_GetPerfCounter()
* Use _PyTime_GetPerfCounter() for -X importtime
This commit is contained in:
Victor Stinner 2017-10-10 02:51:50 -07:00 • committed by GitHub
parent 14aa00b519
commit a997c7b434
4 changed files with 112 additions and 60 deletions
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4
Python/import.c
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@ -1695,7 +1695,7 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals,
if (ximporttime) {
import_level++;
t1 = _PyTime_GetMonotonicClock();
t1 = _PyTime_GetPerfCounter();
accumulated = 0;
}
@ -1711,7 +1711,7 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals,
mod != NULL);
if (ximporttime) {
_PyTime_t cum = _PyTime_GetMonotonicClock() - t1;
_PyTime_t cum = _PyTime_GetPerfCounter() - t1;
import_level--;
fprintf(stderr, "import time: %9ld | %10ld | %*s%s\n",

81
Python/pytime.c
View file

@ -285,8 +285,8 @@ _PyTime_FromTimeval(_PyTime_t *tp, struct timeval *tv, int raise)
#endif
static int
_PyTime_FromFloatObject(_PyTime_t *t, double value, _PyTime_round_t round,
long unit_to_ns)
_PyTime_FromDouble(_PyTime_t *t, double value, _PyTime_round_t round,
long unit_to_ns)
{
/* volatile avoids optimization changing how numbers are rounded */
volatile double d;
@ -315,7 +315,7 @@ _PyTime_FromObject(_PyTime_t *t, PyObject *obj, _PyTime_round_t round,
PyErr_SetString(PyExc_ValueError, "Invalid value NaN (not a number)");
return -1;
}
return _PyTime_FromFloatObject(t, d, round, unit_to_ns);
return _PyTime_FromDouble(t, d, round, unit_to_ns);
}
else {
long long sec;
@ -779,19 +779,80 @@ _PyTime_GetMonotonicClockWithInfo(_PyTime_t *tp, _Py_clock_info_t *info)
return pymonotonic(tp, info, 1);
}
#ifdef MS_WINDOWS
int
_PyTime_GetWinPerfCounterWithInfo(_PyTime_t *t, _Py_clock_info_t *info)
{
static LONGLONG cpu_frequency = 0;
static LONGLONG ctrStart;
LARGE_INTEGER now;
double diff;
if (cpu_frequency == 0) {
LARGE_INTEGER freq;
QueryPerformanceCounter(&now);
ctrStart = now.QuadPart;
if (!QueryPerformanceFrequency(&freq) || freq.QuadPart == 0) {
PyErr_SetFromWindowsErr(0);
return -1;
}
cpu_frequency = freq.QuadPart;
}
QueryPerformanceCounter(&now);
diff = (double)(now.QuadPart - ctrStart);
if (info) {
info->implementation = "QueryPerformanceCounter()";
info->resolution = 1.0 / (double)cpu_frequency;
info->monotonic = 1;
info->adjustable = 0;
}
diff = diff / (double)cpu_frequency;
return _PyTime_FromDouble(t, diff, _PyTime_ROUND_FLOOR, SEC_TO_NS);
}
#endif
int
_PyTime_GetPerfCounterWithInfo(_PyTime_t *t, _Py_clock_info_t *info)
{
#ifdef MS_WINDOWS
return _PyTime_GetWinPerfCounterWithInfo(t, info);
#else
return _PyTime_GetMonotonicClockWithInfo(t, info);
#endif
}
_PyTime_t
_PyTime_GetPerfCounter(void)
{
_PyTime_t t;
if (_PyTime_GetPerfCounterWithInfo(&t, NULL) < 0) {
/* should not happen, _PyTime_Init() checked the clock at startup */
Py_UNREACHABLE();
}
return t;
}
int
_PyTime_Init(void)
{
/* check that the 3 most important clocks are working properly
to not have to check for exceptions at runtime. If a clock works once,
it cannot fail in next calls. */
_PyTime_t t;
/* ensure that the system clock works */
if (_PyTime_GetSystemClockWithInfo(&t, NULL) < 0)
if (_PyTime_GetSystemClockWithInfo(&t, NULL) < 0) {
return -1;
/* ensure that the operating system provides a monotonic clock */
if (_PyTime_GetMonotonicClockWithInfo(&t, NULL) < 0)
}
if (_PyTime_GetMonotonicClockWithInfo(&t, NULL) < 0) {
return -1;
}
if (_PyTime_GetPerfCounterWithInfo(&t, NULL) < 0) {
return -1;
}
return 0;
}