gh-112175: Add eval_breaker to PyThreadState (#115194)

This change adds an `eval_breaker` field to `PyThreadState`. The primary
motivation is for performance in free-threaded builds: with thread-local eval
breakers, we can stop a specific thread (e.g., for an async exception) without
interrupting other threads.

The source of truth for the global instrumentation version is stored in the
`instrumentation_version` field in PyInterpreterState. Threads usually read the
version from their local `eval_breaker`, where it continues to be colocated
with the eval breaker bits.
This commit is contained in:
Brett Simmers 2024-02-20 06:57:48 -08:00 committed by GitHub
parent e71468ba4f
commit 0749244d13
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GPG key ID: B5690EEEBB952194
19 changed files with 265 additions and 172 deletions

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@ -8,7 +8,6 @@
#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
#include "pycore_ceval.h" // _PyEval_SignalAsyncExc()
#include "pycore_code.h"
#include "pycore_emscripten_signal.h" // _Py_CHECK_EMSCRIPTEN_SIGNALS
#include "pycore_function.h"
@ -146,7 +145,7 @@ dummy_func(
TIER_ONE_ONLY
assert(frame == tstate->current_frame);
uintptr_t global_version =
_Py_atomic_load_uintptr_relaxed(&tstate->interp->ceval.eval_breaker) &
_Py_atomic_load_uintptr_relaxed(&tstate->eval_breaker) &
~_PY_EVAL_EVENTS_MASK;
uintptr_t code_version = _PyFrame_GetCode(frame)->_co_instrumentation_version;
assert((code_version & 255) == 0);
@ -168,14 +167,14 @@ dummy_func(
DEOPT_IF(_Py_emscripten_signal_clock == 0);
_Py_emscripten_signal_clock -= Py_EMSCRIPTEN_SIGNAL_HANDLING;
#endif
uintptr_t eval_breaker = _Py_atomic_load_uintptr_relaxed(&tstate->interp->ceval.eval_breaker);
uintptr_t eval_breaker = _Py_atomic_load_uintptr_relaxed(&tstate->eval_breaker);
uintptr_t version = _PyFrame_GetCode(frame)->_co_instrumentation_version;
assert((version & _PY_EVAL_EVENTS_MASK) == 0);
DEOPT_IF(eval_breaker != version);
}
inst(INSTRUMENTED_RESUME, (--)) {
uintptr_t global_version = _Py_atomic_load_uintptr_relaxed(&tstate->interp->ceval.eval_breaker) & ~_PY_EVAL_EVENTS_MASK;
uintptr_t global_version = _Py_atomic_load_uintptr_relaxed(&tstate->eval_breaker) & ~_PY_EVAL_EVENTS_MASK;
uintptr_t code_version = _PyFrame_GetCode(frame)->_co_instrumentation_version;
if (code_version != global_version) {
if (_Py_Instrument(_PyFrame_GetCode(frame), tstate->interp)) {