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GH-118093: Improve handling of short and mid-loop traces (GH-122252)

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Brandt Bucher 2024-07-29 14:49:17 -07:00 • committed by GitHub
parent 78df1043db
commit 7797182b78
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GPG key ID: B5690EEEBB952194
2 changed files with 34 additions and 35 deletions
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5
Objects/genobject.c
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@ -342,8 +342,9 @@ _PyGen_yf(PyGenObject *gen)
{
if (gen->gi_frame_state == FRAME_SUSPENDED_YIELD_FROM) {
_PyInterpreterFrame *frame = &gen->gi_iframe;
assert(is_resume(frame->instr_ptr));
assert((frame->instr_ptr->op.arg & RESUME_OPARG_LOCATION_MASK) >= RESUME_AFTER_YIELD_FROM);
// GH-122390: These asserts are wrong in the presence of ENTER_EXECUTOR!
// assert(is_resume(frame->instr_ptr));
// assert((frame->instr_ptr->op.arg & RESUME_OPARG_LOCATION_MASK) >= RESUME_AFTER_YIELD_FROM);
return PyStackRef_AsPyObjectNew(_PyFrame_StackPeek(frame));
}
return NULL;

56
Python/optimizer.c
View file

@ -503,8 +503,7 @@ add_to_trace(
if (trace_stack_depth >= TRACE_STACK_SIZE) { \
DPRINTF(2, "Trace stack overflow\n"); \
OPT_STAT_INC(trace_stack_overflow); \
trace_length = 0; \
goto done; \
return 0; \
} \
assert(func == NULL || func->func_code == (PyObject *)code); \
trace_stack[trace_stack_depth].func = func; \
@ -550,6 +549,7 @@ translate_bytecode_to_trace(
} trace_stack[TRACE_STACK_SIZE];
int trace_stack_depth = 0;
int confidence = CONFIDENCE_RANGE; // Adjusted by branch instructions
bool jump_seen = false;
#ifdef Py_DEBUG
char *python_lltrace = Py_GETENV("PYTHON_LLTRACE");
@ -568,7 +568,6 @@ translate_bytecode_to_trace(
ADD_TO_TRACE(_START_EXECUTOR, 0, (uintptr_t)instr, INSTR_IP(instr, code));
uint32_t target = 0;
top: // Jump here after _PUSH_FRAME or likely branches
for (;;) {
target = INSTR_IP(instr, code);
// Need space for _DEOPT
@ -577,6 +576,13 @@ translate_bytecode_to_trace(
uint32_t opcode = instr->op.code;
uint32_t oparg = instr->op.arg;
if (!progress_needed && instr == initial_instr) {
// We have looped around to the start:
RESERVE(1);
ADD_TO_TRACE(_JUMP_TO_TOP, 0, 0, 0);
goto done;
}
DPRINTF(2, "%d: %s(%d)\n", target, _PyOpcode_OpName[opcode], oparg);
if (opcode == ENTER_EXECUTOR) {
@ -603,30 +609,21 @@ translate_bytecode_to_trace(
/* Special case the first instruction,
* so that we can guarantee forward progress */
if (progress_needed) {
progress_needed = false;
if (opcode == JUMP_BACKWARD || opcode == JUMP_BACKWARD_NO_INTERRUPT) {
instr += 1 + _PyOpcode_Caches[opcode] - (int32_t)oparg;
initial_instr = instr;
if (opcode == JUMP_BACKWARD) {
ADD_TO_TRACE(_TIER2_RESUME_CHECK, 0, 0, target);
}
continue;
}
else {
if (OPCODE_HAS_EXIT(opcode) || OPCODE_HAS_DEOPT(opcode)) {
opcode = _PyOpcode_Deopt[opcode];
}
assert(!OPCODE_HAS_EXIT(opcode));
assert(!OPCODE_HAS_DEOPT(opcode));
}
}
if (OPCODE_HAS_EXIT(opcode)) {
// Make space for exit code
// Make space for side exit and final _EXIT_TRACE:
RESERVE_RAW(2, "_EXIT_TRACE");
max_length--;
}
if (OPCODE_HAS_ERROR(opcode)) {
// Make space for error code
// Make space for error stub and final _EXIT_TRACE:
RESERVE_RAW(2, "_ERROR_POP_N");
max_length--;
}
switch (opcode) {
@ -672,20 +669,19 @@ translate_bytecode_to_trace(
}
case JUMP_BACKWARD:
ADD_TO_TRACE(_CHECK_PERIODIC, 0, 0, target);
_Py_FALLTHROUGH;
case JUMP_BACKWARD_NO_INTERRUPT:
{
_Py_CODEUNIT *target = instr + 1 + _PyOpcode_Caches[opcode] - (int)oparg;
if (target == initial_instr) {
/* We have looped round to the start */
RESERVE(1);
ADD_TO_TRACE(_JUMP_TO_TOP, 0, 0, 0);
}
else {
instr += 1 + _PyOpcode_Caches[_PyOpcode_Deopt[opcode]] - (int)oparg;
if (jump_seen) {
OPT_STAT_INC(inner_loop);
DPRINTF(2, "JUMP_BACKWARD not to top ends trace\n");
}
goto done;
}
jump_seen = true;
goto top;
}
case JUMP_FORWARD:
{
@ -904,6 +900,9 @@ translate_bytecode_to_trace(
assert(instr->op.code == POP_TOP);
instr++;
}
top:
// Jump here after _PUSH_FRAME or likely branches.
progress_needed = false;
} // End for (;;)
done:
@ -911,16 +910,15 @@ translate_bytecode_to_trace(
TRACE_STACK_POP();
}
assert(code == initial_code);
// Skip short traces like _SET_IP, LOAD_FAST, _SET_IP, _EXIT_TRACE
if (progress_needed || trace_length < 5) {
// Skip short traces where we can't even translate a single instruction:
if (progress_needed) {
OPT_STAT_INC(trace_too_short);
DPRINTF(2,
"No trace for %s (%s:%d) at byte offset %d (%s)\n",
"No trace for %s (%s:%d) at byte offset %d (no progress)\n",
PyUnicode_AsUTF8(code->co_qualname),
PyUnicode_AsUTF8(code->co_filename),
code->co_firstlineno,
2 * INSTR_IP(initial_instr, code),
progress_needed ? "no progress" : "too short");
2 * INSTR_IP(initial_instr, code));
return 0;
}
if (trace[trace_length-1].opcode != _JUMP_TO_TOP) {