diff options
| author | Mark Shannon <mark@hotpy.org> | 2024-02-13 14:16:37 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-02-13 14:16:37 (GMT) |
| commit | f9f6156c5affc039d4ee6b6f4999daf0d5896428 (patch) | |
| tree | 063a0d3da50ec32d1bdd265d0b305f9365ced7da /Python/bytecodes.c | |
| parent | 7cce8576226249461baa91c4a89770a1823b44a4 (diff) | |
| download | cpython-f9f6156c5affc039d4ee6b6f4999daf0d5896428.zip cpython-f9f6156c5affc039d4ee6b6f4999daf0d5896428.tar.gz cpython-f9f6156c5affc039d4ee6b6f4999daf0d5896428.tar.bz2 | |
GH-113710: Backedge counter improvements. (GH-115166)
Diffstat (limited to 'Python/bytecodes.c')
| -rw-r--r-- | Python/bytecodes.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/Python/bytecodes.c b/Python/bytecodes.c index f7c7e36..2ad5878 100644 --- a/Python/bytecodes.c +++ b/Python/bytecodes.c @@ -2318,13 +2318,16 @@ dummy_func( assert(oparg <= INSTR_OFFSET()); JUMPBY(-oparg); #if ENABLE_SPECIALIZATION - this_instr[1].cache += (1 << OPTIMIZER_BITS_IN_COUNTER); + uint16_t counter = this_instr[1].cache; + this_instr[1].cache = counter + (1 << OPTIMIZER_BITS_IN_COUNTER); /* We are using unsigned values, but we really want signed values, so - * do the 2s complement comparison manually */ - uint16_t ucounter = this_instr[1].cache + (1 << 15); - uint16_t threshold = tstate->interp->optimizer_backedge_threshold + (1 << 15); + * do the 2s complement adjustment manually */ + uint32_t offset_counter = counter ^ (1 << 15); + uint32_t threshold = tstate->interp->optimizer_backedge_threshold; + assert((threshold & OPTIMIZER_BITS_MASK) == 0); + // Use '>=' not '>' so that the optimizer/backoff bits do not effect the result. // Double-check that the opcode isn't instrumented or something: - if (ucounter > threshold && this_instr->op.code == JUMP_BACKWARD) { + if (offset_counter >= threshold && this_instr->op.code == JUMP_BACKWARD) { OPT_STAT_INC(attempts); _Py_CODEUNIT *start = this_instr; /* Back up over EXTENDED_ARGs so optimizer sees the whole instruction */ @@ -2338,18 +2341,18 @@ dummy_func( // Rewind and enter the executor: assert(start->op.code == ENTER_EXECUTOR); next_instr = start; - this_instr[1].cache &= ((1 << OPTIMIZER_BITS_IN_COUNTER) - 1); + this_instr[1].cache &= OPTIMIZER_BITS_MASK; } else { - int backoff = this_instr[1].cache & ((1 << OPTIMIZER_BITS_IN_COUNTER) - 1); - if (backoff < MINIMUM_TIER2_BACKOFF) { - backoff = MINIMUM_TIER2_BACKOFF; + int backoff = this_instr[1].cache & OPTIMIZER_BITS_MASK; + backoff++; + if (backoff < MIN_TIER2_BACKOFF) { + backoff = MIN_TIER2_BACKOFF; } - else if (backoff < 15 - OPTIMIZER_BITS_IN_COUNTER) { - backoff++; + else if (backoff > MAX_TIER2_BACKOFF) { + backoff = MAX_TIER2_BACKOFF; } - assert(backoff <= 15 - OPTIMIZER_BITS_IN_COUNTER); - this_instr[1].cache = ((1 << 16) - ((1 << OPTIMIZER_BITS_IN_COUNTER) << backoff)) | backoff; + this_instr[1].cache = ((UINT16_MAX << OPTIMIZER_BITS_IN_COUNTER) << backoff) | backoff; } } #endif /* ENABLE_SPECIALIZATION */ |