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author | Guido van Rossum <guido@python.org> | 2024-04-04 15:03:27 (GMT) |
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committer | GitHub <noreply@github.com> | 2024-04-04 15:03:27 (GMT) |
commit | 060a96f1a9a901b01ed304aa82b886d248ca1cb6 (patch) | |
tree | cb3e95ecac1f90440b7d3752c4aad015ea734bf0 /Python/specialize.c | |
parent | 63bbe77d9bb2be4db83ed09b96dd22f2a44ef55b (diff) | |
download | cpython-060a96f1a9a901b01ed304aa82b886d248ca1cb6.zip cpython-060a96f1a9a901b01ed304aa82b886d248ca1cb6.tar.gz cpython-060a96f1a9a901b01ed304aa82b886d248ca1cb6.tar.bz2 |
gh-116968: Reimplement Tier 2 counters (#117144)
Introduce a unified 16-bit backoff counter type (``_Py_BackoffCounter``),
shared between the Tier 1 adaptive specializer and the Tier 2 optimizer. The
API used for adaptive specialization counters is changed but the behavior is
(supposed to be) identical.
The behavior of the Tier 2 counters is changed:
- There are no longer dynamic thresholds (we never varied these).
- All counters now use the same exponential backoff.
- The counter for ``JUMP_BACKWARD`` starts counting down from 16.
- The ``temperature`` in side exits starts counting down from 64.
Diffstat (limited to 'Python/specialize.c')
-rw-r--r-- | Python/specialize.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/Python/specialize.c b/Python/specialize.c index f1e32d0..0b4b199 100644 --- a/Python/specialize.c +++ b/Python/specialize.c @@ -419,22 +419,20 @@ _PyCode_Quicken(PyCodeObject *code) int caches = _PyOpcode_Caches[opcode]; if (caches) { // The initial value depends on the opcode - int initial_value; switch (opcode) { case JUMP_BACKWARD: - initial_value = 0; + instructions[i + 1].counter = initial_jump_backoff_counter(); break; case POP_JUMP_IF_FALSE: case POP_JUMP_IF_TRUE: case POP_JUMP_IF_NONE: case POP_JUMP_IF_NOT_NONE: - initial_value = 0x5555; // Alternating 0, 1 bits + instructions[i + 1].cache = 0x5555; // Alternating 0, 1 bits break; default: - initial_value = adaptive_counter_warmup(); + instructions[i + 1].counter = adaptive_counter_warmup(); break; } - instructions[i + 1].cache = initial_value; i += caches; } } |