[New-bugs-announce] [issue45527] Reduce overhead for cache hits in specialized opcodes.

[Mark Shannon]

New submission from Mark Shannon <mark at hotpy.org>:

Every time we get a cache hit in, e.g. LOAD_ATTR_CACHED, we increment the saturating counting. Takes a dependent load and a store, as well as the shift. For fast instructions like BINARY_ADD_FLOAT, this represents a significant portion of work done in the instruction.

If we don't bother to record the hit, we reduce the overhead of fast, specialized instructions.

The cost is that may have re-optimize more often.
For those instructions with high hit-to-miss ratios, which is most, this be barely measurable.
The cost for type unstable and un-optimizable instruction shouldn't be much changed.

Initial experiments show ~1% speedup.

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assignee: Mark.Shannon
components: Interpreter Core
messages: 404320
nosy: Mark.Shannon
priority: normal
severity: normal
status: open
title: Reduce overhead for cache hits in specialized opcodes.
type: performance
versions: Python 3.11

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue45527>
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