Implement an SSE2 accelerated version of zend_adler32 to speedup startup time for the file cache #10507
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When benchmarking the file cache of opcache on index.php from a dummy WordPress install, I noticed that 36.42% of the time was spent in zend_adler32 to verify the checksums of the files. Callgrind reported that 332,731,216 instructions were executed during that run and average time to execute the index file was around 91ms. This patch implements an SSE2 accelerated version of zend_adler32, which reduces the number of instructions executed on that bench to 248,600,983, which is a reduction of ~25%. There is also a decrease in wallclock time measurable: around 10ms. Now only 16.05% of the time is spent computing checksums. The benchmark tests were performed using Callgrind, and time for the wallclock time. These tests were executed multiple times and their results were averaged. The WordPress install only contains two almost-blank posts.
alexdowad
reviewed
Feb 5, 2023
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This looks sensible but would like @alexdowad to have a look at it as he has a better understanding of SSE2 then I do :) |
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I don't know the |
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When benchmarking the file cache of opcache on index.php from a dummy WordPress install, I noticed that 36.42% of the time was spent in zend_adler32 to verify the checksums of the files. Callgrind reported that 332,731,216 instructions were executed during that run and average time to execute the index file was around 91ms.
This patch implements an SSE2 accelerated version of zend_adler32, which reduces the number of instructions executed on that bench to 248,600,983, which is a reduction of ~25%. There is also a decrease in wallclock time measurable: around 10ms. Now only 16.05% of the time is spent computing checksums.
The benchmark tests were performed using Callgrind, and time for the wallclock time. These tests were executed multiple times and their results were averaged. The WordPress install only contains two almost-blank posts.