random: Embed the Mt19937 and CombinedLCG state within the module globals#13579
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TimWolla merged 1 commit intophp:masterfrom Mar 4, 2024
Merged
random: Embed the Mt19937 and CombinedLCG state within the module globals#13579TimWolla merged 1 commit intophp:masterfrom
TimWolla merged 1 commit intophp:masterfrom
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These are always dynamically allocated in GINIT, thus always take up memory. By
embedding them here we can avoid the dynamic allocation and additional pointer
indirection accessing them.
The test script:
<?php
for ($i = 0; $i < 9999999; $i++) mt_rand(1, 100);
Appears to run slightly faster with this change applied: Before this change it
always ran in just over 3 seconds, after this change I was also seeing times
below 3 seconds. Howver results are too close and too jittery to state this
performance improvement as a fact.
zeriyoshi
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Mar 4, 2024
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I lacked this perspective at the time, very good!
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For reference: This fails with MSAN: https://github.com/php/php-src/actions/runs/8165488968/job/22322762350. I'll fix this tonight. |
TimWolla
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Mar 6, 2024
…lt_status()` This is a follow-up fix for phpGH-13579. The issue was detected in the nightly MSAN build.
TimWolla
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Mar 12, 2024
…lt_status()` (php#13608) This is not just an issue due to missing initialization since moving the state struct directly into the module globals. In earlier versions changing the mode to `MT_RAND_PHP` within a single request would also affect the mode for subsequent requests. Original commit message follows: This is a follow-up fix for phpGH-13579. The issue was detected in the nightly MSAN build. (cherry picked from commit bf0abd1)
TimWolla
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Mar 13, 2024
…lt_status()` (#13690) This is not just an issue due to missing initialization since moving the state struct directly into the module globals. In earlier versions changing the mode to `MT_RAND_PHP` within a single request would also affect the mode for subsequent requests. Original commit message follows: This is a follow-up fix for GH-13579. The issue was detected in the nightly MSAN build. (cherry picked from commit bf0abd1)
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Somewhat related to #13577
These are always dynamically allocated in GINIT, thus always take up memory. By embedding them here we can avoid the dynamic allocation and additional pointer indirection accessing them.
The test script:
Appears to run slightly faster with this change applied: Before this change it always ran in just over 3 seconds, after this change I was also seeing times below 3 seconds. Howver results are too close and too jittery to state this performance improvement as a fact.