Edit report at https://bugs.php.net/bug.php?id=75488&edit=1
ID: 75488
User updated by: david at davidfavor dot com
Reported by: david at davidfavor dot com
Summary: Under heavy load PHP misses Opcache hits with no
errors
Status: Open
Type: Bug
Package: opcache
Operating System: Ubuntu Artful
-PHP Version: 7.2.3
+PHP Version: 7.2.5
Block user comment: N
Private report: N
New Comment:
Bumping version to 7.2.5 as problem persists.
Previous Comments:
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[2018-05-07 14:12:53] david at davidfavor dot com
When Opcache is working correctly CPU usage should be near 0%, as only a lookup is done + code
returned.
When Opcache shows 100% load, Opcache is failing. This can easily be seen on machines running
massive disk I/O as the time required to load + compile PHP can be many seconds.
I'd expect Opcache to return 0% all the time, it it were working correctly.
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[2018-04-27 15:28:26] nikic@php.net
It's not immediately obvious to me that there is any bug here. Why do you think that any log
entry without 0.00% CPU usage indicates an opcache miss? Execution time and CPU load vary and your
99-percentile load is going to be significantly higher than your average load. Especially as opcache
itself only reports 2 misses, I'd assume that at least this particular case is simply due to
statistical variation.
Now, the actual production case you describe does look like an actual problem. This kind of behavior
should not occur during normal operation, but this would be fairly typical during an opcache
restart. Do these occurrences coincide with anything that could trigger an opcache reset (files
being deployed, fpm reloaded, etc.)?
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[2018-03-26 14:28:55] david at davidfavor dot com
Bug persists.
Bumping PHP level.
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[2018-03-07 13:51:23] david at davidfavor dot com
Problem still exists.
Bumping PHP + OS versions.
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[2018-01-15 16:06:45] david at davidfavor dot com
This is a huge problem for high traffic sites using PHP for dynamic content generation.
Be great if someone knowledgable about Opcache could take a look at this + determine a fix or work
around.
Thanks.
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