https://bz.apache.org/bugzilla/show_bug.cgi?id=66424
Bug ID: 66424
Summary: CPU affinity request
Product: Apache httpd-2
Version: 2.4.37
Hardware: PC
OS: Linux
Status: NEW
Severity: major
Priority: P2
Component: mpm_event
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 38463
--> https://bz.apache.org/bugzilla/attachment.cgi?id=38463&action=edit
Diagram for cpu affinity setting
Hi All,
During httpd performance evaluation in Alibaba Cloud instance, I found httpd
performance improved significantly after using “taskset” to set CPU affinity
for httpd processes/threads, because it decreased the amount of CPU migrations.
Performance improved 60% in arm instance g8y.2xlarge(8 vcpus, 32GiB memory,
40GB ESSD), also improved 20% in x86 instance g7.2xlarge(8 vcpus, 32GiB memory,
40GB ESSD). Test case: run httpd with event mode on g8y.2xlarge or g7.2xlarge,
run traffic generator/benchmark 'wrk' on g8y.4xlarge(16 vcpus, 32GiB memory,
40GB ESSD), wrk command is 'wrk -t 32 -c 1000 -d 30 --latency http://$ServerIP'
mpm event parameters:
<IfModule mpm_event_module>
StartServers 8
ServerLimit 100
ThreadLimit 2000
MinSpareThreads 75
MaxSpareThreads 2000
ThreadsPerChild 125
MaxRequestWorkers 2000
</IfModule>
But httpd didn't have related parameters to support CPU affinity, so I used
"taskset" to optimize. After source code analysis, I made a prototype for the
affinity solution(add set_affinity function when worker/lister thread created).
We can observed the same improvement by this solution. However, this prototype
only applied on above special “event mpm” configuration. I think also need to
modify current mechanism of dynamically adapts to the perceived load and add
new parameters for the affinity setting.
So is it possible to involve httpd developer to evaluate this request and add
cpu affinity function in future version?
Thanks
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