PHP :: Request #68824 :: php-rpm pm=static causes load peaks when pm.max

php-rpm pm=static causes load peaks when pm.max_requests is reached

Submitted:

2015-01-13 11:29 UTC

Modified:

2021-12-04 21:12 UTC

Votes:	2
Avg. Score:	3.5 ± 0.5
Reproduced:	1 of 2 (50.0%)
Same Version:	1 (100.0%)
Same OS:	1 (100.0%)

From:

rainer-phpbugs at 7val dot com

Assigned:

bukka (profile)

Status:

Assigned

Package:

FPM related

PHP Version:

5.6.4

OS:

linux

Private report:

CVE-ID:

None

[2015-01-13 11:29 UTC] rainer-phpbugs at 7val dot com

Description:
------------
By design, php-fpm starts all pm.max_children at the same time, and therefore, will also re-start all children roughly at the same time when they reach  pm.max_requests. This causes the load on the Server, as well as latencies to increase until all children are re-started, their caches warmed up etc.

It would be preferable to randomize the number of requests until a child is reaped, instead of always using exactly pm.max_requests. For example, a random value within  pm.max_requests plus or minus 10% could be chosen for each child.

Patches

Pull Requests

History

[2015-01-13 17:58 UTC] aharvey@php.net

-Package: Performance problem +Package: FPM related

[2021-12-04 21:12 UTC] bukka@php.net

-Type: Bug +Type: Feature/Change Request -Assigned To: +Assigned To: bukka

[2021-12-04 21:12 UTC] bukka@php.net

This is the way how the accept scheduling works - this could be improved by using epoll which we might need for other things (e.g. bootstrapping) as well. See related discussion for more details in this pr (it is for ondemand but the actual loop is not mode dependent): https://github.com/php/php-src/pull/4101

I'm changing this to request as it is more feature request though.

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