Re: Random latency in reentrant calls (Bug 57916)

[Luc Andre <landre3567@xxxxxxxxx>]

My mistake, apache2.conf is overridden by  /mods-enabled/mpm_prefork.conf

sorry about that...

On Tue, May 12, 2015 at 12:03 PM, Luc Andre <landre3567@xxxxxxxxx> wrote:

php_sapi_name: apache2handler

Server MPM:     prefork

I tried 

    StartServers          20

    MinSpareServers       20

    MaxSpareServers      20

And after restarting apache still have the issue but only after waiting about a minute between 2 tries.

Then I did a "ps -ef | grep apache" and I discovered that I have only 11 apache processes running !

So it seems that MinSpareServers and StartServers  are ignored and the problem is really a child spin up issue.

Regards,

Luc

On Tue, May 12, 2015 at 11:16 AM, Rainer Canavan <rainer.canavan@xxxxxxxxxxxx> wrote:

2015-05-12 10:03 GMT+02:00 Luc Andre <landre3567@xxxxxxxxx>:

Thanks for your reply.

We did a test on a powerful server with 

    StartServers          20

    MinSpareServers       5

    MaxSpareServers      20

And we still have the issue...

To ensure that you don't hit the child spin up issue, you'll have to set  MinSpareServers to a value equal to or greater than the number of processes you need for your test, I'd recommend 20 in this case, just to be sure. Are you sure that you're using the prefork mpm, and therefore those settings are actually relevant? If you don't have a good reason to use prefork, you may get better performance with worker or event (but be sure to tune the associated settings, such as ThreadsPerChild appropriately)

Additionally, you don't specify how your PHP is configured. If you're using PHP-FPM, you need to ensure that pm.start_servers and pm.min_spare_servers are large enough as well. 

rainer