Re: Apache + mod_php performance

On 9/27/2024 8:38 PM, Dan Cross wrote:

In article <vd7hbi$tgu3$2@dont-email.me>,
Arne Vajhøj  <arne@vajhoej.dk> wrote:

On 9/25/2024 5:10 PM, Arne Vajhøj wrote:

It must be Apache.
>
Apache on VMS is prefork MPM. Yuck.
>
MaxSpareServers 10 -> 50
MaxClients 150 -> 300
>
actually did improve performance - double from 11 to 22
req/sec.
>
But the system did not like further increases. And besides
these numbers are absurd high to handle a simulator doing requests
from just 20 threads.
>
But not sure what else I can change.

>
And we have a solution.
>
httpd.conf
>
KeepAlive On
->
KeepAlive Off
>
And numbers improve dramatically.

>
Hmm. You had already said that you were _Not_ using keep alives
because that would somehow mimic multiple machines querying
simultaneously.

>
That is correct.
>
The client was not using keep alive.
>
But the server was configured to support keep alive.
>
Turning that capability off on the server solved the performance
problem.
>
No changes on client.
>
No keep alive used before - no keep alive used after.
>
Just disabling the capability on the server.
>

This was, of course, the area of investigation I had suggested
to you previously to try and nail down the baseline.  I question
whether this will impact your single query latency, however, or
whether this is masking it in your benchmark.
>

nop.txt 281 req/sec
nop.php 176 req/sec
real PHP no db con pool 94 req/sec
real PHP db con pool 103 req/sec
>
Numbers are not great, but within acceptable.

>
What is your single query latency?  Not calculated, but
actually measured.

>
It is a rather uninteresting number.
>
But easy to test. It obviously vary a bit, but they
are all in the 50-100 millisecond range.
>

It is a bug in the code.

>
The evidence in hand is insufficient to make that claim.

>
I believe that server config supporting keep alive
causing performance to drop to 1/10'th for clients
not using keep alive is a bug.
>
Arne
>