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Subject: Re: Frequent wake-ups for mpm_event
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From: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Message-ID: <ae649ecd-715c-e464-77d9-48bd32467348@profihost.ag>
Date: Mon, 10 Oct 2016 22:01:54 +0200
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archived-at: Mon, 10 Oct 2016 20:02:15 -0000

Hi Luca,
Am 10.10.2016 um 16:48 schrieb Luca Toscano:
> Hi Stefan,
> 
> 2016-10-07 10:11 GMT+02:00 Stefan Priebe - Profihost AG
> <s.priebe@profihost.ag <mailto:s.priebe@profihost.ag>>:
> 
>     Am 05.10.2016 <tel:05.10.2016> um 12:50 schrieb Luca Toscano:
>     > Hi Stefan,
>     >
>     > 2016-09-26 14:26 GMT+02:00 Stefan Priebe - Profihost AG
>     > <s.priebe@profihost.ag <mailto:s.priebe@profihost.ag>
>     <mailto:s.priebe@profihost.ag <mailto:s.priebe@profihost.ag>>>:
>     >
>     >     currently no deadlocks since V5 also no old httpd processes anymore.
>     >
>     >
>     > if you still have patience and time, I'd like to ask you a question:
>     > have you noticed any performance improvement after applying the patch?
>     > For example (Yann correct me if I am wrong) I'd expect some reduction in
>     > system CPU utilization since the number of wake ups / context switches
>     > has been reduced dramatically. Moreover, it would be great to know some
>     > info about the status of the worker threads over time from the
>     > scoreboard, since it would be great not to introduce weird regressions
>     > with this patch :)
> 
>     Dear Luca,
> 
>     sure what can i exactly provide?
> 
> 
> I would be interested in scoreboard related metrics over time, namely if
> the number of busy/idle/graceful/etc.. worker statuses change from a
> "regular" 2.4.23 httpd. I don't expect a bit difference, but I'd really
> like to make sure that no big regression is introduced (like let's say,
> an increase over time of worker threads stuck in a certain status like G
> or more busy workers at request peak load time). 
> 
> Related to the above: have you noticed any improvement in
> latency/throughput metrics? For example, an improvement in total amount
> of requests handled in the same period of time o more generally in the
> responsiveness of the websites served?

It seems i cannot provide any of the requested data ;-(

This is an example output of a server running with the patch:
   Current Time: Monday, 10-Oct-2016 21:57:49 CEST
   Restart Time: Wednesday, 05-Oct-2016 06:30:31 CEST
   Parent Server Config. Generation: 12
   Parent Server MPM Generation: 11
   Server uptime: 5 days 15 hours 27 minutes 17 seconds
   Server load: 4.01 4.22 4.10
   Total accesses: 6485371 - Total Traffic: 139.0 GB
   CPU Usage: u2686.2 s1651.82 cu0 cs0 - .89% CPU load
   13.3 requests/sec - 298.9 kB/second - 22.5 kB/request
   10 requests currently being processed, 115 idle workers

   Slot  PID  Stopping   Connections    Threads      Async connections
                       total accepting busy idle writing keep-alive closing
   0    6044  no       8     yes       2    23   0       1          4
   1    15254 no       3     yes       2    23   0       0          2
   2    15189 no       5     yes       3    22   0       0          2
   3    15081 no       5     yes       0    25   0       0          4
   4    15082 no       1     yes       3    22   0       0          0
   Sum  5     0        22              10   115  0       1          12

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Stefan