[Info-vax] Apache + mod_php performance

[Dan Cross]

In article <vd745a$q3hr$3 at dont-email.me>,
Arne Vajhøj  <arne at vajhoej.dk> wrote:
>On 9/27/2024 4:13 PM, Dan Cross wrote:
>> In article <vd73ho$q3hr$2 at dont-email.me>,
>> Arne Vajhøj  <arne at vajhoej.dk> wrote:
>>> On 9/27/2024 3:40 PM, Dan Cross wrote:
>>>> In article <66f70712$0$711$14726298 at news.sunsite.dk>,
>>>> Arne Vajhøj  <arne at vajhoej.dk> wrote:
>>>>> On 9/27/2024 3:16 PM, Dan Cross wrote:
>>>>>> In article <vd6l5h$pmt5$1 at dont-email.me>,
>>>>>> Arne Vajhøj  <arne at vajhoej.dk> wrote:
>>>>>>> On 9/26/2024 11:44 AM, Dan Cross wrote:
>>>>>>>> In article <vd1u8j$3qqpg$1 at dont-email.me>,
>>>>>>>> Arne Vajhøj  <arne at vajhoej.dk> 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.
>>>>>>>>
>>>>>>>> My guess is that communications overhead is slowing things down.
>>>>>>>> What happens if you set these super low, ideally so there's a
>>>>>>>> single process handling requests, then see what sort of QPS
>>>>>>>> numbers you get for your trivial text file.
>>>>>>>
>>>>>>> I set it down to 1.
>>>>>>>
>>>>>>> 0.1 req/sec
>>>>>>
>>>>>> So a single request takes 10 seconds?  Or you can only make one
>>>>>> request every 10 seconds, but the time taken to process that
>>>>>> request is relatively small?
>>>>>
>>>>> It is throughput.
>>>>>
>>>>> N / time it takes to get response for N requests
>>>>>
>>>>> With 20 threads in client then there will always be 20 outstanding
>>>>> requests.
>>>>
>>>> How long does it take to serve a single request?
>>>
>>> Based on the above information it should be 200 seconds.
>>>
>>> But it is actually more like 340 seconds. So apparently the 0.1
>>> req/sec is rounded up a bit.
>> 
>> Ok, just to clarify, you hit the web server with a single
>> request for a small static resource, while no other traffic was
>> hitting it, and that request took more than _five minutes_ to
>> complete?
>
>340 seconds is with 20 client threads.
>
>With 1 client thread time is 17 seconds.

So again, to clarify, the time to issue one request against an
otherwise idle server and retrieve a small amount of static data
in response to that request is 17 seconds?

>As expected.

It is always good to verify.  I might add that there's no
relevant environment where that's a reasonable expectation.

	- Dan C.