[Info-vax] Apache + mod_php performance

[Arne Vajhøj]

On 9/27/2024 4:50 PM, Dan Cross wrote:
> 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?

Yes.

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

I was referring the math 17 = 340 / 20.

There is nothing reasonable about those numbers.

Arne