Hi!

Thank you very much for the patches. Looks like they helped.

2018-03-29 14:25 GMT+05:00 Christopher Faulet <cfau...@haproxy.com>:

> Le 28/03/2018 à 14:16, Максим Куприянов a écrit :
>
>> Hi!
>>
>> I'm sorry but configuration it's too huge too share (over 100 different
>> proxy sections). This is also the reason I can't exactly determine the
>> failing section. Is there a way to get this data from core-file?
>>
>> 2018-03-28 11:18 GMT+03:00 Christopher Faulet <cfau...@haproxy.com
>> <mailto:cfau...@haproxy.com>>:
>>
>>     Le 28/03/2018 à 09:36, Максим Куприянов a écrit :
>>
>>         Hi!
>>
>>         Yesterday one of our haproxies (1.8.5) with nbthread=8 set in
>>         its config stuck with 800% CPU usage. Some responses were served
>>         successfully but many of them just timed out. perf top showed
>> this:
>>            59.19%  [.] thread_enter_sync
>>            32.68%  [.] fwrr_get_next_server
>>
>>
>>     Hi,
>>
>>     Could you share your configuration please ? It will help to diagnose
>>     the problem. In your logs, what is the values of srv_queue and
>>     backend_queue fields ?
>>
>>
> Hi,
>
> Ok, I partly reproduce your problem using a backend, with an hundred
> servers and a maxconn to 2 for each one. In this case, I observe same CPUs
> consumption. I have no timeouts (it probably depends on your values) but
> performances are quite low.
>
> I think you're hitting a limitation of the current design. We have no
> mechanism to migrate entities between threads. So to force threads wakeup,
> we use the sync point. It was not designed to be called very often. In your
> case, it eats all the CPU.
>
> I attached 3 patches. They add a mechanism to wakeup threads selectively
> without any lock or loop. They must be applied on HAProxy 1.8 (it will not
> work on the upstream). So you can check if it fixes your problem or not. It
> will be useful to validate it is a design limitation and not a bug.
>
> This is just an experimentation. I hope it works well but I didn't do a
> lot of testing. If yes, I'll then discuss with Willy if it is pertinent or
> not to do the threads wakeup this way. But, in all cases, it will probably
> not be backported in HAProxy 1.8.
>
> --
> Christopher Faulet
>

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