[squid-users] squid centos and osq_lock

[Amos Jeffries]

On 31/07/2015 8:05 a.m., Josip Makarevic wrote:
> Hi,
> 
> I have a problem with squid setup (squid version 3.5.6, built from source,
> centos 6.6)
> I've tried 2 options:
> 1. SMP
> 2. NON-SMP
> 
> I've decided to stick with custom build non-smp version and the thing is:
> - i don't need cache - any kind of it

 cache_mem 0
 cache deny all

That is it. All other caches used by Squid *are* mandatory for good
performance. And are only used anyway when the component that needs them
is actively used.


> - I have DNS cache just for that
> - squid has to listen on 1024 ports on 23 instances.
> each instance listens on set of ports and each port has different outgoing
> ip address.

And how many NIC do you have that spread over?

> 
> The thing is this:
> It's alll good until we hit it with more than 150mbits then...
> 
> (output from perf top)
>  84.57%  [kernel]                  [k] osq_lock
>   4.62%  [kernel]                  [k] mutex_spin_on_owner
>   1.41%  [kernel]                  [k] memcpy
>   0.79%  [kernel]                  [k] inet_dump_ifaddr
>   0.62%  [kernel]                  [k] memset
> 
>  21:53:39 up 7 days, 10:38,  1 user,  load average: 24.01, 23.84, 23.33
> (yes, we have 24 cores)
> Same behavior is with SMP and NON-SMP setup (SMP setup is all in one file
> with workers 23 option but then I have to use rock cache)
> 
> so, my question is....what...how to optimize this.....whatever....I'm stuck
> for days, I've tried many sysctl options but none of them works.
> Any help, info, something else?

None of those are Squid functionality. If you want help optimizing your
config and are willing to post it to the list I am happy to do a quick
audit and point out any problem areas for you.

But tuning the internal locking code of the kernel is way off topic.

Amos