[squid-users] High cpu usage by re_search_internal

[Amos Jeffries]

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On 5/10/2014 3:34 a.m., Omid Kosari wrote:
> Mehdi Sarmadi wrote
>> Hey
>> 
>> Alright. About refresh pattern you have a very excessive list
>> IMHO. I don't know about your hardware but generally for a
>> typical general purpose SMB server hardware, that's too much. If
>> you want to stick with it and can't reduce the list. Check, how
>> many core's you machine have. You should know squid naturally 
>> sticks . A solution is to start multiple squid instances, that
>> way you can have squid(refresh_pattern) load distributed on more
>> than one CPU core, thus you'll get better performance.
>> 
>> Hope it helps Cheers
> 
> Thanks for the tip . It has a core i3 cpu so it has 4 cores .
> Unfortunately squid does not load fine across all cores specially
> in older versions like mine v 3.1 . Multi instance has its  own
> complexity and headaches . i am trying to have clean design to be
> away from those problems . It was very useful if squid could do the
> refresh_pattern jobs by other cores . or some trick like that .
> 

Here are some tips for your patterns:

* all the (.+\.)? at the begining are useless complication. Remove.

* so are the .*?$ at the end of some patterns. This bit is also
probably doing more harm than good. Because the $ hints to regex that
it should scan right-to-left and the path and query portions of the
URL is the largest pieces to scan over. Remove.

* the following two lines are redundant. The first will match
everything the second would have caught. Drop the second one.

  refresh_pattern -i \.htm 120 50% 10080 reload-into-ims
  refresh_pattern -i \.html 120 50% 10080 reload-into-ims

* the pattern below the comment "#Very aggressive 120 Days" contains
duplicates.


there are probably some smaller fixes, but those are the biggest I can
see without suggesting you drop those patterns entirely.

You would do well from an upgrade of Squid. The later versions have
eliminated the need for ignore-no-cache, ignore-private, ignore-auth
(the latter two there do really, really bad things).

I am also curios why you are ignoring must-revalidate? it is a
bandwidth reduction mechanism.

Amos
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