Re: [squid-users] Squid Memory and Page Faults

On 25/07/2013 10:01 a.m., Golden Shadow wrote:
> Thanks Amos, Eliezer and Markus for your replies!
>
> @Eliezer: The server has 2 X 2.7 GHz CPUs, each with 12 cores. Squid version is 3.3.7 compiled from source and I'm running only one squid worker.
>
> @Marcus: What is maximum process size that TLB can address? Is it tunable? My operating system is CENTOS 6.4 with Kernel 2.6.34.
>
> @Amos: Please see my comments below:
>
>
> ----- Original Message -----
> From: Amos Jeffries <squid3_at_treenet.co.nz>
> To: squid-users_at_squid-cache.org
> Cc:
> Sent: Wednesday, July 24, 2013 9:58 PM
> Subject: Re: [squid-users] Squid Memory and Page Faults
>
> On 25/07/2013 1:05 a.m., Golden Shadow wrote:
>>> Hi there!
>>>
>>> My squid is installed on a server with 192 GB of RAM. I have the following directives in squid.conf:
>>>
>>> cache_mem 143360 MB
>>> maximum_object_size_in_memory 300 KB
>>> memory_replacement_policy heap GDSF
>>>
>>> memory_pools on
>>> memory_pools_limit 1024 MB
>>>
>>> ipcache_size 2048
>>> ipcache_low 90
>>> ipcache_high 95
>>>
>>> fqdncache_size 2048
>>>
>>>
>>>
>>> top reports that my squid process size is 20GB, which is far less than my RAM size,
>>> but nevertheless I still find some page faults (about 70 page faults over 2 hours).
>>> I'm wondering how could those page faults are occurring while squid process size is far
>>> less than my RAM size. How can I eliminate those time consuming page faults?
>> Two things here.
>>
>> Why is the process size only 20GB? you have a 143GB memory cache as part
>> of that RAM consumption by Squid. Perhapse your traffics real caching
>> requirement is far smaller than you are allowing storage for.
> Well, according to cache manager my squid RSS reached 173 GB at some time!

Okay. That makes a lot more sense.

>
>> What exactly is the page faulting comign from though ... Squid or the OS?
> How can I tell? Cache manager itself reports these page faults, so I guess they are coming from squid.

Hmm. Not sure exactly been so long since I've seen one. But IIRC it was
recorded as part of the message. eg. (timestamp, source, err message)

Markus mention of TLS might be a better clue than I'm provide though.

Amos
Received on Thu Jul 25 2013 - 04:19:10 MDT