Re: [squid-users] Memory and CPU usage squid-3.1.4

Martin.Pichlmaier_at_continental-corporation.com wrote:
> Hello list,
>
> I have a question regarding memory and CPU usage change from 3.0 to 3.1.
>
> I have 4 forwards proxies with ICAP (c-icap and clamav), NTLMv2
> authentication, all four proxies each have about 200-400 req/sec
> on RedHat AS5 64bit servers with each 16GB mem for about 15k to 30k users.
> cache_mem is set to 3.5 GB, no disk cache, some ACLs are used.
> With 3.0.STABLE23 the typical memory usage was about 7 GB and CPU usage of
> about 30-40% for the main squid process, without the helpers or other
> processes.
> With 3.1.4 the proxies use up to 2GB more memory and CPU usage rose at
> times to 60% or 80%.
> After a restart of one of the proxies it behaved "normally" since then.
>
> Status: (the CPU usage, Client HTTP out and requests per second are all
> from last 5 minute-info)
>
> Proxy1: 36% CPU 7.2 GB mem 3.3 MB/s client out 341 req/s
> Version 3.1.4
> Proxy2: 77% CPU 8.6 GB mem 2.6 MB/s client out 384 req/s
> Version 3.1.4 <-----
> Proxy3: 53% CPU 8.8 GB mem 6.8 MB/s client out 402 req/s
> Version 3.1.4
> Proxy4: 32% CPU 6.8 GB mem 2.7 MB/s client out 405 req/s
> Version 3.0.STABLE23
>
> Configuration of the proxies is the same, with only the changes for 3.1,
> mainly icap config.
>
> Is there some kind of memory leak that additionally causes massive CPU
> usage, could it be load related or is this normal behaviour?
>
> Martin

With an explicit cache_mem there should be no difference between the two.

Maybe; ICAP needs to buffer traffic twice as much as normal. One buffer
queue to ICAP server, one to client.

Maybe; with HTTP/1.1 being advertised now, if you have ignore_expect_100
turned on you can see the number of waiting clients rise. These are
active but 'hung' connections which waste more resources until the
client times out and continues.

Maybe; There are some known leaks in 3.0/3.1 auth. But that does not
account for the extra CPU unless it contributes to making the box swap
memory pages.

In general 3.1.4 has a lot of memory fixes than 3.0. Which are supposed
to cause less resource waste. Earlier 3.1.x default memory features were
broken on 64-bit. Check if turning memory pools on/off has any good effect.

Amos

-- 
Please be using
   Current Stable Squid 2.7.STABLE9 or 3.1.4