[Catalyst] Re: memory usage of mod_perl process

[Jeffrey Ng]

On 2/9/07, Perrin Harkins <pharkins at gmail.com> wrote:
>
> On 2/8/07, Jeffrey Ng <jeffreyn at gmail.com> wrote:
> > I have read practical mod_perl. I tried to preload many of our modules
> in
> > startup.pl. But the shared memory value doesnt change at all. Also,
> doesnt
> > 5.7M shared memory usage sound too small comparing to the 92.6M total
> size?
>
> You're not looking at the right thing there.  This is not actual
> shared memory, but rather copy-on-write sharing.  It will never show
> in your SHARE section.  On versions of Linux with a 2.6 kernel, you
> can use the techniques in Apache::SizeLimit to get a sesne of how much
> sharing is going.  This doesn't work with older kernels.
>
> A reliable way to tell if your sharing is improved is to start up
> apache without preloading and look at the available memory from
> "free", and then put in the preloading and restart apache and check it
> again.  You should have more free memory after preloading, allowing
> you to run more processes.


when i run this "free" test, should i run it on the live server, or on a
test server with single process apache mode?

here's the result on a live server:

             total       used       free     shared    buffers     cached
Mem:       4150972    2654016    1496956          0      27548    1313344
-/+ buffers/cache:    1313124    2837848
Swap:      8385912       6920    8378992


and here's the top results on one of the server:

top - 14:21:55 up 144 days,  9:30,  0 users,  load average: 19.30, 18.65,
12.27
Tasks:  87 total,   1 running,  86 sleeping,   0 stopped,   0 zombie
Cpu(s): 69.6% us,  1.3% sy,  0.0% ni, 27.7% id,  0.0% wa,  0.2% hi,  1.2% si
Mem:   4150972k total,  2623968k used,  1527004k free,    27380k buffers
Swap:  8385912k total,     6920k used,  8378992k free,  1312832k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
26343 apache    15   0 97196  83m 6236 S 10.0  2.1   0:08.69 httpd
26340 apache    15   0 94740  81m 5896 S  7.8  2.0   0:07.62 httpd
26315 apache    15   0 95552  81m 5896 S  7.4  2.0   0:08.31 httpd
26326 apache    15   0 94836  81m 5868 S  7.4  2.0   0:08.17 httpd
26371 apache    15   0 95496  81m 5872 S  7.4  2.0   0:08.21 httpd


I set the maxserver as 60.
Our CPU load is extremely high. But the actual RAM usage is not high at all.
we are using only 260 gig out of 400 gig. From our top results, does it look
like the memory usage of our processes is the bottleneck?

- Perrin
>
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-- =

Jeffrey Ng
CEO, Zorpia.com
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