Fwd: FreeBSD 6.2-STABLE && apache 2.2.4 = bad performance. Help!

[Michael Vaughn]

On 7/19/07, Chuck Swiger <cswiger at mac.com> wrote:

> On Jul 18, 2007, at 3:12 PM, Michael Vaughn wrote:
> > Hello everyone,
>
> Hi--
>
> > I am contacting -performance, -questions, and -hackers in the hope
> > someone
> > helps me troubleshoot a problem with FreeBSD 6.2 and apache 2.2.4
>
> Please don't cross-post between multiple FreeBSD lists; pick the most
> appropriate one.
>
> [ ... ]
> > Right after starting apache, the loads on the server will climb to
> > 10-40's
> > and the application will become unacceptably slow. This will go on
> > until few
> > users are using the said application. (note: other servers running
> > older
> > FreeBSD versions on dual cpus running the same code don't exhibit this
> > system% problem) top shows more than 60% of the CPU time is spent
> > on system:
> >
> > CPU states: 19.9% user, 0.0% nice, 73.7% system, 1.7% interrupt,
> > 4.7% idle
> > Mem: 398M Active, 2226M Inact, 253M Wired, 202M Cache, 214M Buf,
> > 567M Free
> >
> > The apache processes look like:
> > PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
> > 56882 www 1 103 0 139M 17516K select 0 0:03 12.66% httpd
> > 56862 www 1 100 0 139M 21168K CPU2 6 0:06 11.87% httpd
> > 56830 www 1 99 0 138M 19684K select 2 0:09 10.76% httpd
> > 56887 www 1 105 0 139M 17488K select 6 0:01 10.49% httpd
> [ ... ]
>
> Your Apache processes are huge; mine typically stay under 20MB in
> VSIZE even with PHP loaded (this is Apache-2.0.59 + PHP 4.4.7 or PHP
> 5.2.x).  I suspect your PHP app(s) are leaking memory or otherwise
> have some significant problems with the way they are coded.
>



The SIZE is huge; What they really use is about 20-30Mb as would be
> expected.




> I had to lower MaxClients on apache substancially from 128 to 32,
> > or loads
> > would quickly go to 40+. (Other servers with dual cpus instead of
> > quad and
> > apache 1.3 on freebsd 6.0 don't have this problem)
>
> The fact that your server starts dogging out around 40 processes is
> not surprising-- 40 * ~140MB per httpd child = 5600 MB, which exceeds
> the available physical memory in the system, at which point you start
> swapping excessively and the performance is going to plummet.


Swap: 8000M Total, 8000M Free



You will have to find a way to make those httpd children smaller or
> else reduce the max number you run to 30 or less.


I have tried disabling pecl-APC and I already have most of the modules
commented out on
httpd.conf.

Nothing special running, other than php & extensions, and mod_security2. The
least I got was 70Mb per child.

> Now this web application isn't the best code out there, but this is
> > a quad
> > cpu server and it's performing a lot worse than some servers I have
> > running
> > with 6.0 with apache 1.3 for over 400 days.
> >
> > Am I the only one getting terrible performance with apache2 on
> > FreeBSD 6 ?
>
> Apache-2.0 + PHP does just fine for me; I'm not sure that Apache-2.2
> + PHP5 has been as well tested or is as lightweight in resources as
> the older Apache 1.3 or 2.0 flavors are.  It might be worth
> downgrading to an older Apache to test things out, but it really does
> sound like the web app you've got is the problem more than FreeBSD 6
> or the rest of your infrastructure....
>
> I might give 2.0 a go; I felt this was worth mentioning because most of
> the cpu time is spent on system, even with just 32 MaxClients.


 Do note I mentioned the same app runs on inferior, with loads of 0-4 (not
optimal, but there is no noticeable slowdown there) on FreeBSD 6.0/i386
apache 1.3 (this is 6.2-STABLE/amd64 apache 2.2.4), and that is also part of
the reason I went ahead and mailed the list. It doesn't make sense that a
server with twice the ram, twice the processors and a recent OS version is
spending 70% of the time in system% whereas the old servers running for 400+
days spend about 25% in system%.


Thanks for your reply.





Also

--
> -Chuck
>
>