hanging CPU-sucking httpd procs that say "..reading.."

[Jeff Ambrosino <jb...@gmail.com>]

Hi mod_perl folks,

I'm getting occasional hanging httpd children (prefork) that suck up
alot of CPU and
bog down my server. When I inspect Apache Status (ExtendedStatus On), I see
something like this:

434-3 11031 0/29/612 R  0.49 1341 0 0.0 0.20 4.09  ? ? ..reading.. 

There's no client IP, no virtual host, and no URI, just "..reading.."
Since these hung
procs don't die off by themselves, I'm thinking of setting up
Apache::Watchdog.  But,
before I resort to this, I'd like to do some more investigation to see
if I can't find and
fix the source of the problem.  Unfortunately this is a production server so I
can't do anything too intrusive.  Any suggestions for where to look or
other ways
to debug/diagnose this problem?

FYI I'm using httpd-2.0.54, mp2.0.0-RC4, libapreq2-2.04_03-dev.

thanks,
JB

Re: hanging CPU-sucking httpd procs that say "..reading.."

[Jeff Ambrosino <jb...@gmail.com>]

Not one to leave myself hanging :), I thought I'd update the group
before I switch
venues...  I've narrowed this problem to SSL requests only, and httpd is hanging
during the request read.  I use a PerlPostReadRequestHandler (which
has been helpful
in scoping the problem via a USR2 signal trap), but it turns out httpd
isn't even
getting that far...  the httpd child hangs somewhere before the
scorecard changes
from "..reading.." status.  Could be a locking/semaphore issue... My next debug
attempt (I'm waiting for the problem to recur) will be using gdb to
get some backtraces
and then head over to http-dev and/or mod_ssl lists.  Any last-ditch advice from
MP folks would be welcome, but not expected since this doesn't appear
to be a MP/Perl
issue (although it could be libapreq since I believe mod_ssl uses that.)

thanks
Jeff


On 9/8/05, Jeff Ambrosino <jb...@gmail.com> wrote:
> Sorry, I should have mentioned that I'm using a reverse mod_proxy, so
> the "hanging" is most likely during the http response from the
> back-end web server.  I realize this may not be a MP2 problem, but
> figured I'd at least start here on the mod_perl list since my entire
> app is an http output filter that processes the proxied response (and
> unfortunately the mod_proxy list is basically dead).
> 
> thanks
> JB
> 
> 
> On 9/8/05, Jeff Ambrosino <jb...@gmail.com> wrote:
> > Hi mod_perl folks,
> >
> > I'm getting occasional hanging httpd children (prefork) that suck up
> > alot of CPU and
> > bog down my server. When I inspect Apache Status (ExtendedStatus On), I see
> > something like this:
> >
> > 434-3 11031 0/29/612 R  0.49 1341 0 0.0 0.20 4.09  ? ? ..reading..
> .................
> > FYI I'm using httpd-2.0.54, mp2.0.0-RC4, libapreq2-2.04_03-dev.
> >
> > thanks,
> > JB
> >
>

Re: hanging CPU-sucking httpd procs that say "..reading.."

[Jeff Ambrosino <jb...@gmail.com>]

Sorry, I should have mentioned that I'm using a reverse mod_proxy, so
the "hanging" is most likely during the http response from the
back-end web server.  I realize this may not be a MP2 problem, but
figured I'd at least start here on the mod_perl list since my entire
app is an http output filter that processes the proxied response (and
unfortunately the mod_proxy list is basically dead).

thanks
JB


On 9/8/05, Jeff Ambrosino <jb...@gmail.com> wrote:
> Hi mod_perl folks,
> 
> I'm getting occasional hanging httpd children (prefork) that suck up
> alot of CPU and
> bog down my server. When I inspect Apache Status (ExtendedStatus On), I see
> something like this:
> 
> 434-3 11031 0/29/612 R  0.49 1341 0 0.0 0.20 4.09  ? ? ..reading..
.................
> FYI I'm using httpd-2.0.54, mp2.0.0-RC4, libapreq2-2.04_03-dev.
> 
> thanks,
> JB
>