[Mongrel] [WARN] Got 99% CPU?

[Zed A. Shaw]

On Tue, 24 Oct 2006 11:05:49 -0700
Michael Moen <mi-mongrel at moensolutions.com> wrote:

> Zed- We're seeing processes go off and become "dead", they continue  
> to accept connections, but the don't do anything useful.
> 
> We had manually applied your one-liner from r356 and the problem went  
> down quite a bit. We are still seeing an occasional process drift off  
> and now we are getting a trace in the log.
>

Go grab the 0.3.13.5 pre-release and run it under USR1 debugging in production.  It's got a tweak to the debugging output so that you can better understand what action is blocking the mongrel.  Something like this:

$ gem install mongrel --source=http://mongrel.rubyforge.org/releases
$ <start mongrel_rails however you do>
$ killall -USR1 mongrel_rails

Then, you're looking for lines in mongrel.log:

Tue Oct 24 15:07:07 PDT 2006: 0 threads sync_waiting for /test, 1 still active
in Mongrel.
 
> I'm responding to this here as it is a production site and a fairly  
> high volume one http://jibjab.com , but we are not seeing high CPU  
> usage, in fact the dead processes aren't using any to speak of.

Yep, this sounds like you have a particular Rails action that is blocking the process.  What kinds of things is your Rails application doing?

-- 
Zed A. Shaw, MUDCRAP-CE Master Black Belt Sifu
http://www.zedshaw.com/
http://mongrel.rubyforge.org/
http://www.lingr.com/room/3yXhqKbfPy8 -- Come get help.