Date: Fri, 12 Sep 2008 23:44:51 +0200 From: "Ivan Voras" <ivoras@freebsd.org> To: "Alfred Perlstein" <alfred@freebsd.org> Cc: freebsd-threads@freebsd.org Subject: Re: Apache-worker stuck at 100% CPU Message-ID: <9bbcef730809121444u34991c52m2cbc01a8ada47eb5@mail.gmail.com> In-Reply-To: <20080912165808.GE16977@elvis.mu.org> References: <gadgrb$4uc$1@ger.gmane.org> <20080912165808.GE16977@elvis.mu.org>
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2008/9/12 Alfred Perlstein <alfred@freebsd.org>: > Try using "pstack" a few times. It's in ports. > > Also, gcore(1) might help. Will try. > You can also try to attach using gdb. I did, but either I'm missing something or I'm not using it well, because I can't get a backtrace. How do I select threads to backtrace? How do I pick what thread to backtrace? > Basically, one of these tools should give you a stack trace which > can help. > > It's interesting that the process is in "umtxn" though, is it > multithreaded apache? Can you dump the threads? I think top(1) > has an option to view each thread, how about trying that? Yes, it's multithreaded apache. This did help somewhat - when I do it I see that it's not actually stuck in umtxn - there's one thread that consumes the CPU and it's apparently always running (in state CPUx). PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU COMMAND 7212 www 103 0 30340K 7932K CPU2 2 444:23 99.02% httpd I'm currently upgrading the system to 7-STABLE, to see if it helps.
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