[Mono-devel-list] High CPU utilization when running mod_mono/xsp

[Jaroslaw Kowalski]

I get very high CPU load when running mod_mono/xsp even when no pages are
served. As I run without NPTL I have 5 processes named mod-mono-server.exe,
each taking about 20% CPU time. Load average exceeds "5.0".

This applies to current mono/CVS. After I "strace'd" it, I got a massive
amount of this:

gettimeofday({1087367416, 4291901250}, NULL) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [RTMIN], 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN], [RTMIN], 8) = 0
gettimeofday({1087367416, 4291906635}, NULL) = 0
rt_sigprocmask(SIG_SETMASK, [RTMIN], NULL, 8) = 0
gettimeofday({1087367416, 4291906687}, NULL) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [RTMIN], 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN], [RTMIN], 8) = 0
gettimeofday({1087367416, 4291906760}, NULL) = 0
rt_sigprocmask(SIG_SETMASK, [RTMIN], NULL, 8) = 0
gettimeofday({1087367416, 4291906802}, NULL) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [RTMIN], 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN], [RTMIN], 8) = 0
gettimeofday({1087367416, 4291906871}, NULL) = 0
rt_sigprocmask(SIG_SETMASK, [RTMIN], NULL, 8) = 0
gettimeofday({1087367416, 4291906913}, NULL) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [RTMIN], 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN], [RTMIN], 8) = 0
gettimeofday({1087367416, 4291906982}, NULL) = 0
rt_sigprocmask(SIG_SETMASK, [RTMIN], NULL, 8) = 0

Notice that it get's called many times a second (I suspect an active waiting
somewhere).
I could provide more debug info, but I've got no idea how to attach a
debugger and break all threads to see which function causes this flood. In
VS.NET this would be simple but "gdb" scares me. I'd be glad if someone
could provide a step-by-step guide for running gdb to capture this
information.

Jarek

P.S. This may be related to the fact that I'm running this instance on
mod_mono/xsp on colinux (http://www.colinux.org) under Windows 2003 host. I
may be wrong, but this is about 5th mod_mono on coLinux that I'm trying and
I never experienced high load like this.