"Vincent Sweeney" <v.sweeney@barrysworld.com> wrote:
> > > > CPU0 states: 27.2% user, 62.4% system, 0.0% nice, 9.2% idle
> > > > CPU1 states: 28.4% user, 62.3% system, 0.0% nice, 8.1% idle
> > >
> > > The important bit here is ^^^^^^^^ that one. Something is causing
> > > horrendous lock contention it appears.
> ...
> Right then, here is the results from today so far (snapshot taken with 2000
> users per ircd). Kernel profiling enabled with the eepro100 driver compiled
> statically.
> readprofile -r ; sleep 60; readprofile | sort -n | tail -30
> ...
> 170 sys_poll 0.1897
> 269 do_pollfd 1.4944
> 462 remove_wait_queue 12.8333
> 474 add_wait_queue 9.1154
> 782 fput 3.3707
> 1216 default_idle 23.3846
> 1334 fget 16.6750
> 1347 sock_poll 33.6750
> 2408 tcp_poll 6.9195
> 9366 total 0.0094
> ...
> So with my little knowledge of what this means I would say this is purely
> down to poll(), but surely even with 4000 connections to the box that
> shouldn't stretch a dual P3-800 box as much as it does?
My oldish results,
http://www.kegel.com/dkftpbench/Poller_bench.html#results
show that yes, 4000 connections can really hurt a Linux program
that uses poll(). It is very tempting to port ircd to use
the Poller library (http://www.kegel.com/dkftpbench/dkftpbench-0.38.tar.gz);
that would let us compare poll(), realtimesignals, and /dev/epoll
to see how well they do on your workload.
- Dan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Thu Jan 31 2002 - 21:01:05 EST