Date: Sun, 20 Jun 2004 20:12:46 -0400 (EDT) From: Robert Watson <rwatson@FreeBSD.org> To: threads@FreeBSD.org Cc: current@FreeBSD.org Subject: Re: calcru: negative time ... followed by freeze Message-ID: <Pine.NEB.3.96L.1040620201200.5500E-100000@fledge.watson.org> In-Reply-To: <Pine.NEB.3.96L.1040620200617.5500D-100000@fledge.watson.org>
next in thread | previous in thread | raw e-mail | index | archive | help
FYI, this is a Xeon box with two physical processors, each with two logical processors, and the problem could well be SMP-related. Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Senior Research Scientist, McAfee Research On Sun, 20 Jun 2004, Robert Watson wrote: > > I've now seen the following scenario happen several times in the last few > days while doing testing and benchmarking: I run a multi-threaded test, > such as super-smack, that causes a moderately high system load. I then > hit Ctrl-T or run top, or some other activity that forces calcru() to > execute. I will not infrequently get an extremely hard hang -- can't get > to DDB using serial break, etc. I don't remember it happening when using > non-threaded apps, so I'm wondering if there's a poor interaction with > KSE/scheduler/who knows what. > > 7:55PM up 6 mins, 2 users, load averages: 1.37, 0.91, 0.43 > USER TTY FROM LOGIN@ IDLE WHAT > root d0 - 7:55PM - w > rwatson p0 cboss 7:50PM 2 super-smack > select-key > hippy# top > calcru: negative time of 1834075 usec for pid 654 (super-smack) > ca~~ > > In this case, I ran super-smack with the following parameters: > > hippy:/usr/tmp/super-smack> super-smack select-key.smack 15 1000 > > This generates 15 workers, which should cause mysql to spawn off threads > as well. I'm running with stock libpthread on this system (slightly old) > but an up-to-date kernel from CVS, GENERIC. > > Has anyone else seen this? > > Robert N M Watson FreeBSD Core Team, TrustedBSD Projects > robert@fledge.watson.org Senior Research Scientist, McAfee Research > >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.NEB.3.96L.1040620201200.5500E-100000>