Date: Tue, 16 Oct 2007 02:42:46 +0200 From: Kris Kennaway <kris@FreeBSD.org> To: Alexey Popov <lol@chistydom.ru> Cc: freebsd-hackers@freebsd.org, freebsd-stable@freebsd.org Subject: Re: amrd disk performance drop after running under high load Message-ID: <47140906.2020107@FreeBSD.org> In-Reply-To: <47137D36.1020305@chistydom.ru> References: <47137D36.1020305@chistydom.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
Alexey Popov wrote: > After some time of running under high load disk performance become > expremely poor. At that periods 'systat -vm 1' shows something like this: What does "high load" mean? You need to explain the system workload more. > Disks amrd0 > KB/t 85.39 > tps 5 > MB/s 0.38 > % busy 99 > Apart of all, I tried to make mutex profiling and here's the results > (sorted by the total number of acquisitions): > > Bad case: > > 102 223514 273977 0 14689 1651568 /usr/src/sys/vm/uma_core.c:2349 (512) > 950 263099 273968 0 15004 14427 /usr/src/sys/vm/uma_core.c:2450 (512) > 108 150422 175840 0 10978 22988519 /usr/src/sys/vm/uma_core.c:1888 (mbuf) > Here you can see that high UMA activity happens in periods of low disk > performance. But I'm not sure whether this is a root of the problem, not > a consequence. The extremely high contention there does seem to say you have a mbuf starvation problem and not a disk problem. I don't know why this would be happening off-hand. Can you also provide more details about the system hardware and configuration? Kris
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?47140906.2020107>