Date: Thu, 20 Jan 2005 02:36:30 +0100 From: Bartosz Fabianowski <freebsd@chillt.de> To: freebsd-stable@freebsd.org Subject: Persisting troubles with periodic stalls every few minutes Message-ID: <41EF0B1E.6010209@chillt.de>
next in thread | raw e-mail | index | archive | help
Hi list, I have been having a lot of trouble with performance on my laptop, which I first set up with 5.3-RELEASE and constantly keep up to date with 5.3-STABLE. The box runs stable, but periodically, somewhere between every few minutes down to every few seconds, it stalls for 5 seconds. By that I mean that the screen is not being refreshed and all keyboard strokes go into some kind of buffer to get processed when the stall is over. Some key strokes also get lost or reversed in order, which makes this even more annoying. I know that during the stalls, CPU usage goes up to 100%, so it is some process that periodically wakes up and hogs the CPU for a few seconds. Also, during the stalls, there is always a lot of disk activity. The only "special" thing about this machine is that /usr/home is GBDE encrypted. But even when I am not doing anything on that partition, stalls occur. The rate of stalls varies a depending on what I am doing. Even when the box is idle, it does stall periodically. But when I am making world, the box becomes almost completely unusable as disk activity on /usr (which is not GBDE encrypted) triggers the same symptoms. The trouble is that I cannot figure out how to find the responsible process. Tools such as top(1) update in one second intervals at best and as there are no screen updates during the stall, so they produce nothing useful. The only tool that gave me some kind of information was systat(1). When I invoke "systat -vmstat 1", I see the following: When everything is working normally, the CPU is at: 15% system 30% user 65% idle At the first screen update after a stall, the CPU is at: 15% system 85% user 0% idle Also, the VM statistics such as "zfod" and "ofod" have jumped from their usual zero level to several thousand. And disk activity is reported as high, of course. A couple seconds after the stall is over, all statistics return to their normal values. So, some user process is misbehaving. And has been doing so ever since this box was set up. Plus, it is somehow disk related and happens no matter what I am running or not, what I am doing or not. Any ideas on how to debug this? How can I find the guilty process? Thanks for any and all input, - Bartosz Fabianowski PS: According to sysctl, DMA is enabled on both ata and atapi so that is not the issue.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?41EF0B1E.6010209>