Subject: Re: performance slowdown after longish uptime
To: Mark Davies <mark@MCS.VUW.AC.NZ>
From: Richard Earnshaw <email@example.com>
Date: 08/25/2000 10:22:13
> We have a problem using current that after a machine has been running for 1 to
> 2 weeks it gets into a state where performance goes to pot with large amounts
> of disk activity accompanying any operation.
> eg starting netscape takes over a minute rather than the normal 15 seconds or
> so. This persists until you reboot the machine.
> This is with 1.5A on i386 but the problem has been there with any current
> version we've run back through 1.4P and possibly earlier. I had been
> assuming that it was somehow softdep related so upgraded to a new current each
> time significant bugfixes to the softdep code were announced, then waited a
> couple of weeks to see if the problem was still there. Thinking about it I'm
> not sure how it could be softdep related as it happens when all you are doing
> is reading from a filesystem that is not mounted with softdep.
> So can anyone suggest what I can do to try and pin this down?
Well I saw a problem like this a while back (it started about the time
that softdep was integrated). The symptoms were similar to those you
describe -- heavy disk activity after the machine had been up for about a
But that problem was fixed somewhere around 1.4X by Chuck based on my PR.
See kern/9792 for details.