Messages in this thread | | | Date | Sat, 17 Apr 2004 16:30:37 -0700 | From | Marc Singer <> | Subject | Re: vmscan.c heuristic adjustment for smaller systems |
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On Sat, Apr 17, 2004 at 04:21:25PM -0700, Andrew Morton wrote: > Marc Singer <elf@buici.com> wrote: > > > > I'd say that there is no statistically significant difference between > > these sets of times. However, after I've run the test program, I run > > the command "ls -l /proc" > > > > swappiness > > 60 (default) 0 > > ------------ -------- > > elapsed time(s) 18 1 > > 30 1 > > 33 1 > > How on earth can it take half a minute to list /proc?
I've watched the vmscan code at work. The memory pressure is so high that it reclaims mapped pages zealously. The program's code pages are being evicted frequently.
I would like to show a video of the ls -l /proc command. It's remarkable. The program pauses after displaying each line.
> > This is the problem. Once RAM fills with IO buffers, the kernel's > > tendency to evict mapped pages ruins interactive performance. > > Is everything here on NFS, or are local filesystemms involved? (What does > "mount" say?)
# mount rootfs on / type rootfs (rw) /dev/root on / type nfs (rw,v2,rsize=4096,wsize=4096,hard,udp,nolock,addr=192.168.8.1) proc on /proc type proc (rw) devpts on /dev/pts type devpts (rw)
I've been wondering if the swappiness isn't a red herring. Is it reasonable that the distress value (in refill_inactive_zones ()) be 50?
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