Messages in this thread | | | Date | Fri, 5 Feb 2010 14:12:21 +0100 | From | Jens Axboe <> | Subject | Re: kswapd continuously active |
| |
On Fri, Feb 05 2010, Jan Engelhardt wrote: > > On Friday 2010-02-05 14:00, Jens Axboe wrote: > >> >January 25 Feb-05 > >> >MemTotal: 8166752 kB 8166752 > >> >MemFree: 3243552 kB 3781776 > >> >Buffers: 207968 kB 4912 > >> >Cached: 2728216 kB 2684400 > >> >SwapCached: 0 kB 0 > >> >Active: 2203136 kB 495624 > >> >Inactive: 2152544 kB 3263136 > >> >Active(anon): 1167256 kB 488168 > >> >Inactive(anon): 252952 kB 583912 > >> >Active(file): 1035880 kB 7456 > >> >Inactive(file): 1899592 kB 2679224 > >> >Unevictable: 0 kB 0 > >> >Mlocked: 0 kB 0 > >> >SwapTotal: 0 kB 0 > >> >SwapFree: 0 kB 0 > >> >Dirty: 141624 kB 2662184 > >> >Writeback: 0 kB .. > >> > >> Today this happened again. So I looked at /proc/meminfo to paste today's > >> values next to those from January. That is when I noticed the "Dirty" > >> value - and thus I ran > >> > >> watch -d -n 1 'grep Dirty /proc/meminfo' > >> > >> What I see is that the dirty amount - a sync is currently running - > >> only decreases with at most 400 KB/sec, often less than that. > > > >I'm guessing the barriers and commits are what is killing your > >performance. What happens with barrier=0? > > The ext4 filesystem is already mounted with barrier=0. If there > is any block-level barriers I also can turn off, what would be > the command?
barrier=0 is enough. I do wonder why your writeback rate is that slow, then. The disk has write back caching enabled?
-- Jens Axboe
| |