On Thu, 1 Sep 2005, Nick Piggin wrote:

Holger Kiehl wrote:

quoted

meminfo.dump:

   MemTotal:      8124172 kB
   MemFree:         23564 kB
   Buffers:       7825944 kB
   Cached:          19216 kB
   SwapCached:          0 kB
   Active:          25708 kB
   Inactive:      7835548 kB
   HighTotal:           0 kB
   HighFree:            0 kB
   LowTotal:      8124172 kB
   LowFree:         23564 kB
   SwapTotal:    15631160 kB
   SwapFree:     15631160 kB
   Dirty:         3145604 kB

Hmm OK, dirty memory is pinned pretty much exactly on dirty_ratio
so maybe I've just led you on a goose chase.

You could
   echo 5 > /proc/sys/vm/dirty_background_ratio
   echo 10 > /proc/sys/vm/dirty_ratio

To further reduce dirty memory in the system, however this is
a long shot, so please continue your interaction with the
other people in the thread first.

Yes, this does make a difference, here the results of running

   dd if=/dev/full of=/dev/sd?1 bs=4M count=4883

on 8 disks at the same time:

   34.273340
   33.938829
   33.598469
   32.970575
   32.841351
   32.723988
   31.559880
   29.778112

That's 32.710568 MB/s on average per disk with your change and without
it it was 24.958557 MB/s on average per disk.

I will do more tests tomorrow.

Thanks,
Holger