On Tue, 2003-08-05 at 07:55, Andrew Morton wrote:
> Another possibility is that xmms is getting stuck in a read. The
> anticipatory scheduler is currently rather tuned for throughput. Judging
> by the vmstat trace which was posted, we have a classic
> read-stream-vs-write-stream going on. We trade off latency versus
> throughput; perhaps wrongly. You can decrease latency (at the expense of
> throughput) by decreasing the settings in /sys/block/hda/queue/iosched.
>
> To a point, it is a nice linear tradeoff, and someone should put the time
> in to tweak and characterise it.
I believe it was my trace wli posted.
No swapping was going on, swappiness set to 30
X was quite jerky and uninteractive during this and sometimes it froze
for up to 5 seconds (the sound usually stopped during the freezing).
Since there wasn't any swapping going on and quite a lot of cpu left we
either have quite some latency when reading back parts of X that
previously got discarded or massive stalls in kernelspace somewhere.
One thing I noticed was that when evolution started checking for new
mail in a lot of folders I get a lot of seeks and the throughput
naturally decreased but X got really responsive again. This points away
from X beeing discarded and read back in from disk since that would take
some time with all those seeks as well.
The machine this was tested on is a pIII 700 with 704MB ram and IDE
disks (everything was against the same disk)
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This archive was generated by hypermail 2b29 : Thu Aug 07 2003 - 22:00:29 EST