Messages in this thread | | | Subject | Re: [PATCH] O11int for interactivity | From | Martin Josefsson <> | Date | 05 Aug 2003 19:00:09 +0200 |
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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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