Re: Ideas for a new io scheduler for desktop

From: Prakash K. Cheemplavam
Date: Wed Nov 10 2004 - 06:23:22 EST

Robert Love wrote:
On Wed, 2004-11-10 at 02:32 +0100, Pedro Larroy wrote:

I think that a new io-scheduler that gave priority to bursty access to
block devices would be interesting for desktop and workstation use, and
even for some servers.

I'm often waiting for graphical aplications, vim, mutt, and almost every
program to which I have to interact with because they are blocked
waiting for just a few blocks of IO that won't get served fast just
because there's a single process hog that's provoking that high latency.


What you are seeing is the affect of read requests being synchronous,
and thus the pain of read latency, and write requests to one part of the
disk starving other requests.

Have you tried the new 2.6 I/O schedulers? They should prevent this

If you are using 2.6, then your problem might not lie with the I/O
scheduler. Read request deadlines are very low in both the deadline and
anticipatory I/O scheduler.

BTW, I saw the same problem, though not with reading, but with writing to disk. See thread (well nobody answered to it yet):

[2.6.10-rc1 and prev] System unuseable while writing to disk

It really takes away the fun... :(


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