Re: [PATCH] block/elevator updates + deadline i/o scheduler

From: Jens Axboe (axboe@suse.de)
Date: Tue Jul 30 2002 - 02:57:38 EST


Hi,

An updated version of the deadline i/o scheduler against 2.5.29 is now
available. Changes since last version:

features:

o 'fifo_batch' meant "move this number of entries to dispatch queue" in
the previous version, now it means "move entries to dispatch queue at
this max cost". It is complimented by 'seek_cost' which is a simple
measure of transfer-time vs seek-time cost. If a request X+1 is
contigous to request X, then it is accounted at cost '1'. If not, it's
accounted at cost 'seek_cost'.

o Doing numbers on q->last_merge hits in the linus elevator showed
impressive amount of hits even when lots of threads where banging the
queue at the same time. So add q->last_merge hints to this scheduler
too.

fixes:

o remember to actually register e->merge_cleanup so the merge cleanup
parts works. This caused us to miss out on a number of back merges.

o use wli's hash_long() as the merge hash. gets good distribution on
various benchmark runs and is fast, very nice :-)

o various cleanups

So no serious bug found (ie crashes or data corruption issues). Again,
mainly tested on SCSI, briefly tested on IDE as well. Due to better
design of the i/o scheduler interface in 2.5 in general, integrity
testing on IDE isn't nearly as important as it was in 2.4 for instance.
So I consider the patch stable for general use right now.

elv-queue_head-misc-2
        various block- and i/o scheduler interface updates. needs to be
        applied first.

deadline-iosched-7
        the deadline i/o scheduler.

Find them on kernel.org as well of course. Testing welcome!

-- 
Jens Axboe



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