On Thu, Nov 10 2005, Tejun Heo wrote:
Unlike other ioscheds, as-iosched handles alias by chaing them using
rq->queuelist. As aliased requests are very rare in the first place,
this complicates merge/dispatch handling without meaningful
performance improvement. This patch updates as-iosched to dump
aliased requests into dispatch queue as other ioscheds do.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
In theory the way 'as' handles the aliases is faster since we postpone
pushing them to the dispatch list at the same point (and they have
strong (if not identical) locality). But it is much simpler to just
shove the offending requests onto the dispatch list.
It's really up to Nick - what do you think? Leaving patch below.
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Jens, I've tested this change for several hours, but it might be
better to postpone this change to next release. It's your call.