Messages in this thread | | | Date | Tue, 14 Oct 2008 09:54:08 +0200 | From | Jens Axboe <> | Subject | Re: QUEUE_FLAG_NONROT and merges |
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On Tue, Oct 14 2008, Pierre Ossman wrote: > Hi Jeff, > > I noticed you've added a new flag to indicate that the drive has no > seek costs and I figured it would be a good idea to use that on the > MMC/SD cards.
That was me, actually...
> Since the name isn't entirely clear in what is implied, I just wanted > to check that there are no plans to assume that there is negligable > request overhead for queues with this flag. I.e. the flag should > indicate that the elevator doesn't have to care about seeks, but it > should still try to merge requests to reduce the transaction overhead.
Sounds about right. The flag is just meant to indicate zero-seek cost, as devices will still have per-command overheads, merging is still applicable.
So yes, you want to set that flag for mmc/sd cards, definitely.
-- Jens Axboe
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