On Fri, 16 Jan 2009 07:48:18 +0100 Jens Axboe <jens.axboe@xxxxxxxxxx> wrote: > > For non-queuing devices, I think our current check is a bit too drastic. > We probably want to change that to > > int dont_plug(q) > { > return blk_queue_nonrot(q) && blk_queue_tagged(q); > } > Please do. The MMC block driver sets nonrot as of late, but it is extremely dependent on merging. The command overhead is just silly, so to get anywhere near the speed numbers indicated in marketing you need large requests. It seems that too many confuse "non-rotational" with "low latency", which isn't always the same. :) Rgds -- -- Pierre Ossman Linux kernel, MMC maintainer http://www.kernel.org rdesktop, core developer http://www.rdesktop.org WARNING: This correspondence is being monitored by the Swedish government. Make sure your server uses encryption for SMTP traffic and consider using PGP for end-to-end encryption.
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