Commit 6ce3dd6e authored by Committed by Jens AxboeBrowse files
blk-mq: issue directly if hw queue isn't busy in case of 'none'
In case of 'none' io scheduler, when hw queue isn't busy, it isn't necessary to enqueue request to sw queue and dequeue it from sw queue because request may be submitted to hw queue asap without extra cost, meantime there shouldn't be much request in sw queue, and we don't need to worry about effect on IO merge. There are still some single hw queue SCSI HBAs(HPSA, megaraid_sas, ...) which may connect high performance devices, so 'none' is often required for obtaining good performance. This patch improves IOPS and decreases CPU unilization on megaraid_sas, per Kashyap's test. Cc: Kashyap Desai <email@example.com> Cc: Laurence Oberman <firstname.lastname@example.org> Cc: Omar Sandoval <email@example.com> Cc: Christoph Hellwig <firstname.lastname@example.org> Cc: Bart Van Assche <email@example.com> Cc: Hannes Reinecke <firstname.lastname@example.org> Reported-by: Kashyap Desai <email@example.com> Tested-by: Kashyap Desai <firstname.lastname@example.org> Signed-off-by: Ming L...