On 01/31/2017 11:02 AM, Christoph Hellwig wrote: > On Tue, Jan 31, 2017 at 10:25:50AM +0100, Hannes Reinecke wrote: >> Hi all, >> >> this is a patchset to enable full multiqueue support for the mpt3sas driver. >> While the HBA only has a single mailbox register for submitting commands, >> it does have individual receive queues per MSI-X interrupt and as such >> does benefit from converting it to full multiqueue support. > > Explanation and numbers on why this would be beneficial, please. > We should not need multiple submissions queues for a single register > to benefit from multiple completion queues. > Well, the actual throughput very strongly depends on the blk-mq-sched patches from Jens. As this is barely finished I didn't post any numbers yet. However: With multiqueue support: 4k seq read : io=60573MB, bw=1009.2MB/s, iops=258353, runt= 60021msec With scsi-mq on 1 queue: 4k seq read : io=17369MB, bw=296291KB/s, iops=74072, runt= 60028msec So yes, there _is_ a benefit. (Which is actually quite cool, as these tests were done on a SAS3 HBA, so we're getting close to the theoretical maximum of 1.2GB/s). (Unlike the single-queue case :-) Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
