From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matias Bjorling Subject: Re: blk-mq, scsi-mq, UFS Date: Sat, 27 Sep 2014 19:42:42 +0200 Message-ID: <5426F712.3010501@bjorling.me> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-la0-f43.google.com ([209.85.215.43]:48691 "EHLO mail-la0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751985AbaI0Rmq (ORCPT ); Sat, 27 Sep 2014 13:42:46 -0400 Received: by mail-la0-f43.google.com with SMTP id gb8so6525530lab.16 for ; Sat, 27 Sep 2014 10:42:44 -0700 (PDT) In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Andras Kovacs , linux-scsi@vger.kernel.org On 09/27/2014 12:14 AM, Andras Kovacs wrote: > Hi all, > > could someone explain to me: > > - what is the difference between blk-mq and scsi-mq blk-mq is the actual block layer, while scsi-mq enables the scsi subsystem to use blk-mq. Any driver that wish to use blk-mq, has to explicit hook into it. > - why don't I observe large speedups when running the same tiotests on Linux > v3.12 (which has no blk-mq) and Linux v3.14 (which does have blk-mq) on a > Xilinx Zynq development board (the two Linux versions are configured by > Xilinx Zynq and I know only how to add kernel command line parameters)? Only the virtio driver (and the null blk driver) have been converted to blk-mq in 3.14. > - when Linux v3.17 becomes available (and Xilinx Zynq ports it for their > development board) will I see large speedups reading/writing to the target > SDD (which is driven through the UFS driver)? Depends if you're CPU bound. If you are, then a speedup is expected. You will at least see lower CPU usage. scsi-mq has to be explicit enabled with the scsi_mod.use_blk_mq=Y in the kernel boot options for 3.17 until it is marked stable. > > Any and all info would be greatly appreciated. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >