From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Stephen Bates" Subject: Re: [LSF/MM TOPIC][LSF/MM ATTEND] NAPI polling for block drivers Date: Wed, 11 Jan 2017 22:36:51 -0600 Message-ID: <43b3038b57ed5c00a73ebc5457d048d5.squirrel@webmail.raithlin.com> References: <20170111134312.GH6286@linux-x5ow.site> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: In-Reply-To: Sender: linux-block-owner@vger.kernel.org To: Jens Axboe Cc: Johannes Thumshirn , "lsf-pc@lists.linux-foundation.org" , Christoph Hellwig , Sagi Grimberg , linux-scsi@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Keith Busch List-Id: linux-scsi@vger.kernel.org >> >> I'd like to attend LSF/MM and would like to discuss polling for block >> drivers. >> >> Currently there is blk-iopoll but it is neither as widely used as NAPI >> in the networking field and accoring to Sagi's findings in [1] >> performance with polling is not on par with IRQ usage. >> >> On LSF/MM I'd like to whether it is desirable to have NAPI like polling >> in more block drivers and how to overcome the currently seen performance >> issues. > > It would be an interesting topic to discuss, as it is a shame that > blk-iopoll isn't used more widely. > > -- > Jens Axboe > I'd also be interested in this topic. Given that iopoll only really makes sense for low-latency, low queue depth environments (i.e. down below 10-20us) I'd like to discuss which drivers we think will need/want to be upgraded (aside from NVMe ;-)). I'd also be interested in discussing how best to enable and disable polling. In the past some of us have pushed for a "big hammer" to turn polling on for a given device or HW queue [1]. I'd like to discuss this again as well as looking at other methods above and beyond the preadv2 system call and the HIPRI flag. Stephen [1] http://marc.info/?l=linux-block&m=146307410101827&w=2 > _______________________________________________ > Linux-nvme mailing list > Linux-nvme@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-nvme > >