From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 1/9] move blk_iopoll to limit and make it generally available Date: Sat, 14 Nov 2015 08:02:00 +0100 Message-ID: <20151114070200.GA27738@lst.de> References: <1447422410-20891-1-git-send-email-hch@lst.de> <1447422410-20891-2-git-send-email-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Or Gerlitz Cc: Sagi Grimberg , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Bart Van Assche , axboe-b10kYP2dOMg@public.gmane.org, "linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linux Kernel List-Id: linux-rdma@vger.kernel.org On Fri, Nov 13, 2015 at 05:23:39PM +0200, Or Gerlitz wrote: > On Fri, Nov 13, 2015 at 3:46 PM, Christoph Hellwig wrote: > > The new name is irq_poll as iopoll is already taken. Better suggestions > > welcome. > > Sagi (or Christoph if you can address that), > > @ some pointer over the last 18 months there was a port done at > mellanox for iser to use blk-iopoll and AFAIR it didn't work well or > didn't work at all. Can you tell now what was the problem and how did > you address it at your generalization? Hi Or, Sagi mentioned last time he tried a similar approach in iSER he saw some large latency sparks. We've seen nothing worse than the original approach. The Flash memory summit slide set has some numbers: http://www.flashmemorysummit.com/English/Collaterals/Proceedings/2015/20150811_FA11_Bandic.pdf they aren't quite up to date, but the latency distribution hasn't really changed. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751095AbbKNHCF (ORCPT ); Sat, 14 Nov 2015 02:02:05 -0500 Received: from verein.lst.de ([213.95.11.211]:45177 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750899AbbKNHCD (ORCPT ); Sat, 14 Nov 2015 02:02:03 -0500 Date: Sat, 14 Nov 2015 08:02:00 +0100 From: Christoph Hellwig To: Or Gerlitz Cc: Sagi Grimberg , "linux-rdma@vger.kernel.org" , Bart Van Assche , axboe@fb.com, "linux-scsi@vger.kernel.org" , Linux Kernel Subject: Re: [PATCH 1/9] move blk_iopoll to limit and make it generally available Message-ID: <20151114070200.GA27738@lst.de> References: <1447422410-20891-1-git-send-email-hch@lst.de> <1447422410-20891-2-git-send-email-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 13, 2015 at 05:23:39PM +0200, Or Gerlitz wrote: > On Fri, Nov 13, 2015 at 3:46 PM, Christoph Hellwig wrote: > > The new name is irq_poll as iopoll is already taken. Better suggestions > > welcome. > > Sagi (or Christoph if you can address that), > > @ some pointer over the last 18 months there was a port done at > mellanox for iser to use blk-iopoll and AFAIR it didn't work well or > didn't work at all. Can you tell now what was the problem and how did > you address it at your generalization? Hi Or, Sagi mentioned last time he tried a similar approach in iSER he saw some large latency sparks. We've seen nothing worse than the original approach. The Flash memory summit slide set has some numbers: http://www.flashmemorysummit.com/English/Collaterals/Proceedings/2015/20150811_FA11_Bandic.pdf they aren't quite up to date, but the latency distribution hasn't really changed.