From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [RFC] hpsa: work in progress "lockless monster" patches Date: Sun, 27 Jul 2014 17:24:46 +0200 Message-ID: <53D519BE.9000204@suse.de> References: <20140725192859.GU14599@beardog.cce.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:37166 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751745AbaG0PYv (ORCPT ); Sun, 27 Jul 2014 11:24:51 -0400 In-Reply-To: <20140725192859.GU14599@beardog.cce.hp.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: scameron@beardog.cce.hp.com, linux-scsi@vger.kernel.org Cc: jbottomley@parallels.com, martin.petersen@oracle.com, thenzl@redhat.com, hch@infradead.org, bvanassche@acm.org, axboe@kernel.dk, elliott@hp.com, scott.teel@hp.com, webbnh@hp.com, joseph.t.handzik@hp.com, justin.lindley@hp.com On 07/25/2014 09:28 PM, scameron@beardog.cce.hp.com wrote: > > hpsa: Work In Progress: "lockless monster" patches > > To be clear, I am not suggesting that these patches be merged at this= time. > > This patchset is vs. Christoph Hellwig's scsi-mq.4 branch which > may be found here: git://git.infradead.org/users/hch/scsi.git > > We've been working for a long time on a patchset for hpsa to remove > all the locks from the main i/o path in pursuit of high IOPS. Some > of that work is already upstream, but a lot more of it is not quite > yet ready to be merged. However, I think we've "gone dark" for a bit > too long on this, and even though the patches aren't really ready to > be merged just yet, I thought I should let other people who might be > interested have a look anyway, as things are starting to be at least > more stable than unstable. Be warned though, there are still some > problems, esp. around error recovery. > > That being said, with the right hardware (fast SAS SSDs, recent Smart > Arrays e.g. P430, with up-to-date firmware, attached to recent disk e= nclosures) > with these patches and the scsi-mq patches, it is possible to get aro= und > ~970k IOPS from a single logical drive on a single controller. > > There are about 150 patches in this set. Rather than bomb the list > with that, here is a link to a tarball of the patches in the form of > an stgit patch series: > > https://github.com/smcameron/hpsa-lockless-patches-work-in-progress/b= lob/master/hpsa-lockless-vs-hch-scsi-mq.4-2014-07-25-1415CDT.tar.bz2?ra= w=3Dtrue > > In some cases, I have probably erred on the side of having too many t= oo > small patches, on the theory that it is easier to bake a cake than to > unbake a cake. Before these are submitted "for reals", there will be > some squashing of patches, along with other cleaning up. > > There are some patches in this set which are already upstream in > James's tree which do not happen to be in Christoph's tree > (most of which are named "*_sent_to_james"). There are also > quite a few patches which are strictly for debugging and are not > ever intended to be merged. > Hmm. While you're about to engage on a massive rewrite _and_ we're=20 having 64bit LUN support now, what about getting rid of the weird=20 internal LUN mapping? That way you would get rid of this LUN rescan=20 thingie and the driver would look more sane. Plus the REPORT LUN command would actually return the correct data ... Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html