From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Moyer Subject: Re: New driver mtipx2xx submission Date: Tue, 28 Jun 2011 11:38:01 -0400 Message-ID: References: <22A973199D2C2F46933448F6E7990A300204F2BC@ntxboimbx31.micron.com> <20110428230605.78c55c70@lxorguk.ukuu.org.uk> <22A973199D2C2F46933448F6E7990A300204F728@ntxboimbx31.micron.com> <20110502184206.25907c5e@lxorguk.ukuu.org.uk> <22A973199D2C2F46933448F6E7990A300214B0D6@ntxboimbx31.micron.com> <20110511202013.075b07cc@lxorguk.ukuu.org.uk> <4DD722DB.8030303@micron.com> <22A973199D2C2F46933448F6E7990A300239EA77@ntxboimbx31.micron.com> <20110601212129.11534c55@lxorguk.ukuu.org.uk> <4DF80ADE.8020206@micron.com> <22A973199D2C2F46933448F6E7990A3002697E77@ntxboimbx31.micron.com> <20110628163125.0f2acc94@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:23448 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756644Ab1F1PiO (ORCPT ); Tue, 28 Jun 2011 11:38:14 -0400 In-Reply-To: <20110628163125.0f2acc94@lxorguk.ukuu.org.uk> (Alan Cox's message of "Tue, 28 Jun 2011 16:31:25 +0100") Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: "Asai Thambi Samymuthu Pattrayasamy (asamymuthupa) [CONTRACTOR]" , linux-ide@vger.kernel.org Alan Cox writes: >> Anywho, a 40% difference is pretty significant (though NUMA can have >> that sort of impact). Alan, what do you think? I was never clear on >> how exactly the ahci driver would handle a queue depth larger than 32 >> (if it can't, then clearly we'd need a block driver for this hardware). > > The AHCI driver can drop that support in fairly easily all the queue > handling is nicely pluggable. > > A 40% improvement is a big win, but it seems to me that if any of that is > not hardware related (ie the bigger command queue) then we need to be > fixing the existing driver to improve *ALL* AHCI devices. Or are we going > to end up with a pile of AHCIish drivers for every random device on the > planet ? The 40% number was for a queue depth of 32, so yes, there's room for improvement in AHCI (so long as it isn't related to the block layer's rq_affinity interacting poorly with NUMA or some such thing). > My request for info on the Micron errata has so far been ignored, > questions on what is involved in the queue stuff likewise. I'd like to > see those matters resolved. Asai? -Jeff