From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: SSD slowdown with 3.3.X? Date: Fri, 20 Apr 2012 22:43:27 -0400 Message-ID: <4F921ECF.2080303@teksavvy.com> References: <4F8F7533.6020300@gmail.com> <4F8F82EC.1060708@teksavvy.com> <4F90C4CF.1010000@gmail.com> <4F921E18.6000301@teksavvy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from ironport-out.teksavvy.com ([206.248.143.162]:42719 "EHLO ironport-out.teksavvy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753588Ab2DUCn2 (ORCPT ); Fri, 20 Apr 2012 22:43:28 -0400 In-Reply-To: <4F921E18.6000301@teksavvy.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Joe Ceklosky Cc: "linux-ide@vger.kernel.org >> IDE/ATA development list" On 12-04-20 10:40 PM, Mark Lord wrote: > On 12-04-19 10:07 PM, Joe Ceklosky wrote: >> Mark, >> >> >> Thanks for the info, but nothing like that shows up: >> >> >> [jceklosk@neptune tmp]$ cat c-3.2.15 >> noop deadline [cfq] >> noop deadline [cfq] >> >> >> [jceklosk@neptune tmp]$ cat c-3.3.2 >> noop deadline [cfq] >> noop deadline [cfq] > > > Well, the stuff you posted (above) shows that cfq is being used > instead of noop. For SSDs, noop is the more natural choice, > and used to be the default in the kernel for a while. > I wonder when that changed? Looking into the block layer now, I see that "cfq" at some point became "SSD aware", which is probably when the default io scheduler for SSDs changed back to cfq from noop. Not 100% sure, but that's how it appears now. I still have my systems set it to noop when an SSD is detected.