From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [RFT] major libata update Date: Tue, 16 May 2006 21:14:48 -0400 Message-ID: <446A7908.308@garzik.org> References: <20060515170006.GA29555@havoc.gtf.org> <4469B93E.6010201@emc.com> <4469E0DB.1040709@garzik.org> <4469EEC0.4060907@gmail.com> <446A1A21.80501@emc.com> <446A63F6.5030706@gmail.com> <446A6615.6050701@garzik.org> <446A678E.8030403@garzik.org> <446A6ECD.7080104@garzik.org> <446A734A.6020504@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:34461 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S932402AbWEQBOv (ORCPT ); Tue, 16 May 2006 21:14:51 -0400 In-Reply-To: <446A734A.6020504@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: ric@emc.com, linux-ide@vger.kernel.org, Mark Lord , Jens Axboe Tejun Heo wrote: > Jeff Garzik wrote: >> As another side note, command coalescing is worth experimenting with. > > Might be, but I'm a bit skeptical. We might lose more to added latency. Yes, that's the biggest item of note. Still, it would be worth turning on if interrupts exceed a certain threshold, such as 1000/second. Each interrupt handler setup and call, even with PCI MSI, has a certain fixed amount overhead. Command coalescing can mitigate that overhead. Jeff