Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757006AbZDWLSk (ORCPT ); Thu, 23 Apr 2009 07:18:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756159AbZDWLSa (ORCPT ); Thu, 23 Apr 2009 07:18:30 -0400 Received: from fg-out-1718.google.com ([72.14.220.156]:31199 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755788AbZDWLS2 (ORCPT ); Thu, 23 Apr 2009 07:18:28 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=CvcQh/oE3tFO29XzBfdD8L8aXIYYOhhZd/hP2NmPNHiilgi+nAwI1aKz5npeJJR81Z EnTKMxUjpxEz73Rh2/CiXj9KRc//vo4I123CcI5RZqsWikG43e7lwIAFHRPV2iekxuMr Wun9o6aF77R69TTYmsmEIKPDL2pvHm69zCd2A= MIME-Version: 1.0 In-Reply-To: <4e5e476b0904221407v7f43c058l8fc61198a2e4bb6e@mail.gmail.com> References: <4e5e476b0904221407v7f43c058l8fc61198a2e4bb6e@mail.gmail.com> Date: Thu, 23 Apr 2009 11:18:27 +0000 Message-ID: <4d8e3fd30904230418g20e89cb1se4303754914bbcd7@mail.gmail.com> Subject: Re: Reduce latencies for syncronous writes and high I/O priority requests in deadline IO scheduler From: Paolo Ciarrocchi To: Corrado Zoccolo Cc: jens.axboe@oracle.com, Linux-Kernel Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1116 Lines: 30 On 4/22/09, Corrado Zoccolo wrote: > Hi, > deadline I/O scheduler currently classifies all I/O requests in only 2 > classes, reads (always considered high priority) and writes (always > lower). > The attached patch, intended to reduce latencies for syncronous writes > and high I/O priority requests, introduces more levels of priorities: > * real time reads: highest priority and shortest deadline, can starve > other levels > * syncronous operations (either best effort reads or RT/BE writes), > mid priority, starvation for lower level is prevented as usual > * asyncronous operations (async writes and all IDLE class requests), > lowest priority and longest deadline > numbers are impressive. do you observe better latencies in normal desktop usage as well? ciao, -- Paolo http://paolo.ciarrocchi.googlepages.com/ http://mypage.vodafone.it/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/