Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753935AbWLRMjl (ORCPT ); Mon, 18 Dec 2006 07:39:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753936AbWLRMjk (ORCPT ); Mon, 18 Dec 2006 07:39:40 -0500 Received: from wx-out-0506.google.com ([66.249.82.228]:61889 "EHLO wx-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753935AbWLRMjk (ORCPT ); Mon, 18 Dec 2006 07:39:40 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=X1/d6YTB42Rd3iZiYVM50P+AM38qIDrcicx3yO3dI/EpQC4UOaiti8gGRPVe6oaRx+VH0RzjXR28TIDVpc3AA/b17WzrZWm1R45tSPCzi1peH3CQzfmlkhA7txwingOoK8NLVOXmW/pycQrEzkxGVlp+LUtx9+gktD0LwPsRgf8= Message-ID: <652016d30612180439y6cd12089l115e4ef6ce2e59fe@mail.gmail.com> Date: Mon, 18 Dec 2006 18:24:39 +0545 From: "Manish Regmi" To: "Arjan van de Ven" Subject: Re: Linux disk performance. Cc: linux-kernel@vger.kernel.org, kernelnewbies@nl.linux.org In-Reply-To: <1166431020.3365.931.camel@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <652016d30612172007m58d7a828q378863121ebdc535@mail.gmail.com> <1166431020.3365.931.camel@laptopd505.fenrus.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1196 Lines: 31 On 12/18/06, Arjan van de Ven wrote: > if you want truely really smooth writes you'll have to work for it, > since "bumpy" writes tend to be better for performance so naturally the > kernel will favor those. > > to get smooth writes you'll need to do a threaded setup where you do an > msync/fdatasync/sync_file_range on a frequent-but-regular interval from > a thread. Be aware that this is quite likely to give you lower maximum > performance than the batching behavior though. > Thanks... But isn't O_DIRECT supposed to bypass buffering in Kernel? Doesn't it directly write to disk? I tried to put fdatasync() at regular intervals but there was no visible effect. -- --------------------------------------------------------------- regards Manish Regmi --------------------------------------------------------------- UNIX without a C Compiler is like eating Spaghetti with your mouth sewn shut. It just doesn't make sense. - 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/