From mboxrd@z Thu Jan 1 00:00:00 1970 From: Artem Bityutskiy Subject: Re: [PATCH 2/2] UBIFS: start using hrtimers Date: Fri, 29 May 2009 17:00:18 +0300 Message-ID: <4A1FEA72.80109@nokia.com> References: <20090529150929.8912.33879.sendpatchset@localhost.localdomain> <20090529150944.8912.95076.sendpatchset@localhost.localdomain> <1243603957.23657.217.camel@twins> Reply-To: Artem.Bityutskiy@nokia.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Artem Bityutskiy , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , linux-fsdevel@vger.kernel.org, Steven Rostedt , Arjan van de Ven To: Peter Zijlstra Return-path: Received: from smtp.nokia.com ([192.100.105.134]:62913 "EHLO mgw-mx09.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755523AbZE2OCF (ORCPT ); Fri, 29 May 2009 10:02:05 -0400 In-Reply-To: <1243603957.23657.217.camel@twins> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Peter Zijlstra wrote: > On Fri, 2009-05-29 at 18:09 +0300, Artem Bityutskiy wrote: >> From: Artem Bityutskiy >> Subject: [PATCH 2/2] UBIFS: start using hrtimers >> >> UBIFS uses timers for write-buffer write-back. It is not >> crucial for us to write-back exactly on time. We are fine >> to write-back a little earlier or later. And this means >> we may optimize UBIFS timer so that it could be groped >> with a close timer event, so that the CPU would not be >> waken up just to do the write back. This is optimization >> to lessen power consumption, which is important in >> embedded devices UBIFS is used for. >> >> hrtimers have a nice feature: they are effectively range >> timers, and we may defind the soft and hard limits for >> it. Standard timers do not have these feature. They may >> only be made deferrable, but this means there is effectively >> no hard limit. So, we will better use hrtimers. >> >> Signed-off-by: Artem Bityutskiy >> --- >=20 > Seems sane enough from a hrtimer POV, but isn't this already > functionality that the VFS/pdflush provide? And I also have a longer term plan to switch the VFS/pdflush timer to be a range hrtimer, BTW, just like you suggested me once. --=20 Best Regards, Artem Bityutskiy (=D0=90=D1=80=D1=82=D1=91=D0=BC =D0=91=D0=B8=D1=82=D1=8E= =D1=86=D0=BA=D0=B8=D0=B9) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html