From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Parag Warudkar" Subject: Re: init_timer_deferrable conversion Date: Mon, 17 Dec 2007 12:47:59 -0500 Message-ID: <82e4877d0712170947v45929acv92e0d34c86d82c6d@mail.gmail.com> References: <20071217095504.b02241ee.dada1@cosmosbay.com> <20071217152943.10470215.dada1@cosmosbay.com> <20071217090000.64499fba@deepthought> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Eric Dumazet" , linux-kernel@vger.kernel.org, "David Miller" , "netdev@vger.kernel.org" To: "Stephen Hemminger" Return-path: Received: from el-out-1112.google.com ([209.85.162.181]:24492 "EHLO el-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755251AbXLQRsB (ORCPT ); Mon, 17 Dec 2007 12:48:01 -0500 Received: by el-out-1112.google.com with SMTP id v27so355995ele.23 for ; Mon, 17 Dec 2007 09:48:00 -0800 (PST) In-Reply-To: <20071217090000.64499fba@deepthought> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Dec 17, 2007 12:00 PM, Stephen Hemminger wrote: > > > > > > > > a) drivers/net/sky2.c - watchdog_timer. This was showing up high on > > > > Powertop's list of things that cause routine wakeups from idle. After > > > > converting to init_timer_deferrable() the wakeups went down and this one > > > > no longer shows up in powertop's list. 25% reduction. > > This surprises me because it is a 1 hz timer and uses round_jiffies() in > the current kernel. I am using the current git and I already have low wakeups per second to begin with - 5-7 and out of that 25% are attributed to sky2. Not sure if that matches up with the 1 hz + round_jiffies() logic. But is it conceptually ok to make this deferrable? I suppose yes as it's just a watchdog that checks if the link is up and delaying that would not make a difference? Thanks Parag