From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Date: Fri, 11 Jan 2008 12:42:37 +0000 Subject: Re: [patch] block: fix blktrace timestamps Message-Id: <20080111124236.GV6258@kernel.dk> List-Id: References: <1199996752.9159.46.camel@lap75545.ornl.gov> <20080110234438.4826f658@inria.fr> <1200020661.5099.3.camel@obelisk.thedillows.org> <20080111090723.GI6258@kernel.dk> <20080111092334.GA8143@elte.hu> <20080111092513.GO6258@kernel.dk> <20080111094205.GE8143@elte.hu> <20080111095654.GR6258@kernel.dk> <20080111102953.GA27223@elte.hu> <20080111122802.GT6258@kernel.dk> In-Reply-To: <20080111122802.GT6258@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ingo Molnar Cc: David Dillow , Guillaume Chazarain , linux-kernel@vger.kernel.org, linux-btrace@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de On Fri, Jan 11 2008, Jens Axboe wrote: > > ktime_get() should have been used instead, which is a proper GTOD > > clocksource. The patch below implements this. > > Will give it a whirl, it looks promising indeed and gets rid of the ugly > cpu sync stuff. What is the cost of ktime_get() compared to > sched_clock()? Works for me - will apply it right now, we can always evaluate any potential performance impact later. It's more important to have a functional blktrace in 2.6.24. Thanks Ingo! -- Jens Axboe