From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Thu, 20 Nov 2003 01:24:08 +0000 Subject: Re: [PATCH] - sched_clock() broken for ia64 SN platform Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Wed, 19 Nov 2003 16:56:23 -0800 (PST), John Hawkes said: John> We might instead want to implement a more general scheme, John> along the lines of what is done by (struct time_interpolator), John> to provide a framework to solve this for other architectures John> that have "drifty" non-default timebases. My sense is that with a bit of thinking, it would be possible to come up with a solution that allows even drifty platforms to use ITC for sched_clock()---it serves very a specific purpose in the scheduler and scalability is key and perfect accuracy is not (unlike for gettimeofday). I don't think anything that goes out to read a single (shared) platform counter will be sufficiently scalable to the number of CPUs you guys are talking about. But yes, it would be much more effort than just adding Yet Another Callback. The rewards would be bigger, though, too... --david