From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Mon, 24 Feb 2003 19:12:39 +0000 Subject: [Linux-ia64] Re: strange performance behaviour with floats 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 Mon, 24 Feb 2003 13:25:12 +1100, Keith Owens said: Keith> On Sun, 23 Feb 2003 18:16:57 -0800, Keith> David Mosberger wrote: >> Let me say this again: you _don't_ want a single-cycle loop. You want >> a 2-cycle loop that gets twice the work done as a 1-cycle loop. That >> is, you'd want to decrement the loop counter by 2, compare it against >> zero, and branch if it's not zero yet, all the while making sure you >> get a 2-cycle loop. Keith> Now I see what you are getting at, sorry for the confusion. No problem. ;-) Keith> Of course, the fact that udelay() does not use bogomips at all makes Keith> the whole question irrelevant. We now return you to our regularly Keith> scheduled delay loop :) True, but the code gcc generates for the BogoMIPS loops basically looks identical to the one for udelay(), so the comments still apply. --david