From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266222AbUGJMGH (ORCPT ); Sat, 10 Jul 2004 08:06:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266224AbUGJMGH (ORCPT ); Sat, 10 Jul 2004 08:06:07 -0400 Received: from smtp106.mail.sc5.yahoo.com ([66.163.169.226]:19075 "HELO smtp106.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S266223AbUGJMFy (ORCPT ); Sat, 10 Jul 2004 08:05:54 -0400 Message-ID: <40EFDB97.70109@yahoo.com.au> Date: Sat, 10 Jul 2004 22:05:43 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040401 Debian/1.6-4 X-Accept-Language: en MIME-Version: 1.0 To: Ingo Molnar CC: Con Kolivas , Peter Williams , Andrew Morton , Nick Piggin , linux kernel mailing list Subject: Re: Likelihood of rt_tasks References: <40EE6CC2.8070001@kolivas.org> <40EF2FF2.6000001@bigpond.net.au> <40EF354F.9090903@kolivas.org> <20040710111528.GA22265@elte.hu> In-Reply-To: <20040710111528.GA22265@elte.hu> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > the unlikely() check in rt_task() was mainly done because there was a > steady stream of microoptimizations that added unlikely() to rt_task(). > So now we do in everywhere and have removed the unlikely()/likely() > branches from sched.c. It doesnt really matter in real-world terms, but > it will make the common case code (non-RT) a tiny bit more compact. And > i challenge anyone to be able to even measure the difference to an RT > task. > Also, the scenario where it may possibly make a tiny positive contribution (something *very* scheduler bound) would be using non-RT tasks I'd say.