From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kirill Tkhai Subject: Re:[PATCH] sched/rt: Decrease number of calls of push_rt_task() in push_rt_tasks() Date: Tue, 05 Feb 2013 14:27:04 +0400 Message-ID: <798741360060024@web12h.yandex.ru> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Steven Rostedt , linux-kernel@vger.kernel.org, Ingo Molnar , Peter Zijlstra , linux-rt-users To: Honghui Zhang Return-path: Received: from forward3h.mail.yandex.net ([84.201.187.148]:44436 "EHLO forward3h.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750960Ab3BEK1K (ORCPT ); Tue, 5 Feb 2013 05:27:10 -0500 Sender: linux-rt-users-owner@vger.kernel.org List-ID: > On 2013/2/5 15:22, Kirill Tkhai wrote: > >>> Suppose we have a large number of cpus(say 4096), with the last one running >>> a low-priority task on it. Is it possible with this patch we will never reach >>> the last cpu in case that previous cpu has complete the pulled task? >> >> Yes. But this patch is about several pushable tasks on the same cpu. >> >> Kirill > > Maybe I haven't make myself understood, but in that case, there will be a higher-priority > task in the runqueue of the pushing cpu, and a lower-priority task running in the last cpu > which could not be preempt by push_rt_task(), I don't think it's acceptable. Sure, I tried to prevent the fact of call of this function with locks of spinlocks etc. It may be useful on system like 2 CPU, but it's not necessary for large systems. I'm not persist in this. Kirill > > Hans > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html --