From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755319AbbAITYM (ORCPT ); Fri, 9 Jan 2015 14:24:12 -0500 Received: from mail-ig0-f177.google.com ([209.85.213.177]:49661 "EHLO mail-ig0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751064AbbAITYK (ORCPT ); Fri, 9 Jan 2015 14:24:10 -0500 MIME-Version: 1.0 In-Reply-To: <1420773280.5340.16.camel@marge.simpson.net> References: <1420694794.5279.33.camel@marge.simpson.net> <1420773280.5340.16.camel@marge.simpson.net> Date: Fri, 9 Jan 2015 11:24:10 -0800 Message-ID: Subject: Re: sched_yield() call on Linux Kernel 2.6.39 is not behaving correct From: Yogesh Ahire To: Mike Galbraith Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thank you Mike. I didn't get what you mean by saying "its gona try to yield for one hell of a long time before it succeeds". On Thu, Jan 8, 2015 at 7:14 PM, Mike Galbraith wrote: > On Thu, 2015-01-08 at 10:00 -0500, Yogesh Ahire wrote: >> Thank you Mike. But I can see there are tasks with same priority and >> are runnable waiting for CPU, following is the output of >> /proc/sched_debug where you can see that the task "symphonyapp" >> continuously calls sched_yield() but there are other tasks which are >> ready to run are not getting CPU and are queued back. > > Something terminally bad happened. With that tasks vruntime (tree-key), > it's gonna try to yield for one hell of a long time before it succeeds. > > -Mike >