From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754230AbbAIDOp (ORCPT ); Thu, 8 Jan 2015 22:14:45 -0500 Received: from mail-we0-f178.google.com ([74.125.82.178]:63656 "EHLO mail-we0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751050AbbAIDOo (ORCPT ); Thu, 8 Jan 2015 22:14:44 -0500 X-Greylist: delayed 78485 seconds by postgrey-1.27 at vger.kernel.org; Thu, 08 Jan 2015 22:14:44 EST Message-ID: <1420773280.5340.16.camel@marge.simpson.net> Subject: Re: sched_yield() call on Linux Kernel 2.6.39 is not behaving correct From: Mike Galbraith To: Yogesh Ahire Cc: linux-kernel@vger.kernel.org Date: Fri, 09 Jan 2015 04:14:40 +0100 In-Reply-To: References: <1420694794.5279.33.camel@marge.simpson.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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