From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: [PATCH v3] sched/fair: Add advisory flag for borrowing a timeslice Date: Tue, 25 Nov 2014 10:46:04 -0700 Message-ID: <1416937564.3512.15.camel@maggy.simpson.net> References: <1416862595-24513-1-git-send-email-khalid.aziz@oracle.com> <1416889208.4335.127.camel@maggy.simpson.net> <54749725.3050307@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <54749725.3050307@oracle.com> Sender: linux-kernel-owner@vger.kernel.org To: Khalid Aziz Cc: Thomas Gleixner , corbet@lwn.net, mingo@redhat.com, hpa@zytor.com, peterz@infradead.org, riel@redhat.com, akpm@linux-foundation.org, rientjes@google.com, ak@linux.intel.com, mgorman@suse.de, liwanp@linux.vnet.ibm.com, raistlin@linux.it, kirill.shutemov@linux.intel.com, atomlin@redhat.com, avagin@openvz.org, gorcunov@openvz.org, serge.hallyn@canonical.com, athorlton@sgi.com, oleg@redhat.com, vdavydov@parallels.com, daeseok.youn@gmail.com, keescook@chromium.org, yangds.fnst@cn.fujitsu.com, sbauer@eng.utah.edu, vishnu.ps@samsung.com, axboe@fb.com, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org List-Id: linux-api@vger.kernel.org On Tue, 2014-11-25 at 07:50 -0700, Khalid Aziz wrote: > It is definitely not an attempt to solve any kind of RT problem. No no, I'm saying that giving certain tasks special dispensations effectively elevates them. Temporarily or otherwise, they play by different rules, will block more deserving tasks, and it's not cut and dried that that blocking will not do more harm than good. Is it a clear win to make say some kworker or other global asset wait when it could have preempted and been gone in usecs? Nope. -Mike