From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Subject: Re: [PATCH RESEND v4] sched/fair: Add advisory flag for borrowing a timeslice Date: Mon, 22 Dec 2014 09:40:43 -0700 Message-ID: <5498498B.90703@oracle.com> References: <1418928259-6311-1-git-send-email-khalid.aziz@oracle.com> <20141218222846.GH30905@twins.programming.kicks-ass.net> <54935842.5020507@oracle.com> <54936562.5070502@oracle.com> <54949BF0.8030403@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-doc-owner@vger.kernel.org To: Thomas Gleixner Cc: Peter Zijlstra , corbet@lwn.net, mingo@redhat.com, hpa@zytor.com, riel@redhat.com, akpm@linux-foundation.org, rientjes@google.com, ak@linux.intel.com, mgorman@suse.de, 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 12/19/2014 04:57 PM, Thomas Gleixner wrote: > On Fri, 19 Dec 2014, Khalid Aziz wrote: >> The queuing problem caused by a task taking a contended lock just before its >> current timeslice is up which userspace app wouldn't know about, is a real >> problem nevertheless. > > We know that already. > >> My patch attempts to avoid the contention in the first >> place. futex with adaptive spinning is a post-contention solution that tries >> to minimize the cost of contention but does nothing to avoid the contention. > > I never said that adaptive spinning can solve that problem. > > If you would have carefuly read what I wrote, you might have noticed, > that I said: > > a proper futex like spin mechanism > > Can you spot the subtle difference between that phrase and 'futex with > adaptive spinning'? > >> Solving this problem using futex can help only if the userspace lock uses >> futex. > > A really fundamentally new and earth shattering insight. > > If you would spend your time to actually digest what maintainers are > telling you, we might make progress on that matter. > > But you prefer to spend your time by repeating yourself and providing > completely useless information. > > What you are missing completely here is that neither me nor other > maintainers involved care about how you spend your time. But we very > much care about the time WE waste with your behaviour. I am sorry that you feel the need to continue to resort to personal attacks even after I made it clear in my last response that I was not going to pursue this patch. There is no possibility of a productive discussion of a solution at this point. I hope someone else can find a solution you find acceptable. Thanks, Khalid