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[192.222.189.155]) by smtp.gmail.com with ESMTPSA id n66sm9496354qkc.36.2019.05.08.10.49.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 08 May 2019 10:49:18 -0700 (PDT) Date: Wed, 8 May 2019 13:49:09 -0400 From: Julien Desfossez To: Aaron Lu Cc: Vineeth Remanan Pillai , Phil Auld , Nishanth Aravamudan , Peter Zijlstra , Tim Chen , mingo@kernel.org, tglx@linutronix.de, pjt@google.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, subhra.mazumdar@oracle.com, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, Aaron Lu , Aubrey Li , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini Subject: Re: [RFC PATCH v2 00/17] Core scheduling v2 Message-ID: <20190508174909.GA18516@sinkpad> References: <20190423180238.GG22260@pauld.bos.csb> <20190423184527.6230-1-vpillai@digitalocean.com> <20190429035320.GB128241@aaronlu> <20190506193937.GA10264@sinkpad> <20190508023009.GA89792@aaronlu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190508023009.GA89792@aaronlu> X-Mailer: Mutt 1.5.24 (2015-08-30) User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08-May-2019 10:30:09 AM, Aaron Lu wrote: > On Mon, May 06, 2019 at 03:39:37PM -0400, Julien Desfossez wrote: > > On 29-Apr-2019 11:53:21 AM, Aaron Lu wrote: > > > This is what I have used to make sure no two unmatched tasks being > > > scheduled on the same core: (on top of v1, I thinks it's easier to just > > > show the diff instead of commenting on various places of the patches :-) > > > > We imported this fix in v2 and made some small changes and optimizations > > (with and without Peter’s fix from https://lkml.org/lkml/2019/4/26/658) > > and in both cases, the performance problem where the core can end up > > By 'core', do you mean a logical CPU(hyperthread) or the entire core? No I really meant the entire core. I’m sorry, I should have added a little bit more context. This relates to a performance issue we saw in v1 and discussed here: https://lore.kernel.org/lkml/20190410150116.GI2490@worktop.programming.kicks-ass.net/T/#mb9f1f54a99bac468fc5c55b06a9da306ff48e90b We proposed a fix that solved this, Peter came up with a better one (https://lkml.org/lkml/2019/4/26/658), but if we add your isolation fix as posted above, the same problem reappears. Hope this clarifies your ask. I hope that we did not miss anything crucial while integrating your fix on top of v2 + Peter’s fix. The changes are conceptually similar, but we refactored it slightly to make the logic clear. Please have a look and let us know Thanks, Julien