From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f200.google.com (mail-qt0-f200.google.com [209.85.216.200]) by kanga.kvack.org (Postfix) with ESMTP id 9E2FB6B0038 for ; Fri, 12 May 2017 12:19:41 -0400 (EDT) Received: by mail-qt0-f200.google.com with SMTP id v27so20633409qtg.6 for ; Fri, 12 May 2017 09:19:41 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id j42si799279qtj.224.2017.05.12.09.19.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 12 May 2017 09:19:40 -0700 (PDT) Date: Fri, 12 May 2017 13:19:16 -0300 From: Marcelo Tosatti Subject: Re: [patch 2/2] MM: allow per-cpu vmstat_threshold and vmstat_worker configuration Message-ID: <20170512161915.GA4185@amt.cnet> References: <20170425135717.375295031@redhat.com> <20170425135846.203663532@redhat.com> <20170502102836.4a4d34ba@redhat.com> <20170502165159.GA5457@amt.cnet> <20170502131527.7532fc2e@redhat.com> <20170512122704.GA30528@amt.cnet> <20170512154026.GA3556@amt.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Luiz Capitulino , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Rik van Riel , Linux RT Users , cmetcalf@mellanox.com On Fri, May 12, 2017 at 11:07:48AM -0500, Christoph Lameter wrote: > On Fri, 12 May 2017, Marcelo Tosatti wrote: > > > In our case, vmstat updates are very rare (CPU is dominated by DPDK). > > What is the OS doing on the cores that DPDK runs on? I mean we here can > clean a processor of all activities and are able to run for a long time > without any interruptions. > > Why would you still let the OS do things on that processor? If activities > by the OS are required then the existing NOHZ setup already minimizes > latency to a short burst (and Chris Metcalf's work improves on that). > > > What exactly is the issue you are seeing and want to address? I think we > have similar aims and as far as I know the current situation is already > good enough for what you may need. You may just not be aware of how to > configure this. I want to disable vmstat worker thread completly from an isolated CPU. Because it adds overhead to a latency target, target which the lower the better. > I doubt that doing inline updates will do much good compared to what we > already have and what the dataplan mode can do. Can the dataplan mode disable vmstat worker thread completly on a given CPU? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org