From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 210721A03F8 for ; Tue, 3 Nov 2015 16:30:33 +1100 (AEDT) Message-ID: <1446528621.17404.33.camel@kernel.crashing.org> Subject: Re: [RFC PATCH 0/7] Remove 4k subpage tracking with hash 64K config From: Benjamin Herrenschmidt To: "Aneesh Kumar K.V" , Paul Mackerras Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org Date: Tue, 03 Nov 2015 16:30:21 +1100 In-Reply-To: <87r3k7u0tf.fsf@linux.vnet.ibm.com> References: <1445371953-9627-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20151029030029.GA31681@fergus.ozlabs.ibm.com> <87r3k7u0tf.fsf@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2015-11-03 at 10:38 +0530, Aneesh Kumar K.V wrote: > I also ran mmtest configs/config-global-dhp__pagealloc-performance > config with changes including this series. (ie, the changes tested > include two patch series, one which change the pte format and this > series). I am attaching the results below. I removed the pagealloc > performance numbers from that because it was giving me all 00 which I > assume is due to systemtap script issue. > > We don't see any performance impact with the series and some of the > performance change is withing the variance of test run as indicated by > the numbers below. We do find less page fault and in some case better > autonuma numbers Did you try under pHyp (ie. hit all those H_READ ?). The easy way to do that is comment out 64K support in htab init to force 4k demotion allways. That would give you an idea of the impact on things like old P4/P5 Cheers, Ben.