Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752581AbbGMSS0 (ORCPT ); Mon, 13 Jul 2015 14:18:26 -0400 Received: from foss.arm.com ([217.140.101.70]:58924 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752465AbbGMSSA (ORCPT ); Mon, 13 Jul 2015 14:18:00 -0400 Date: Mon, 13 Jul 2015 19:17:55 +0100 From: Will Deacon To: David Daney Cc: "linux-arm-kernel@lists.infradead.org" , Catalin Marinas , "linux-kernel@vger.kernel.org" , Robert Richter , Andrew Morton , David Daney Subject: Re: [PATCH 3/3] arm64, mm: Use IPIs for TLB invalidation. Message-ID: <20150713181755.GP2632@arm.com> References: <1436646323-10527-1-git-send-email-ddaney.cavm@gmail.com> <1436646323-10527-4-git-send-email-ddaney.cavm@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1436646323-10527-4-git-send-email-ddaney.cavm@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1071 Lines: 30 On Sat, Jul 11, 2015 at 09:25:23PM +0100, David Daney wrote: > From: David Daney > > Most broadcast TLB invalidations are unnecessary. So when > invalidating for a given mm/vma target the only the needed CPUs via > and IPI. > > For global TLB invalidations, also use IPI. > > Tested on Cavium ThunderX. > > This change reduces 'time make -j48' on kernel from 139s to 116s (83% > as long). Any idea *why* you're seeing such an improvement? Some older kernels had a bug where we'd try to flush a negative (i.e. huge) range by page, so it would be nice to rule that out. I assume these measurements are using mainline? Having TLBI responsible for that amount of a kernel build doesn't feel right to me and doesn't line-up with the profiles I'm used to seeing. You have 16-bit ASIDs, right? Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/