Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933478AbaDVRL7 (ORCPT ); Tue, 22 Apr 2014 13:11:59 -0400 Received: from mail-ve0-f175.google.com ([209.85.128.175]:54822 "EHLO mail-ve0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932737AbaDVRL5 (ORCPT ); Tue, 22 Apr 2014 13:11:57 -0400 MIME-Version: 1.0 In-Reply-To: <5354C8F3.3050504@intel.com> References: <5354C8F3.3050504@intel.com> Date: Tue, 22 Apr 2014 10:11:56 -0700 Message-ID: Subject: Re: [libata/ahci] 8a4aeec8d2d: +138.4% perf-stat.dTLB-store-misses, +37.2% perf-stat.dTLB-load-misses From: Dan Williams To: Jet Chen Cc: Tejun Heo , LKML , lkp@01.org, Fengguang Wu Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 21, 2014 at 12:29 AM, Jet Chen wrote: > HI Dan, > > we noticed the below changes on > > git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata for-next > commit 8a4aeec8d2d6a3edeffbdfae451cdf05cbf0fefd ("libata/ahci: accommodate > tag ordered controllers") Hi, was this on simulated hardware or a real AHCI controller and disk? It does appear this test noticed increased throughput: 203893 ~ 0% +3.7% 211474 ~ 0% TOTAL iostat.sda.wkB/s I wonder if ap->last_tag can be moved to a hotter cacheline, but if throughput goes up I can imagine it throws off the cpu statistics quite a bit. -- 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/