Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762536AbZAUH1d (ORCPT ); Wed, 21 Jan 2009 02:27:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754876AbZAUH1Z (ORCPT ); Wed, 21 Jan 2009 02:27:25 -0500 Received: from cantor2.suse.de ([195.135.220.15]:49349 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754268AbZAUH1Y (ORCPT ); Wed, 21 Jan 2009 02:27:24 -0500 Date: Wed, 21 Jan 2009 08:27:18 +0100 From: Nick Piggin To: Ingo Molnar Cc: Jeremy Fitzhardinge , Linux Kernel Mailing List , Linus Torvalds , hpa@zytor.com, jeremy@xensource.com, chrisw@sous-sol.org, zach@vmware.com, rusty@rustcorp.com.au, Andrew Morton , Xen-devel Subject: Re: lmbench lat_mmap slowdown with CONFIG_PARAVIRT Message-ID: <20090121072718.GN24891@wotan.suse.de> References: <20090120110542.GE19505@wotan.suse.de> <20090120112634.GA20858@elte.hu> <20090120140324.GA26424@elte.hu> <49763806.5090009@goop.org> <20090120205653.GA19710@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090120205653.GA19710@elte.hu> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1149 Lines: 29 On Tue, Jan 20, 2009 at 09:56:53PM +0100, Ingo Molnar wrote: > > * Jeremy Fitzhardinge wrote: > >> | 50234816 | 51303520 cache references +2.12% > >> | 5428258 | 5583728 cache misses +2.86% > >> > > > > Is this I or D, or combined? > > That's last-level-cache references+misses (L2 cache): > > Bit Position Event Name UMask Event Select > CPUID.AH.EBX > 3 LLC Reference 4FH 2EH > 4 LLC Misses 41H 2EH Oh, _llc_ references/misses? Ouch. You have, what 32K L1I, 32K L1D, and 4MB L2? And even this microbenchmark is seeing increased L2 misses by nearly 3%. Hmm, I wonder where that is coming from? Instruction fetches? It would be interesting to see how "the oltp" benchmark fares with CONFIG_PARAVIRT turned on. That workload lives and dies by the cache :) -- 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/