From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756676Ab1LWKiR (ORCPT ); Fri, 23 Dec 2011 05:38:17 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:33362 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756537Ab1LWKiP (ORCPT ); Fri, 23 Dec 2011 05:38:15 -0500 Date: Fri, 23 Dec 2011 11:36:20 +0100 From: Ingo Molnar To: Nikunj A Dadhania Cc: Avi Kivity , peterz@infradead.org, linux-kernel@vger.kernel.org, vatsa@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com Subject: Re: [RFC PATCH 0/4] Gang scheduling in CFS Message-ID: <20111223103620.GD4749@elte.hu> References: <20111219083141.32311.9429.stgit@abhimanyu.in.ibm.com> <20111219112326.GA15090@elte.hu> <87sjke1a53.fsf@abhimanyu.in.ibm.com> <4EF1B85F.7060105@redhat.com> <877h1o9dp7.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <877h1o9dp7.fsf@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Nikunj A Dadhania wrote: > Here some interesting perf reports from inside the guest: > > Baseline: > 29.79% ebizzy [kernel.kallsyms] [k] native_flush_tlb_others > 18.70% ebizzy libc-2.12.so [.] __GI_memcpy > 7.23% ebizzy [kernel.kallsyms] [k] get_page_from_freelist > 5.38% ebizzy [kernel.kallsyms] [k] __do_page_fault > 4.50% ebizzy [kernel.kallsyms] [k] ____pagevec_lru_add > 3.58% ebizzy [kernel.kallsyms] [k] default_send_IPI_mask_logical > 3.26% ebizzy [kernel.kallsyms] [k] native_flush_tlb_single > 2.82% ebizzy [kernel.kallsyms] [k] handle_pte_fault > 2.16% ebizzy [kernel.kallsyms] [k] kunmap_atomic > 2.10% ebizzy [kernel.kallsyms] [k] _spin_unlock_irqrestore > 1.90% ebizzy [kernel.kallsyms] [k] down_read_trylock > 1.65% ebizzy [kernel.kallsyms] [k] __mem_cgroup_commit_charge.clone.4 > 1.60% ebizzy [kernel.kallsyms] [k] up_read > 1.24% ebizzy [kernel.kallsyms] [k] __alloc_pages_nodemask > > Gang: > 22.53% ebizzy libc-2.12.so [.] __GI_memcpy > 9.73% ebizzy [kernel.kallsyms] [k] ____pagevec_lru_add > 8.22% ebizzy [kernel.kallsyms] [k] get_page_from_freelist > 7.80% ebizzy [kernel.kallsyms] [k] default_send_IPI_mask_logical > 7.68% ebizzy [kernel.kallsyms] [k] native_flush_tlb_others > 6.22% ebizzy [kernel.kallsyms] [k] __do_page_fault > 5.54% ebizzy [kernel.kallsyms] [k] native_flush_tlb_single > 4.44% ebizzy [kernel.kallsyms] [k] _spin_unlock_irqrestore > 2.90% ebizzy [kernel.kallsyms] [k] kunmap_atomic > 2.78% ebizzy [kernel.kallsyms] [k] __mem_cgroup_commit_charge.clone.4 > 2.76% ebizzy [kernel.kallsyms] [k] handle_pte_fault > 2.16% ebizzy [kernel.kallsyms] [k] __mem_cgroup_uncharge_common > 1.59% ebizzy [kernel.kallsyms] [k] down_read_trylock > 1.43% ebizzy [kernel.kallsyms] [k] up_read > > I see the main difference between both the reports is: > native_flush_tlb_others. So it would be important to figure out why ebizzy gets into so many TLB flushes and why gang scheduling makes it go away. Thanks, Ingo