From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: Windows Server 2008R2 KVM guest performance issues Date: Tue, 27 Aug 2013 09:18:00 +0200 Message-ID: <521C52A8.40801@redhat.com> References: <521BA934.3050507@gameservers.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Brian Rak Return-path: Received: from mail-wi0-f179.google.com ([209.85.212.179]:58888 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752163Ab3H0HSG (ORCPT ); Tue, 27 Aug 2013 03:18:06 -0400 Received: by mail-wi0-f179.google.com with SMTP id ez12so184507wid.0 for ; Tue, 27 Aug 2013 00:18:05 -0700 (PDT) In-Reply-To: <521BA934.3050507@gameservers.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 26/08/2013 21:15, Brian Rak ha scritto: > > Samples: 62M of event 'cycles', Event count (approx.): 642019289177 > 64.69% [kernel] [k] _raw_spin_lock > 2.59% qemu-system-x86_64 [.] 0x00000000001e688d > 1.90% [kernel] [k] native_write_msr_safe > 0.84% [kvm] [k] vcpu_enter_guest > 0.80% [kernel] [k] __schedule > 0.77% [kvm_intel] [k] vmx_vcpu_run > 0.68% [kernel] [k] effective_load > 0.65% [kernel] [k] update_cfs_shares > 0.62% [kernel] [k] _raw_spin_lock_irq > 0.61% [kernel] [k] native_read_msr_safe > 0.56% [kernel] [k] enqueue_entity Can you capture the call graphs, too (perf record -g)? > I've captured 20,000 lines of kvm trace output. This can be found > https://gist.github.com/devicenull/fa8f49d4366060029ee4/raw/fb89720d34b43920be22e3e9a1d88962bf305da8/trace The guest is doing quite a lot of exits per second, mostly to (a) access the ACPI timer (b) service NMIs. In fact, every NMI is reading the timer too and causing an exit to QEMU. So it is also possible that you have to debug this inside the guest, to see if these exits are expected or not. Paolo