From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [Qemu-devel] Re: [PATCH v2] qemu-kvm: Speed up of the dirty-bitmap-traveling Date: Wed, 10 Feb 2010 17:00:56 +0100 Message-ID: <4B72D838.9060603@suse.de> References: <4B728FF9.6010707@lab.ntt.co.jp> <4B72B28E.6010801@redhat.com> <4B72D69D.7050005@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Cc: Avi Kivity , OHMURA Kei , mtosatti@redhat.com, "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , Anthony Liguori To: Anthony Liguori Return-path: Received: from cantor.suse.de ([195.135.220.2]:35921 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755203Ab0BJQBA (ORCPT ); Wed, 10 Feb 2010 11:01:00 -0500 In-Reply-To: <4B72D69D.7050005@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: Anthony Liguori wrote: > On 02/10/2010 07:20 AM, Avi Kivity wrote: > >> On 02/10/2010 12:52 PM, OHMURA Kei wrote: >> >> >>> dirty-bitmap-traveling is carried out by byte size in qemu-kvm.c. >>> But We think that dirty-bitmap-traveling by long size is faster than by byte >>> size especially when most of memory is not dirty. >>> >>> --- a/bswap.h >>> +++ b/bswap.h >>> @@ -209,7 +209,6 @@ static inline void cpu_to_be32wu(uint32_t *p, uint32_t v) >>> #define cpu_to_32wu cpu_to_le32wu >>> #endif >>> >>> -#undef le_bswap >>> #undef be_bswap >>> #undef le_bswaps >>> >>> >>> >> Anthony, is it okay to export le_bswap this way, or will you want >> leul_to_cpu()? >> >> > > kvm_get_dirty_pages_log_range() is kvm-specific code. We're guaranteed > that when we're using kvm, target byte order == host byte order. > > So is it really necessary to use a byte swapping function at all? > On PPC the bitmap is Little Endian. Alex