From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Magenheimer Subject: RE: Even faster page copy for Xen? Date: Thu, 15 Jul 2010 16:36:12 -0700 (PDT) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser , Jan Beulich Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org I wasn't sure about that... Jan's patch to speed up copy_page (by 12%) went in before tmem was in-tree, so I assumed otherwise. Clearly my interest is for tmem, especially if 2x-4x improvement is possible, but if there really is no significant advantage for non-tmem code, I will put it on my list... for sometime in the next century when I am a good x86 assembly programmer :-) > -----Original Message----- > From: Keir Fraser [mailto:keir.fraser@eu.citrix.com] > Sent: Thursday, July 15, 2010 3:35 PM > To: Dan Magenheimer; Jan Beulich > Cc: xen-devel@lists.xensource.com > Subject: Re: Even faster page copy for Xen? >=20 > It has to be said, possibly tmem excepted, there is very little page > copying > in Xen. >=20 > -- Keir >=20 > On 15/07/2010 19:15, "Dan Magenheimer" > wrote: >=20 > > Hi Jan, Keir -- > > > > My x86 assembly skills are much too poor to carefully evaluate > > and, if of value, implement this in Xen but given your previous > > interest, such as: > > > > http://xenbits.xensource.com/xen-unstable.hg?rev/8de4b4e9a435 > > > > the following might be worth looking at. > > > > Intel has just posted memcpy improvements for glibc for recent > > popular Intel processor families here: > > > > http://article.gmane.org/gmane.comp.lib.glibc.alpha/15278 > > > > The preface to the above patch looks very enticing... > > > > Semi-related, I wonder if you know, if there were a > > "copy_page_from_other_node()" to be used if the > > caller is fairly sure that the page is being copied > > between nodes, could this be made significantly faster > > than a normal copy_page()? > > > > Thanks, > > Dan >=20 >=20