[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: Even faster page copy for Xen?
>>> On 15.07.10 at 20:15, Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> wrote: > 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... I'm not sure how much of this applies to the much more specific case of copying pages... Additionally, I don't think trying to use XMM registers in Xen would be a good idea. > 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()? I would think that this should mostly be taken care of by using non-temporal stores (non-temporal loads unfortunately aren't available without using XMM registers). The only other meaningful tuning one could do would be to increase the prefetch distances and grow the distance between loads and stores. The latter would require the use of more registers and hence have other drawbacks. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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