[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [PATCH] x86: add SSE-based copy_page()
Hi Dan, clflush(flush a cache line; you may need a loop to flush a page.) or wbinvd(flush all the caches) should be what you need to flush caches on x86. Thanks, -- Dexuan -----Original Message----- From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Dan Magenheimer Sent: 2008年11月14日 7:42 To: Jan Beulich Cc: xen-devel@xxxxxxxxxxxxxxxxxxx Subject: RE: [Xen-devel] [PATCH] x86: add SSE-based copy_page() > This very much depends on whether the page(s) are in any caches - in > the general case (e.g. when dealing with large sets of data, or data > just read from disk), you'd expect both pages (source and destination) > not to be in any cache. This is where using the streaming instructions > helps. > > However, when dealing with a small set of pages (or even just a single > source/destination pair), you'd easily run entirely on L1 or > L2 data, which > certainly performs better using the non-streaming instructions. Is there a way to force-flush-cache on a page full of data? (I knew how to do this once on ia64...) I can easily measure warm-start but am not sure how to measure cold-start without some kind of flush. Thanks, Dan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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