Messages in this thread | | | Date | Sun, 5 Mar 2006 04:43:25 +0300 | From | Evgeniy Polyakov <> | Subject | Re: [PATCH 0/8] Intel I/O Acceleration Technology (I/OAT) |
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On Sat, Mar 04, 2006 at 01:41:44PM -0800, David S. Miller (davem@davemloft.net) wrote: > From: Jan Engelhardt <jengelh@linux01.gwdg.de> > Date: Sat, 4 Mar 2006 19:46:22 +0100 (MET) > > > Does this buy the normal standard desktop user anything? > > Absolutely, it optimizes end-node performance.
It really depends on how it is used. According to investigation made for kevent based FS AIO reading, get_user_pages() performange graph looks like sqrt() function with plato starting on about 64-80 pages on Xeon 2.4Ghz with 1Gb of ram, while memcopy() is linear, so it can be noticebly slower than copy_to_user() if get_user_pages() is used aggressively, so userspace application must reuse the same, already grabbed buffer for maximum performance, but Intel folks did not provide theirs usage case and any benchmarks as far as I know.
-- Evgeniy Polyakov - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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