[lkml]   [2006]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 0/8] Intel I/O Acceleration Technology (I/OAT)
On Sat, Mar 04, 2006 at 01:41:44PM -0800, David S. Miller ( wrote:
> From: Jan Engelhardt <>
> 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
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-03-05 02:47    [W:0.148 / U:3.184 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site