From: "David S. Miller" <davem@davemloft.net>
To: johnpol@2ka.mipt.ru
Cc: jengelh@linux01.gwdg.de, christopher.leech@intel.com,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 0/8] Intel I/O Acceleration Technology (I/OAT)
Date: Sat, 04 Mar 2006 18:08:19 -0800 (PST) [thread overview]
Message-ID: <20060304.180819.44228793.davem@davemloft.net> (raw)
In-Reply-To: <20060305014324.GA20026@2ka.mipt.ru>
From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Date: Sun, 5 Mar 2006 04:43:25 +0300
> 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.
Of course, and programming the DMA controller has overhead
as well. This is why would would not use I/O AT with small
transfer sizes.
next prev parent reply other threads:[~2006-03-05 2:08 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-03 21:40 [PATCH 0/8] Intel I/O Acceleration Technology (I/OAT) Chris Leech
2006-03-03 21:42 ` [PATCH 1/8] [I/OAT] DMA memcpy subsystem Chris Leech
2006-03-04 1:40 ` David S. Miller
2006-03-06 19:39 ` Chris Leech
2006-03-04 19:20 ` Benjamin LaHaise
2006-03-06 19:48 ` Chris Leech
2006-03-03 21:42 ` [PATCH 3/8] [I/OAT] Setup the networking subsystem as a DMA client Chris Leech
2006-03-03 21:42 ` [PATCH 4/8] [I/OAT] Utility functions for offloading sk_buff to iovec copies Chris Leech
2006-03-05 7:15 ` Andrew Morton
2006-03-03 21:42 ` [PATCH 5/8] [I/OAT] Structure changes for TCP recv offload to I/OAT Chris Leech
2006-03-05 7:19 ` Andrew Morton
2006-03-03 21:42 ` [PATCH 6/8] [I/OAT] Rename cleanup_rbuf to tcp_cleanup_rbuf and make non-static Chris Leech
2006-03-03 21:42 ` [PATCH 7/8] [I/OAT] Add a sysctl for tuning the I/OAT offloaded I/O threshold Chris Leech
2006-03-04 11:22 ` Alexey Dobriyan
2006-03-05 7:21 ` Andrew Morton
2006-03-03 21:42 ` [PATCH 8/8] [I/OAT] TCP recv offload to I/OAT Chris Leech
2006-03-04 16:39 ` Pavel Machek
2006-03-04 23:18 ` Greg KH
2006-03-06 19:28 ` Chris Leech
2006-03-05 7:30 ` Andrew Morton
2006-03-05 8:45 ` Andrew Morton
2006-03-05 10:27 ` David S. Miller
2006-03-06 19:36 ` Chris Leech
2006-03-03 22:27 ` [PATCH 0/8] Intel I/O Acceleration Technology (I/OAT) Jeff Garzik
2006-03-03 22:39 ` Chris Leech
2006-03-03 22:45 ` Jeff Garzik
2006-03-04 11:35 ` Evgeniy Polyakov
2006-03-05 8:09 ` Andrew Morton
2006-03-05 9:02 ` Discourage duplicate symbols in the kernel? [Was: Intel I/O Acc...] Sam Ravnborg
2006-03-05 9:18 ` Andrew Morton
2006-03-06 19:56 ` Chris Leech
2006-03-03 22:58 ` [PATCH 0/8] Intel I/O Acceleration Technology (I/OAT) Kumar Gala
2006-03-03 23:32 ` Chris Leech
2006-03-04 18:46 ` Jan Engelhardt
2006-03-04 21:41 ` David S. Miller
2006-03-05 1:43 ` Evgeniy Polyakov
2006-03-05 2:08 ` David S. Miller [this message]
2006-03-06 17:44 ` Ingo Oeser
2006-03-07 7:44 ` Evgeniy Polyakov
2006-03-07 9:43 ` Ingo Oeser
2006-03-07 10:16 ` Evgeniy Polyakov
-- strict thread matches above, loose matches on Subject: below --
2006-03-11 2:27 Chris Leech
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