* mmap performance of reserved top sdram in powerpc platform
@ 2010-01-28 14:47 Lonsn
0 siblings, 0 replies; only message in thread
From: Lonsn @ 2010-01-28 14:47 UTC (permalink / raw)
To: linuxppc-dev; +Cc: lonsn
Hi all:
I have reserved top 128MBytes sdram for PCI DMA usage. External PCI
master sends data to top sdram and then wake up user space app.
User space use /dev/mem and mmap to access this region and then send
them to network using socket.
I found send speed of memory data in /dev/mem to network is very slow.
(300Mbits/s)
If I malloc memory data in user space and then send to network, the
speed is much higher. (750Mbits/s).
I know the reason is the sdram in /dev/mem marked as un-cached.
How can I set the top sdram as cached to impove performance and be
sure that the data is coherent.
My kernel version is DENX-v2.6.32.
Thanks.
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2010-01-28 14:47 UTC | newest]
Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-01-28 14:47 mmap performance of reserved top sdram in powerpc platform Lonsn
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).