Messages in this thread | | | Date | Fri, 24 Apr 2015 15:29:23 +0200 | From | Pavel Machek <> | Subject | Re: simple framebuffer slower by factor of 20, on socfpga (arm) platform |
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Hi!
On Fri 2015-04-10 12:35:52, Archit Taneja wrote: > >That said, if the fb is in RAM, and is only written by the CPU, I think > >a normal memcpy() for fb_memcpy_fromfb() should be fine... > > I didn't test for performance regressions when I posted this patch. > > A look at _memcpy_fromio in arch/arm/kernel/io.c shows that readb() is used > all the time, even when the source and destination addresses are aligned for > larger reads to be possible. Other archs seem to use readl() or readq() when > they can. Maybe that makes memcpy_fromio slower than the implementation of > memcpy on arm?
Ok, can you prepare a patch for me to try? Or should we just revert the original commit? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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