On Wed 2015-05-06 11:45:04, Russell King - ARM Linux wrote: > On Tue, Apr 28, 2015 at 11:28:53AM -0400, Nicolas Pitre wrote: > > On Tue, 28 Apr 2015, Russell King - ARM Linux wrote: > > > > > On Fri, Apr 24, 2015 at 03:46:56PM +0200, Geert Uytterhoeven wrote: > > > > So please optimize ARM's _memcpy_fromio(), _memcpy_toio(), and _memset_io(). > > > > That will benefit other drivers on ARM, too. > > > > > > That's not going to happen. > > > > > > I've had a patch which does that, but people are concerned that it changes > > > the behaviour of the functions by changing the access size, which could > > > cause regressions. It seems people are far too worried about that to even > > > consider trying. :( > > > > What about making the optimized implementation available via kconfig? > > I'd prefer not to. My personal feeling is to put the patch in and just be > done with it - these functions are supposed to be used on IO areas which > don't care about access size (in other words, are memory-like rather than > being register-like.) Here's the rather old patch: > > From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> > Subject: [PATCH] ARM: optimize memset_io()/memcpy_fromio()/memcpy_toio() > > If we are building for a LE platform, and we haven't overriden the > MMIO ops, then we can optimize the mem*io operations using the > standard string functions. > > Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> Tested-by: Pavel Machek <pavel@xxxxxx> Acked-by: Pavel Machek <pavel@xxxxxx> Works for me, framebuffer performance is back in "too fast to measure" range. When this is merged, should 981409b25e2a99409b26daa67293ca1cfd5ea0a0 be reverted in -stable? Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
