On Mon, May 19, 2014 at 10:00:52PM +0000, Rustad, Mark D wrote: > On May 16, 2014, at 2:43 PM, Andi Kleen <a...@firstfloor.org> wrote: > > > From: Andi Kleen <a...@linux.intel.com> > > > > ixgbe_read_reg and ixgbe_write_reg are frequently called and are very big > > because they have complex error handling code. > > Actually, this patch doesn't do anything to ixgbe_write_reg, which would > almost certainly be very bad for performance, but instead changes > ixgbe_write_reg64.
I doubt a few cycles around the write make a lot of difference for MMIO. MMIO is dominated by other things. > The latter is not in a performance-sensitive path, but is only called from > one site, so there is little reason to take it out-of-line. True I moved the wrong one. ixgbe_write_reg 3305 (0.00%) 8 409 > I already have a patch in queue to make ixgbe_read_reg out-of-line, because > it does have a very costly memory footprint inline, as you have found. Please move write_reg too. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
