bzero & bcopy alignment

Luigi Rizzo rizzo at icir.org
Sun Jan 21 22:21:44 UTC 2007


On Sun, Jan 21, 2007 at 10:10:23PM +0000, Poul-Henning Kamp wrote:
> In message <20070121140019.A83688 at xorpc.icir.org>, Luigi Rizzo writes:
> >On Sun, Jan 21, 2007 at 10:41:09PM +0100, Ivan Voras wrote:
> >> Following recent discussion on alignment of bzero() and bcopy(), I've
> >> added some statistics collecting code to bzero() and bcopy() for
> >> practice (on a RELENG_6 box), and here are the cumulative results for
> >> argument alignment:
> >
> >i think these profiles depend heavily on the hardware
> >and usage patterns.
> 
> Undoubtedly, but on the other hand, a lot of them operate on
> structs and other data laid out by the compiler, so the
> unaligned calls are special cases.

and that is why i suggested to instrument the functions to record
where in the source the unaligned functions are called, so we can
figure out whether it is something unavoidable or something
that can be fixed.

	cheers
	luigi


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