[J-core] [musl] Re: Aligned copies and cacheline conflicts?

Rich Felker dalias at libc.org
Wed Sep 14 22:36:45 EDT 2016


On Wed, Sep 14, 2016 at 07:58:52PM -0500, Rob Landley wrote:
> On 09/14/2016 07:34 PM, Rich Felker wrote:
> > I could put a fork of memcpy.c in sh/memcpy.c and work on it there and
> > only merge it back to the shared one if others test it on other archs
> > and find it beneficial (or at least not harmful).
> 
> Both musl and the kernel need it. And yes at the moment it seems
> architecture-specific, but it's a _big_ performance difference...

I actually think it's justifiable to have in the generic C memcpy,
from a standpoint that the generic C shouldn't assume an N-way (N>1,
i.e. not direct mapped) associative cache. Just need to make sure
changing it doesn't make gcc do something utterly idiotic for other
archs, I guess. I'll take a look at this.

Rich


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