Re: Ping: [Patch] aarch64: Thunderx specific memcpy and memmove

[Steve Ellcey <sellcey@cavium.com>]

On Wed, 2017-05-24 at 18:04 +0100, Szabolcs Nagy wrote:

> - i don't know if you plan to make more changes to the thunderx
> memcpy, if prefetching is the only change then it's likely that
> we can agree on a generic version that's good enough.  if you
> do plan to make further changes, then keep in mind that we try
> to have same/similar generic memcpy across c runtimes and if
> your change is good for generic we might not be able to use the
> code outside of glibc (so newlib, bionic, freebsd,.. memcpy
> would diverge)

I am not looking at any more changes to the thunderx memcpy but someone
here is working on a thunderx2 memcpy so I do expect a third version
of memcpy at some point.

> - non-thunderx systems are affected: static linked code using
> memcpy will start to go through an indirection (iplt) instead
> of direct call. if there are complaints about it or other ifunc
> related issues come up, then again we will have to reconsider it.
> 
> so the patch can go in with an understanding that it may go out.

I understand that we may have to look at issues like this in the
future, though building glibc without multiarch enabled should provide
an alternative to those who don't want IFUNC functionality.

Steve Ellcey
sellcey@cavium.com