This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH] Add ifunc memcpy and memmove for aarch64
On Thursday 09 February 2017 04:20 PM, Szabolcs Nagy wrote:
> this is a trap into the kernel at every process startup
>
> since this is called very early (dynamic linking case
> above, static linking case below) i wonder if there
> could be a way for the user to request midr_el1==0
> unconditionally (avoiding the overhead and making
> sure the most generic implementation is used)
Well you could use tunables to avoid it, but then if a single trap is a
problem for you then the tunables infra is going to be just as expensive.
Why is a single trap at startup such a concern though?
> is there something like that on other targets?
H.J. Lu had a patch to override IFUNCs using (what will now be) a
tunable but that patch did not make progress. I hope it will now since
I too am interested in overriding IFUNC selection using tunables. But
then this would be an orthogonal discussion to avoiding the trap since
the goals of both are different.
Siddhesh