Re: SIGSTKSZ is now a run-time variable

[H.J. Lu]

On Tue, Mar 9, 2021 at 12:27 PM Bruno Haible <bruno@clisp.org> wrote:
>
> Eric Blake wrote:
> > I can open a defect against POSIX if we decide that is needed, but want
> > some consensus first on whether it is glibc's change that went too far,
> > or POSIX's requirements that are too restrictive for what glibc wants to do.
>
> Thanks for opening the discussion, Eric.
>
> Here are a couple of questions, to understand the motivation and the possible
> alternative solutions to the problem:
>
> 1) As far as I understand, the issue occurs with certain x86 or x86_64
>    processors.
>
>    1.1) What has been the value of MINSIGSTKSZ on x86 and x86_64 so far?

It is 2048 bytes in glibc 2.32.

>    1.2) What value of MINSIGSTKSZ is needed for AVX-512F support?

For i686, it is 3628 bytes.   For x86-64, it is 3212 bytes.

>    1.3) Will the trend to larger MINSIGSTKSZ values continue for Intel
>         processors?

With 8 1K Tile registers, we need another 8K.   I can't tell you how big
we will need in 10 years.

-- 
H.J.