Re: SIGSTKSZ is now a run-time variable

[Scott Lurndal]

On Tue, Mar 09, 2021 at 08:58:38PM +0100, Bruno Haible via austin-group-l at 
The Open Group 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?
>    1.2) What value of MINSIGSTKSZ is needed for AVX-512F support?
>    1.3) Will the trend to larger MINSIGSTKSZ values continue for Intel
>         processors?

It's not just Intel processors.

64-bit ARM processors that support scalable vectors (SVE) support
vectors of up to 2084 bits, and they have 32 vector registers which would
require 8Kbytes for the SVE state alone if the implementation supports
the full 2kbits.

scott