Re: [ping][PATCH, AVX512, x86_64] AVX-512 support in glibc for x86_64

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Thu, Feb 20, 2014 at 10:25 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Wed, Feb 12, 2014 at 4:14 AM, Zamyatin, Igor <igor.zamyatin@intel.com> wrote:
>> Ping!
>>
>>> -----Original Message-----
>>> From: Zamyatin, Igor
>>> Sent: Wednesday, February 05, 2014 1:50 PM
>>> To: Zamyatin, Igor; Joseph Myers
>>> Cc: libc-alpha@sourceware.org; hjl.tools@gmail.com
>>> Subject: RE: [PATCH, AVX512, x86_64] AVX-512 support in glibc for x86_64
>>>
>>> Ping.
>>>
>>> Is it ok for trunk whenever it's allowed to commit?
>>>
>>> Thanks,
>>> Igor
>>>
>>> > -----Original Message-----
>>> > From: libc-alpha-owner@sourceware.org [mailto:libc-alpha-
>>> > owner@sourceware.org] On Behalf Of Zamyatin, Igor
>>> > Sent: Tuesday, January 28, 2014 4:57 PM
>>> > To: Joseph Myers
>>> > Cc: libc-alpha@sourceware.org; hjl.tools@gmail.com
>>> > Subject: RE: [PATCH, AVX512, x86_64] AVX-512 support in glibc for
>>> > x86_64
>>> >
>>> > >
>>> > > On Fri, 24 Jan 2014, Zamyatin, Igor wrote:
>>> > >
>>> > > > Attached patch adds AVX512 (new Intel ISA extension, see e.g.
>>> > > > http://software.intel.com/en-us/intel-isa-
>>> > > extensions?page=1&wapkw=soft
>>> > > > ware%20development%20manual%20avx512#pid-16007-1495
>>> > > > ) support in Glibc for x86_64.
>>> > >
>>> > > Do you plan to add support for i386 as well, or is there a reason no
>>> > > such support is needed (that these registers are call-clobbered and
>>> > > not used for argument passing / return, so libc needs no special
>>> > > knowledge
>>> > of them?)?
>>> > > (Cf. bug 15402 suggesting running the AVX audit tests on i386, which
>>> > > would make sense if they are valid for x86 even if no associated
>>> > > changes to the dynamic linker are needed.)
>>> > >
>>> > > >         * sysdeps/x86_64/tst-audit9.c: New file.
>>> > > >         * sysdeps/x86_64/tst-auditmod9a.c: New file.
>>> > > >         * sysdeps/x86_64/tst-auditmod9b.c: New file.
>>> > >
>>> > > Any new test should have a copyright / license notice immediately
>>> > > following the first line saying what the function of the file is.
>>> >
>>> > Updated patch attached.
>>> >
>>> > Thanks,
>>> > Igor
>>> >
>
> A couple comments:
>
> 1.  i386 audit doesn't support xmm nor ymm registers.  Adding
> xmm/ymm/zmm register support to i386 audit is orthogonal to
> x86-64 audit.   It should be evaluated separately from adding
> zmm register support to x86-64 audit.
> 2. Adding zmm register support to x86-64 ld.so has no performance
> impact on non-threaded applications, except that when LD_AUDIT
> is used.
> 3. Adding zmm register support to _dl_x86_64_save_sse and
> _dl_x86_64_restore_sse will have some overhead. They are
> called only when RTLD_PREPARE_FOREIGN_CALL
> is used.  Among all glibc build/tests, it happens with
>
> /export/build/gnu/glibc/build-x86_64-linux/dlfcn/glrefmain:
> /export/build/gnu/glibc/build-x86_64-linux/elf/constload1:
> /export/build/gnu/glibc/build-x86_64-linux/elf/reldep:
> /export/build/gnu/glibc/build-x86_64-linux/elf/lateglobal:
> /export/build/gnu/glibc/build-x86_64-linux/elf/dblload:
> /export/build/gnu/glibc/build-x86_64-linux/elf/reldep5:
> /export/build/gnu/glibc/build-x86_64-linux/elf/reldep7:
> /export/build/gnu/glibc/build-x86_64-linux/elf/dblunload:
> /export/build/gnu/glibc/build-x86_64-linux/elf/tst-deep1:
> /export/build/gnu/glibc/build-x86_64-linux/elf/unload4:
> /export/build/gnu/glibc/build-x86_64-linux/elf/reldep6:
>
> Do they address all concerns people have?
>

Any feedbacks/comments/objections?


-- 
H.J.