Ping: [PATCH v4] faster strlen on x64

[Ondřej Bílka]

On Thu, Jun 19, 2014 at 01:43:09PM -0700, H.J. Lu wrote:
> On Sun, Mar 17, 2013 at 11:42 PM, Ondřej Bílka <neleai@seznam.cz> wrote:
> > On Fri, Mar 15, 2013 at 10:29:49AM -0400, Carlos O'Donell wrote:
> >> On 03/15/2013 07:49 AM, Ondřej Bílka wrote:
> >> > On Tue, Mar 12, 2013 at 09:24:07AM -0400, Carlos O'Donell wrote:
> >> >> On 03/11/2013 05:15 AM, Ondřej Bílka wrote:
> >> >>> Carlos, what is you opinion?
> >> >>
> >> >> The patch looks good. I have one last question though.
> >> >>
> >> >> We remove some interesting code in the existing strlen implementations
> >> >> that ensure that strlen calls from libc itself do not go through the PLT.
> >> >>
> >> >> Have you verified that after your changes there are no testsuite regressions
> >> >> in the plt check test or that the internal calls to strlen avoid the PLT?
> >> >>
> >> >> OK to checkin after this additional validation with posted result.
> >> >>
> >> >
> >> > I ran http://sourceware.org/glibc/wiki/Testing/Check-localplt
> >> > elf/checklocalplt.out is empty. I guess this means no regressions.
> >>
> >> Correct.
> >>
> >> Cheers,
> >> Carlos.
> >
> > Commited with obvious resolution of merge conflict in
> > sysdeps/x86-64/multiarch/Makefile.
> 
> This commit:
> 
> commit 37bb363f03d75e5e6f2ca45f2c686a3a0167797e
> Author: Ondrej Bilka <neleai@seznam.cz>
> Date:   Mon Mar 18 07:39:12 2013 +0100
> 
>     Faster strlen on x64.
> 
>  sysdeps/x86_64/multiarch/Makefile                |   6 +-
>  sysdeps/x86_64/multiarch/ifunc-impl-list.c       |  13 -
>  sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S | 232 +++++++-
>  sysdeps/x86_64/multiarch/strcat-ssse3.S          | 316 ++++++++++-
>  sysdeps/x86_64/multiarch/strlen-sse2-no-bsf.S    | 685 -----------------------
>  sysdeps/x86_64/multiarch/strlen-sse2-pminub.S    | 259 ---------
>  sysdeps/x86_64/multiarch/strlen-sse4.S           |  84 ---
>  sysdeps/x86_64/multiarch/strlen.S                |  68 ---
>  sysdeps/x86_64/multiarch/strnlen-sse2-no-bsf.S   |   3 -
>  sysdeps/x86_64/multiarch/strnlen.S               |  57 --
>  sysdeps/x86_64/strcat.S                          |   1 +
>  sysdeps/x86_64/strlen.S                          | 272 ++++++---
>  sysdeps/x86_64/strnlen.S                         |  67 +--
> 
> has no ChangeLog entries.  Since it removed sysdeps/x86_64/multiarch/strlen.S,
> sysdeps/x86_64/multiarch/rtld-strlen.S became unnecessary and should also
> be removed.
> 
> 
> -- 
> H.J.
A changelog entry is here. You cannot remove
sysdeps/x86_64/multiarch/rtld-strlen.S as we cannot now use sse2 in
rtld. I had patch that removed that restriction, when I return back on
it and it will be commited then it could be removed.

2013-03-18  Ondrej Bilka  <neleai@seznam.cz>

        * sysdeps/x86_64/strlen.S: Replace with new SSE2 based
        implementation which is faster on all x86_64 architectures.
        Tested on AMD, Intel Nehalem, SNB, IVB.
        * sysdeps/x86_64/strnlen.S: Likewise.