Re: [PATCH v1 1/2] x86: Move mem{p}{mov|cpy}_{chk_}erms to its own file

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

On Wed, Jun 29, 2022 at 1:03 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Wed, Jun 29, 2022 at 12:59 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > On Wed, Jun 29, 2022 at 12:48 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > >
> > > On Wed, Jun 29, 2022 at 12:46 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > > >
> > > > On Wed, Jun 29, 2022 at 12:34 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > > > >
> > > > > On Wed, Jun 29, 2022 at 12:32 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > > > > >
> > > > > > On Tue, Jun 28, 2022 at 8:28 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > > > > > >
> > > > > > > The primary memmove_{impl}_unaligned_erms implementations don't
> > > > > > > interact with this function. Putting them in same file both
> > > > > > > wastes space and unnecessarily bloats a hot code section.
> > > > > > > ---
> > > > > > >  sysdeps/x86_64/multiarch/memmove-erms.S       | 53 +++++++++++++++++++
> > > > > > >  .../multiarch/memmove-vec-unaligned-erms.S    | 50 -----------------
> > > > > > >  2 files changed, 53 insertions(+), 50 deletions(-)
> > > > > > >  create mode 100644 sysdeps/x86_64/multiarch/memmove-erms.S
> > > > > > >
> > > > > > > diff --git a/sysdeps/x86_64/multiarch/memmove-erms.S b/sysdeps/x86_64/multiarch/memmove-erms.S
> > > > > > > new file mode 100644
> > > > > > > index 0000000000..d98d21644b
> > > > > > > --- /dev/null
> > > > > > > +++ b/sysdeps/x86_64/multiarch/memmove-erms.S
> > > > > > > @@ -0,0 +1,53 @@
> > > > > > > +#include <sysdep.h>
> > > > > > > +
> > > > > > > +#if defined USE_MULTIARCH && IS_IN (libc)
> > > > > > > +       .text
> > > > > > > +ENTRY (__mempcpy_chk_erms)
> > > > > > > +       cmp     %RDX_LP, %RCX_LP
> > > > > > > +       jb      HIDDEN_JUMPTARGET (__chk_fail)
> > > > > > > +END (__mempcpy_chk_erms)
> > > > > > > +
> > > > > > > +/* Only used to measure performance of REP MOVSB.  */
> > > > > > > +ENTRY (__mempcpy_erms)
> > > > > > > +       mov     %RDI_LP, %RAX_LP
> > > > > > > +       /* Skip zero length.  */
> > > > > > > +       test    %RDX_LP, %RDX_LP
> > > > > > > +       jz      2f
> > > > > > > +       add     %RDX_LP, %RAX_LP
> > > > > > > +       jmp     L(start_movsb)
> > > > > > > +END (__mempcpy_erms)
> > > > > > > +
> > > > > > > +ENTRY (__memmove_chk_erms)
> > > > > > > +       cmp     %RDX_LP, %RCX_LP
> > > > > > > +       jb      HIDDEN_JUMPTARGET (__chk_fail)
> > > > > > > +END (__memmove_chk_erms)
> > > > > > > +
> > > > > > > +ENTRY (__memmove_erms)
> > > > > > > +       movq    %rdi, %rax
> > > > > > > +       /* Skip zero length.  */
> > > > > > > +       test    %RDX_LP, %RDX_LP
> > > > > > > +       jz      2f
> > > > > > > +L(start_movsb):
> > > > > > > +       mov     %RDX_LP, %RCX_LP
> > > > > > > +       cmp     %RSI_LP, %RDI_LP
> > > > > > > +       jb      1f
> > > > > > > +       /* Source == destination is less common.  */
> > > > > > > +       je      2f
> > > > > > > +       lea     (%rsi,%rcx), %RDX_LP
> > > > > > > +       cmp     %RDX_LP, %RDI_LP
> > > > > > > +       jb      L(movsb_backward)
> > > > > > > +1:
> > > > > > > +       rep movsb
> > > > > > > +2:
> > > > > > > +       ret
> > > > > > > +L(movsb_backward):
> > > > > > > +       leaq    -1(%rdi,%rcx), %rdi
> > > > > > > +       leaq    -1(%rsi,%rcx), %rsi
> > > > > > > +       std
> > > > > > > +       rep movsb
> > > > > > > +       cld
> > > > > > > +       ret
> > > > > > > +END (__memmove_erms)
> > > > > > > +strong_alias (__memmove_erms, __memcpy_erms)
> > > > > > > +strong_alias (__memmove_chk_erms, __memcpy_chk_erms)
> > > > > > > +#endif
> > > > > > > diff --git a/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
> > > > > > > index d1518b8bab..04747133b7 100644
> > > > > > > --- a/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
> > > > > > > +++ b/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
> > > > > > > @@ -239,56 +239,6 @@ L(start):
> > > > > > >  #endif
> > > > > > >  #if defined USE_MULTIARCH && IS_IN (libc)
> > > > > > >  END (MEMMOVE_SYMBOL (__memmove, unaligned))
> > > > > > > -# if VEC_SIZE == 16
> > > > > > > -ENTRY (__mempcpy_chk_erms)
> > > > > > > -       cmp     %RDX_LP, %RCX_LP
> > > > > > > -       jb      HIDDEN_JUMPTARGET (__chk_fail)
> > > > > > > -END (__mempcpy_chk_erms)
> > > > > > > -
> > > > > > > -/* Only used to measure performance of REP MOVSB.  */
> > > > > > > -ENTRY (__mempcpy_erms)
> > > > > > > -       mov     %RDI_LP, %RAX_LP
> > > > > > > -       /* Skip zero length.  */
> > > > > > > -       test    %RDX_LP, %RDX_LP
> > > > > > > -       jz      2f
> > > > > > > -       add     %RDX_LP, %RAX_LP
> > > > > > > -       jmp     L(start_movsb)
> > > > > > > -END (__mempcpy_erms)
> > > > > > > -
> > > > > > > -ENTRY (__memmove_chk_erms)
> > > > > > > -       cmp     %RDX_LP, %RCX_LP
> > > > > > > -       jb      HIDDEN_JUMPTARGET (__chk_fail)
> > > > > > > -END (__memmove_chk_erms)
> > > > > > > -
> > > > > > > -ENTRY (__memmove_erms)
> > > > > > > -       movq    %rdi, %rax
> > > > > > > -       /* Skip zero length.  */
> > > > > > > -       test    %RDX_LP, %RDX_LP
> > > > > > > -       jz      2f
> > > > > > > -L(start_movsb):
> > > > > > > -       mov     %RDX_LP, %RCX_LP
> > > > > > > -       cmp     %RSI_LP, %RDI_LP
> > > > > > > -       jb      1f
> > > > > > > -       /* Source == destination is less common.  */
> > > > > > > -       je      2f
> > > > > > > -       lea     (%rsi,%rcx), %RDX_LP
> > > > > > > -       cmp     %RDX_LP, %RDI_LP
> > > > > > > -       jb      L(movsb_backward)
> > > > > > > -1:
> > > > > > > -       rep movsb
> > > > > > > -2:
> > > > > > > -       ret
> > > > > > > -L(movsb_backward):
> > > > > > > -       leaq    -1(%rdi,%rcx), %rdi
> > > > > > > -       leaq    -1(%rsi,%rcx), %rsi
> > > > > > > -       std
> > > > > > > -       rep movsb
> > > > > > > -       cld
> > > > > > > -       ret
> > > > > > > -END (__memmove_erms)
> > > > > > > -strong_alias (__memmove_erms, __memcpy_erms)
> > > > > > > -strong_alias (__memmove_chk_erms, __memcpy_chk_erms)
> > > > > > > -# endif
> > > > > > >
> > > > > > >  # ifdef SHARED
> > > > > > >  ENTRY (MEMMOVE_CHK_SYMBOL (__mempcpy_chk, unaligned_erms))
> > > > > > > --
> > > > > > > 2.34.1
> > > > > > >
> > > > > >
> > > > > > Please make a standalone patch.
> > > > >
> > > > > The memmove isa raising change has a dependency on it hence the series.
> > > > > Submit this first then rebsubmit memmove? Same for memset-erms /
> > > > > memset-isa raising?
> > > >
> > > > Yes.  Moving the erms version to a separate file should be standalone.
> > > > Each patch should build.
> > >
> > > The reason it doesn't is that the isa raising for memmove-vec...
> > > would require handling the memmove_erms case for it to build
> > > otherwise ISA V3/V4 would leave memmove_erms
> > > as undefined symbols in the multiarch build.
> >
> > The first patch in your patch set isn't standalone since Makefile
> > change is in the second patch.
>
> Err I think there is a misunderstanding.
>
> I am going to fixup to make the memmove_erms / memset_erms
> changes standalone. My point is the following ISA raising patches
> are dependent on the respective erms functions being moved.
>
> Hences its a series.

A series is OK.

> >
> > >
> > >
> > > > You should combine 2 memset-erms changes
> > > > in 2 memset patches into a single patch.
> > > ?
> > >
> >
> > The first patch moves memset-erms to the file end
> > and the second patch moves it to another file.
> >
> > --
> > H.J.



-- 
H.J.