[PATCH v5 02/17] Parameterize OP_T_THRES from memcopy.h
Carlos O'Donell
carlos@redhat.com
Tue Sep 20 10:49:38 GMT 2022
On Mon, Sep 19, 2022 at 04:59:05PM -0300, Adhemerval Zanella via Libc-alpha wrote:
> From: Richard Henderson <rth@twiddle.net>
>
> It moves OP_T_THRES out of memcopy.h to its own header and adjust
> each architecture that redefines it.
>
> Checked with a build and check with run-built-tests=no for all major
> Linux ABIs.
This is a generic refactor which I think can go in regardless.
We can always reorganize again if we end up wtih too many split headers
and want to talk about unrolling in different contexts.
LGTM.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> string/memcmp.c | 3 ---
> sysdeps/generic/memcopy.h | 4 +---
> sysdeps/generic/string-opthr.h | 25 ++++++++++++++++++++++
> sysdeps/i386/memcopy.h | 3 ---
> sysdeps/i386/string-opthr.h | 25 ++++++++++++++++++++++
> sysdeps/m68k/memcopy.h | 3 ---
> sysdeps/powerpc/powerpc32/power4/memcopy.h | 5 -----
> 7 files changed, 51 insertions(+), 17 deletions(-)
> create mode 100644 sysdeps/generic/string-opthr.h
> create mode 100644 sysdeps/i386/string-opthr.h
>
> diff --git a/string/memcmp.c b/string/memcmp.c
> index 6a9ceb8ac3..7c4606c2d0 100644
> --- a/string/memcmp.c
> +++ b/string/memcmp.c
> @@ -48,9 +48,6 @@
> and store. Must be an unsigned type. */
> # define OPSIZ (sizeof (op_t))
>
> -/* Threshold value for when to enter the unrolled loops. */
> -# define OP_T_THRES 16
> -
> /* Type to use for unaligned operations. */
> typedef unsigned char byte;
>
> diff --git a/sysdeps/generic/memcopy.h b/sysdeps/generic/memcopy.h
> index efe5f2475d..a6baa4dfbb 100644
> --- a/sysdeps/generic/memcopy.h
> +++ b/sysdeps/generic/memcopy.h
> @@ -57,6 +57,7 @@
>
> /* Type to use for aligned memory operations. */
> #include <string-optype.h>
> +#include <string-opthr.h>
> #define OPSIZ (sizeof (op_t))
>
> /* Type to use for unaligned operations. */
> @@ -188,9 +189,6 @@ extern void _wordcopy_bwd_dest_aligned (long int, long int, size_t)
>
> #endif
>
> -/* Threshold value for when to enter the unrolled loops. */
> -#define OP_T_THRES 16
> -
> /* Set to 1 if memcpy is safe to use for forward-copying memmove with
> overlapping addresses. This is 0 by default because memcpy implementations
> are generally not safe for overlapping addresses. */
> diff --git a/sysdeps/generic/string-opthr.h b/sysdeps/generic/string-opthr.h
> new file mode 100644
> index 0000000000..eabd9fd669
> --- /dev/null
> +++ b/sysdeps/generic/string-opthr.h
> @@ -0,0 +1,25 @@
> +/* Define a threshold for word access. Generic version.
> + Copyright (C) 2022 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef _STRING_OPTHR_H
> +#define _STRING_OPTHR_H 1
> +
> +/* Threshold value for when to enter the unrolled loops. */
> +#define OP_T_THRES 16
> +
> +#endif /* string-opthr.h */
> diff --git a/sysdeps/i386/memcopy.h b/sysdeps/i386/memcopy.h
> index 8cbf182096..66f5665f82 100644
> --- a/sysdeps/i386/memcopy.h
> +++ b/sysdeps/i386/memcopy.h
> @@ -18,9 +18,6 @@
>
> #include <sysdeps/generic/memcopy.h>
>
> -#undef OP_T_THRES
> -#define OP_T_THRES 8
> -
> #undef BYTE_COPY_FWD
> #define BYTE_COPY_FWD(dst_bp, src_bp, nbytes) \
> do { \
> diff --git a/sysdeps/i386/string-opthr.h b/sysdeps/i386/string-opthr.h
> new file mode 100644
> index 0000000000..ed3e4b2ddb
> --- /dev/null
> +++ b/sysdeps/i386/string-opthr.h
> @@ -0,0 +1,25 @@
> +/* Define a threshold for word access. i386 version.
> + Copyright (C) 2018 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef I386_STRING_OPTHR_H
> +#define I386_STRING_OPTHR_H 1
> +
> +/* Threshold value for when to enter the unrolled loops. */
> +#define OP_T_THRES 8
> +
> +#endif /* I386_STRING_OPTHR_H */
> diff --git a/sysdeps/m68k/memcopy.h b/sysdeps/m68k/memcopy.h
> index cf147f2c4a..3777baac21 100644
> --- a/sysdeps/m68k/memcopy.h
> +++ b/sysdeps/m68k/memcopy.h
> @@ -20,9 +20,6 @@
>
> #if defined(__mc68020__) || defined(mc68020)
>
> -#undef OP_T_THRES
> -#define OP_T_THRES 16
> -
> /* WORD_COPY_FWD and WORD_COPY_BWD are not symmetric on the 68020,
> because of its weird instruction overlap characteristics. */
>
> diff --git a/sysdeps/powerpc/powerpc32/power4/memcopy.h b/sysdeps/powerpc/powerpc32/power4/memcopy.h
> index a98f6662d8..d27caa2277 100644
> --- a/sysdeps/powerpc/powerpc32/power4/memcopy.h
> +++ b/sysdeps/powerpc/powerpc32/power4/memcopy.h
> @@ -50,11 +50,6 @@
> [I fail to understand. I feel stupid. --roland]
> */
>
> -
> -/* Threshold value for when to enter the unrolled loops. */
> -#undef OP_T_THRES
> -#define OP_T_THRES 16
> -
> /* Copy exactly NBYTES bytes from SRC_BP to DST_BP,
> without any assumptions about alignment of the pointers. */
> #undef BYTE_COPY_FWD
> --
> 2.34.1
>
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