From: Matteo Croce <mcroce@linux.microsoft.com> To: linux-kernel@vger.kernel.org, Nick Kossifidis <mick@ics.forth.gr>, Guo Ren <guoren@kernel.org>, Christoph Hellwig <hch@infradead.org>, David Laight <David.Laight@aculab.com>, Palmer Dabbelt <palmer@dabbelt.com>, Emil Renner Berthing <kernel@esmil.dk>, Drew Fustini <drew@beagleboard.org> Cc: linux-arch@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Nick Desaulniers <ndesaulniers@google.com>, linux-riscv@lists.infradead.org Subject: [PATCH v2 0/3] lib/string: optimized mem* functions Date: Fri, 2 Jul 2021 14:31:50 +0200 [thread overview] Message-ID: <20210702123153.14093-1-mcroce@linux.microsoft.com> (raw) From: Matteo Croce <mcroce@microsoft.com> Rewrite the generic mem{cpy,move,set} so that memory is accessed with the widest size possible, but without doing unaligned accesses. This was originally posted as C string functions for RISC-V[1], but as there was no specific RISC-V code, it was proposed for the generic lib/string.c implementation. Tested on RISC-V and on x86_64 by undefining __HAVE_ARCH_MEM{CPY,SET,MOVE} and HAVE_EFFICIENT_UNALIGNED_ACCESS. These are the performances of memcpy() and memset() of a RISC-V machine on a 32 mbyte buffer: memcpy: original aligned: 75 Mb/s original unaligned: 75 Mb/s new aligned: 114 Mb/s new unaligned: 107 Mb/s memset: original aligned: 140 Mb/s original unaligned: 140 Mb/s new aligned: 241 Mb/s new unaligned: 241 Mb/s The size increase is negligible: $ scripts/bloat-o-meter vmlinux.orig vmlinux add/remove: 0/0 grow/shrink: 4/1 up/down: 427/-6 (421) Function old new delta memcpy 29 351 +322 memset 29 117 +88 strlcat 68 78 +10 strlcpy 50 57 +7 memmove 56 50 -6 Total: Before=8556964, After=8557385, chg +0.00% These functions will be used for RISC-V initially. [1] https://lore.kernel.org/linux-riscv/20210617152754.17960-1-mcroce@linux.microsoft.com/ Matteo Croce (3): lib/string: optimized memcpy lib/string: optimized memmove lib/string: optimized memset lib/string.c | 130 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 113 insertions(+), 17 deletions(-) -- 2.31.1
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From: Matteo Croce <mcroce@linux.microsoft.com> To: linux-kernel@vger.kernel.org, Nick Kossifidis <mick@ics.forth.gr>, Guo Ren <guoren@kernel.org>, Christoph Hellwig <hch@infradead.org>, David Laight <David.Laight@aculab.com>, Palmer Dabbelt <palmer@dabbelt.com>, Emil Renner Berthing <kernel@esmil.dk>, Drew Fustini <drew@beagleboard.org> Cc: linux-arch@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Nick Desaulniers <ndesaulniers@google.com>, linux-riscv@lists.infradead.org Subject: [PATCH v2 0/3] lib/string: optimized mem* functions Date: Fri, 2 Jul 2021 14:31:50 +0200 [thread overview] Message-ID: <20210702123153.14093-1-mcroce@linux.microsoft.com> (raw) From: Matteo Croce <mcroce@microsoft.com> Rewrite the generic mem{cpy,move,set} so that memory is accessed with the widest size possible, but without doing unaligned accesses. This was originally posted as C string functions for RISC-V[1], but as there was no specific RISC-V code, it was proposed for the generic lib/string.c implementation. Tested on RISC-V and on x86_64 by undefining __HAVE_ARCH_MEM{CPY,SET,MOVE} and HAVE_EFFICIENT_UNALIGNED_ACCESS. These are the performances of memcpy() and memset() of a RISC-V machine on a 32 mbyte buffer: memcpy: original aligned: 75 Mb/s original unaligned: 75 Mb/s new aligned: 114 Mb/s new unaligned: 107 Mb/s memset: original aligned: 140 Mb/s original unaligned: 140 Mb/s new aligned: 241 Mb/s new unaligned: 241 Mb/s The size increase is negligible: $ scripts/bloat-o-meter vmlinux.orig vmlinux add/remove: 0/0 grow/shrink: 4/1 up/down: 427/-6 (421) Function old new delta memcpy 29 351 +322 memset 29 117 +88 strlcat 68 78 +10 strlcpy 50 57 +7 memmove 56 50 -6 Total: Before=8556964, After=8557385, chg +0.00% These functions will be used for RISC-V initially. [1] https://lore.kernel.org/linux-riscv/20210617152754.17960-1-mcroce@linux.microsoft.com/ Matteo Croce (3): lib/string: optimized memcpy lib/string: optimized memmove lib/string: optimized memset lib/string.c | 130 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 113 insertions(+), 17 deletions(-) -- 2.31.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next reply other threads:[~2021-07-02 12:32 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-02 12:31 Matteo Croce [this message] 2021-07-02 12:31 ` [PATCH v2 0/3] lib/string: optimized mem* functions Matteo Croce 2021-07-02 12:31 ` [PATCH v2 1/3] lib/string: optimized memcpy Matteo Croce 2021-07-02 12:31 ` Matteo Croce 2021-07-02 14:37 ` Ben Dooks 2021-07-02 14:37 ` Ben Dooks 2021-07-02 14:44 ` Matteo Croce 2021-07-02 14:44 ` Matteo Croce 2021-07-02 12:31 ` [PATCH v2 2/3] lib/string: optimized memmove Matteo Croce 2021-07-02 12:31 ` Matteo Croce 2021-07-02 12:31 ` [PATCH v2 3/3] lib/string: optimized memset Matteo Croce 2021-07-02 12:31 ` Matteo Croce 2021-07-10 21:31 ` [PATCH v2 0/3] lib/string: optimized mem* functions Andrew Morton 2021-07-10 21:31 ` Andrew Morton 2021-07-10 23:07 ` Matteo Croce 2021-07-10 23:07 ` Matteo Croce 2021-07-12 8:15 ` David Laight 2021-07-12 8:15 ` David Laight
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