From: Palmer Dabbelt <palmer@dabbelt.com>
To: mcroce@linux.microsoft.com
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org,
Paul Walmsley <paul.walmsley@sifive.com>,
aou@eecs.berkeley.edu, Atish Patra <Atish.Patra@wdc.com>,
kernel@esmil.dk, akira.tsukamoto@gmail.com, drew@beagleboard.org,
bmeng.cn@gmail.com, David.Laight@aculab.com, guoren@kernel.org,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v4 0/3] riscv: optimized mem* functions
Date: Thu, 07 Oct 2021 18:26:44 -0700 (PDT) [thread overview]
Message-ID: <mhng-1ef62a9c-06e5-43cf-a4ec-8c18111e79d3@palmerdabbelt-glaptop> (raw)
In-Reply-To: <20210919192104.98592-1-mcroce@linux.microsoft.com>
On Sun, 19 Sep 2021 12:21:01 PDT (-0700), mcroce@linux.microsoft.com wrote:
> From: Matteo Croce <mcroce@microsoft.com>
>
> Replace the assembly mem{cpy,move,set} with C equivalent.
>
> Try to access RAM with the largest bit width possible, but without
> doing unaligned accesses.
>
> A further improvement could be to use multiple read and writes as the
> assembly version was trying to do.
>
> Tested on a BeagleV Starlight with a SiFive U74 core, where the
> improvement is noticeable.
>
> v3 -> v4:
> - incorporate changes from proposed generic version:
> https://lore.kernel.org/lkml/20210617152754.17960-1-mcroce@linux.microsoft.com/
>
> v2 -> v3:
> - alias mem* to __mem* and not viceversa
> - use __alias instead of a tail call
>
> v1 -> v2:
> - reduce the threshold from 64 to 16 bytes
> - fix KASAN build
> - optimize memset
>
> Matteo Croce (3):
> riscv: optimized memcpy
> riscv: optimized memmove
> riscv: optimized memset
>
> arch/riscv/include/asm/string.h | 18 ++--
> arch/riscv/kernel/Makefile | 1 -
> arch/riscv/kernel/riscv_ksyms.c | 17 ----
> arch/riscv/lib/Makefile | 4 +-
> arch/riscv/lib/memcpy.S | 108 ----------------------
> arch/riscv/lib/memmove.S | 64 -------------
> arch/riscv/lib/memset.S | 113 -----------------------
> arch/riscv/lib/string.c | 154 ++++++++++++++++++++++++++++++++
> 8 files changed, 164 insertions(+), 315 deletions(-)
> delete mode 100644 arch/riscv/kernel/riscv_ksyms.c
> delete mode 100644 arch/riscv/lib/memcpy.S
> delete mode 100644 arch/riscv/lib/memmove.S
> delete mode 100644 arch/riscv/lib/memset.S
> create mode 100644 arch/riscv/lib/string.c
Thanks. These generally look good, but they're failing to build for me.
I'm getting errors along the lines of
arch/riscv/lib/string.c:89:7: error: inlining failed in call to ‘always_inline’ ‘memcpy’: function body can be overwritten at link time
89 | void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy); | ^~~~~~
arch/riscv/lib/string.c:99:10: note: called from here
99 | return memcpy(dest, src, count);
| ^~~~~~~~~~~~~~~~~~~~~~~~
I'm still a bit behind on email so I'm going to keep going through
patches, but if there's no v5 by the time I get back here then I'll take
a look.
next prev parent reply other threads:[~2021-10-08 1:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-19 19:21 [PATCH v4 0/3] riscv: optimized mem* functions Matteo Croce
2021-09-19 19:21 ` [PATCH v4 1/3] riscv: optimized memcpy Matteo Croce
2021-09-19 19:21 ` [PATCH v4 2/3] riscv: optimized memmove Matteo Croce
2021-09-19 22:05 ` kernel test robot
2021-09-27 10:48 ` Matteo Croce
2021-09-29 17:04 ` Emil Renner Berthing
2021-09-19 19:21 ` [PATCH v4 3/3] riscv: optimized memset Matteo Croce
2021-09-19 22:00 ` [PATCH v4 0/3] riscv: optimized mem* functions Matteo Croce
2021-10-08 1:26 ` Palmer Dabbelt [this message]
2021-10-08 1:39 ` Matteo Croce
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