Messages in this thread |  | | Date | Thu, 12 Dec 2013 18:54:23 +0100 | From | Nicolas Dichtel <> | Subject | Re: [PATCH net-next v2 1/2] lib: introduce arch optimized hash library |
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Le 12/12/2013 16:09, Francesco Fusco a écrit : > We introduce a new hashing library that is meant to be used in > the contexts where speed is more important than uniformity of the > hashed values. The hash library leverages architecture specific > implementation to achieve high performance and fall backs to > jhash() for the generic case. > > On Intel-based x86 architectures, the library can exploit the crc32l > instruction, part of the Intel SSE4.2 instruction set, if the > instruction is supported by the processor. This implementation > is twice as fast as the jhash() implementation on an i7 processor. > > Additional architectures, such as Arm64 provide instructions for > accelerating the computation of CRC, so they could be added as well > in follow-up work. > > Signed-off-by: Francesco Fusco <ffusco@redhat.com> > Signed-off-by: Daniel Borkmann <dborkman@redhat.com> > Signed-off-by: Thomas Graf <tgraf@redhat.com> > Cc: linux-kernel@vger.kernel.org > --- > arch/x86/include/asm/hash.h | 7 ++++ > arch/x86/lib/Makefile | 2 +- > arch/x86/lib/hash.c | 88 +++++++++++++++++++++++++++++++++++++++++++++ > include/asm-generic/hash.h | 9 +++++ > include/linux/hash.h | 36 +++++++++++++++++++ > lib/Makefile | 2 +- > lib/hash.c | 38 ++++++++++++++++++++ > 7 files changed, 180 insertions(+), 2 deletions(-) > create mode 100644 arch/x86/include/asm/hash.h > create mode 100644 arch/x86/lib/hash.c > create mode 100644 include/asm-generic/hash.h > create mode 100644 lib/hash.c > > diff --git a/arch/x86/include/asm/hash.h b/arch/x86/include/asm/hash.h > new file mode 100644 > index 0000000..e8c58f8 > --- /dev/null > +++ b/arch/x86/include/asm/hash.h > @@ -0,0 +1,7 @@ > +#ifndef _ASM_X86_HASH_H > +#define _ASM_X86_HASH_H > + > +struct fast_hash_ops; > +extern void setup_arch_fast_hash(struct fast_hash_ops *ops); > + > +#endif /* _ASM_X86_HASH_H */ > diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile > index 992d63b..eabcb6e 100644 > --- a/arch/x86/lib/Makefile > +++ b/arch/x86/lib/Makefile > @@ -24,7 +24,7 @@ lib-$(CONFIG_SMP) += rwlock.o > lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o > lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o > > -obj-y += msr.o msr-reg.o msr-reg-export.o > +obj-y += msr.o msr-reg.o msr-reg-export.o hash.o > > ifeq ($(CONFIG_X86_32),y) > obj-y += atomic64_32.o > diff --git a/arch/x86/lib/hash.c b/arch/x86/lib/hash.c > new file mode 100644 > index 0000000..3056702 > --- /dev/null > +++ b/arch/x86/lib/hash.c > @@ -0,0 +1,88 @@ > +/* > + * Some portions derived from code covered by the following notice: > + * > + * Copyright (c) 2010-2013 Intel Corporation. All rights reserved. > + * All rights reserved. Is it possible to trace that this comes from the DPDK? At least in the commit log, like it was done in the v1.
> + * > + * Redistribution and use in source and binary forms, with or without > + * modification, are permitted provided that the following conditions > + * are met: > + * > + * * Redistributions of source code must retain the above copyright > + * notice, this list of conditions and the following disclaimer. > + * * Redistributions in binary form must reproduce the above copyright > + * notice, this list of conditions and the following disclaimer in > + * the documentation and/or other materials provided with the > + * distribution. > + * * Neither the name of Intel Corporation nor the names of its > + * contributors may be used to endorse or promote products derived > + * from this software without specific prior written permission. > + * > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS > + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT > + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR > + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT > + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, > + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT > + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, > + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY > + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT > + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE > + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. > + */ > + > +#include <linux/hash.h> > + > +#include <asm/processor.h> > +#include <asm/cpufeature.h> > +#include <asm/hash.h> > + > +static inline u32 crc32_u32(u32 crc, u32 val) > +{ > + asm ("crc32l %1,%0\n" : "+r" (crc) : "rm" (val)); I'm not an expert, but is it not possible to use intrisics functions, like it is done in the original code?
Regards, Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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