From: Scott Wood <scottwood@freescale.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
<linux-kernel@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>,
<netdev@vger.kernel.org>
Subject: Re: [PATCH 8/9] powerpc: simplify csum_add(a, b) in case a or b is constant 0
Date: Thu, 22 Oct 2015 22:33:27 -0500 [thread overview]
Message-ID: <1445571207.701.152.camel@freescale.com> (raw)
In-Reply-To: <5549ecca2c921f34d076c47b5e2a91a3e78b20a7.1442876807.git.christophe.leroy@c-s.fr>
On Tue, 2015-09-22 at 16:34 +0200, Christophe Leroy wrote:
> Simplify csum_add(a, b) in case a or b is constant 0
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/include/asm/checksum.h | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/checksum.h
> b/arch/powerpc/include/asm/checksum.h
> index 56deea8..f8a9704 100644
> --- a/arch/powerpc/include/asm/checksum.h
> +++ b/arch/powerpc/include/asm/checksum.h
> @@ -119,7 +119,13 @@ static inline __wsum csum_add(__wsum csum, __wsum
> addend)
> {
> #ifdef __powerpc64__
> u64 res = (__force u64)csum;
> +#endif
> + if (__builtin_constant_p(csum) && csum == 0)
> + return addend;
> + if (__builtin_constant_p(addend) && addend == 0)
> + return csum;
>
> +#ifdef __powerpc64__
> res += (__force u64)addend;
> return (__force __wsum)((u32)res + (res >> 32));
> #else
How often does this happen?
-Scott
next prev parent reply other threads:[~2015-10-23 3:33 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-22 14:34 [PATCH 0/9] powerpc32: set of optimisation of network checksum functions Christophe Leroy
2015-09-22 14:34 ` [PATCH 1/9] powerpc: unexport csum_tcpudp_magic Christophe Leroy
2015-09-22 14:34 ` [PATCH 2/9] powerpc: mark xer clobbered in csum_add() Christophe Leroy
2015-09-22 14:34 ` [PATCH 3/9] powerpc32: checksum_wrappers_64 becomes checksum_wrappers Christophe Leroy
2015-10-23 3:26 ` Scott Wood
2015-10-28 11:11 ` Anton Blanchard
2015-09-22 14:34 ` [PATCH 4/9] powerpc: inline ip_fast_csum() Christophe Leroy
2015-09-23 5:43 ` Denis Kirjanov
2016-02-29 7:25 ` Christophe Leroy
2016-03-05 3:50 ` [4/9] " Scott Wood
2015-09-22 14:34 ` [PATCH 5/9] powerpc32: rewrite csum_partial_copy_generic() based on copy_tofrom_user() Christophe Leroy
2015-09-22 14:34 ` [PATCH 6/9] powerpc32: optimise a few instructions in csum_partial() Christophe Leroy
2015-10-23 3:30 ` Scott Wood
2016-02-29 12:53 ` Christophe Leroy
2015-09-22 14:34 ` [PATCH 7/9] powerpc32: optimise csum_partial() loop Christophe Leroy
2015-09-22 14:34 ` [PATCH 8/9] powerpc: simplify csum_add(a, b) in case a or b is constant 0 Christophe Leroy
2015-10-23 3:33 ` Scott Wood [this message]
2016-02-29 7:26 ` Christophe Leroy
2015-09-22 14:34 ` [PATCH 9/9] powerpc: optimise csum_partial() call when len is constant Christophe Leroy
2015-10-23 3:32 ` Scott Wood
2016-03-05 5:29 ` [9/9] " Scott Wood
2015-09-23 22:38 ` [PATCH 0/9] powerpc32: set of optimisation of network checksum functions David Miller
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