From: Alexey Dobriyan <adobriyan@gmail.com>
To: Steffen Klassert <steffen.klassert@secunet.com>
Cc: "herbert@gondor.apana.org.au" <herbert@gondor.apana.org.au>,
"davem@davemloft.net" <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
David Laight <David.Laight@aculab.com>
Subject: Re: [PATCH v2] xfrm: branchless addr4_match() on 64-bit
Date: Mon, 27 Mar 2017 16:11:32 +0300 [thread overview]
Message-ID: <CACVxJT9NJtqpteJ5hVX8FnBYo00_-NokuB2zgq_tuK2b_qA51A@mail.gmail.com> (raw)
In-Reply-To: <20170327103719.GI23004@secunet.com>
On Mon, Mar 27, 2017 at 1:37 PM, Steffen Klassert
<steffen.klassert@secunet.com> wrote:
> On Sat, Mar 25, 2017 at 07:41:17PM +0300, Alexey Dobriyan wrote:
>> After (no branches):
>>
>> mov r8d,0x20
>> mov rdx,0xffffffffffffffff
>> mov esi,DWORD PTR [rsi+0x2c]
>> mov ecx,r8d
>> sub cl,BYTE PTR [rdi+0x2a]
>> xor esi,DWORD PTR [rbx]
>> mov rdi,rdx
>> xor eax,eax
>> shl rdi,cl
>> bswap edi
>>
>> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
>
> Also applied to ipsec-next, thanks for the patches Alexey!
Speaking of optimizations.
1) All those ntohl() invocations inside hashes are likely
unnecessary (hashing is hashing after all).
2) I din't look closely but it can be further optimized by storing
32 - prefixlen (or 128 - prefixlen) but I don't know if you'll accept
such horror. :-)
prev parent reply other threads:[~2017-03-27 13:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-23 23:32 [PATCH] xfrm: branchless addr4_match() on 64-bit Alexey Dobriyan
2017-03-24 17:16 ` David Laight
2017-03-25 16:37 ` Alexey Dobriyan
2017-03-25 16:41 ` [PATCH v2] " Alexey Dobriyan
2017-03-27 10:37 ` Steffen Klassert
2017-03-27 13:11 ` Alexey Dobriyan [this message]
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