linux-kernel - Re: [PATCH v2 2/2] crypto, x86: SSSE3 based SHA1 implementation for x86-64

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 11 Aug 2011 10:50:49 -0400
From:	Andy Lutomirski <luto@....EDU>
To:	Herbert Xu <herbert@...dor.hengli.com.au>
CC:	Mathias Krause <minipli@...glemail.com>,
	"David S. Miller" <davem@...emloft.net>,
	linux-crypto@...r.kernel.org,
	Maxim Locktyukhin <maxim.locktyukhin@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] crypto, x86: SSSE3 based SHA1 implementation for
 x86-64

On 08/04/2011 02:44 AM, Herbert Xu wrote:
> On Sun, Jul 24, 2011 at 07:53:14PM +0200, Mathias Krause wrote:
>>
>> With this algorithm I was able to increase the throughput of a single
>> IPsec link from 344 Mbit/s to 464 Mbit/s on a Core 2 Quad CPU using
>> the SSSE3 variant -- a speedup of +34.8%.
>
> Were you testing this on the transmit side or the receive side?
>
> As the IPsec receive code path usually runs in a softirq context,
> does this code have any effect there at all?
>
> This is pretty similar to the situation with the Intel AES code.
> Over there they solved it by using the asynchronous interface and
> deferring the processing to a work queue.

I have vague plans to clean up extended state handling and make 
kernel_fpu_begin work efficiently from any context.  (i.e. the first 
kernel_fpu_begin after a context switch could take up to ~60 ns on Sandy 
Bridge, but further calls to kernel_fpu_begin would be a single branch.)

The current code that handles context switches when user code is using 
extended state is terrible and will almost certainly become faster in 
the near future.

Hopefully I'll have patches for 3.2 or 3.3.

IOW, please don't introduce another thing like the fpu crypto module 
quite yet unless there's a good reason.  I'm looking forward to deleting 
the fpu module entirely.

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/