Re: [PATCH] Using Intel CRC32 instruction to accelerate CRC32c algorithm by new crypto API.

From: Herbert Xu
Date: Mon Aug 04 2008 - 10:54:57 EST


On Mon, Aug 04, 2008 at 03:49:01PM +0100, David Woodhouse wrote:
>
> And even for people who don't care about that, it doesn't look
> particularly good. It looks like btrfs would need either to keep setting
> up a crypto context and then tearing it down, or have a pool of
> long-standing contexts and do some kind of locking on them -- neither of
> which seem particularly optimal compared with just calling into
> libcrc32c.

No you don't have to set things up every time you use crc32c.
The crypto interface lets you have a single tfm that can be
used by multiple users simultaneously. For ahash algorithms
all the state is stored in the request which can stay on the
stack.

Cheers,
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