From: Francesco Fusco <ffusco@redhat.com>
To: Jesse Gross <jesse@nicira.com>
Cc: netdev <netdev@vger.kernel.org>,
"dev@openvswitch.org" <dev@openvswitch.org>,
Daniel Borkmann <dborkman@redhat.com>,
Thomas Graf <tgraf@redhat.com>
Subject: Re: [PATCH net-next v2 2/2] net: ovs: use CRC32 accelerated flow hash if available
Date: Fri, 13 Dec 2013 10:55:23 +0100 [thread overview]
Message-ID: <52AAD98B.7030100@redhat.com> (raw)
In-Reply-To: <CAEP_g=-JBT_XVvwSa4xOwVoTysoL0Z8zJc-ERSHJc96+qrA99Q@mail.gmail.com>
On 12/12/2013 09:20 PM, Jesse Gross wrote:
> Out of curiosity, did you try using crc32q? OVS data structures are
> already aligned to 8 bytes. It would also be interesting to know if a
> parallelized implementation is worthwhile, although my guess is that
> the OVS flow key is not quite long enough.
We did not try with crc32q yet because we had the very same concerns.
In the general case, when the length of the key is not a multiple of 8
bytes, we will have to use the crc32q to process multiple 64 bit
numbers, then process the the rest with a crc32l. My guess is that the
performance benefit won't be that high.
But we will try that out and if the outcome will be positive, we will
submit a follow up patch.
Best,
Francesco
next prev parent reply other threads:[~2013-12-13 9:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-12 15:09 [PATCH net-next v2 0/2] ovs: introduce arch-specific fast hashing improvements Francesco Fusco
2013-12-12 15:09 ` [PATCH net-next v2 2/2] net: ovs: use CRC32 accelerated flow hash if available Francesco Fusco
2013-12-12 20:20 ` Jesse Gross
2013-12-13 9:55 ` Francesco Fusco [this message]
2013-12-13 21:12 ` Jesse Gross
[not found] ` <CAEP_g=-JBT_XVvwSa4xOwVoTysoL0Z8zJc-ERSHJc96+qrA99Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-12-13 10:01 ` David Laight
2013-12-13 14:53 ` Francesco Fusco
2013-12-12 21:12 ` [PATCH net-next v2 0/2] ovs: introduce arch-specific fast hashing improvements David Miller
[not found] ` <1386860946-1621-1-git-send-email-ffusco-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-12-12 15:09 ` [PATCH net-next v2 1/2] lib: introduce arch optimized hash library Francesco Fusco
2013-12-12 17:54 ` Nicolas Dichtel
[not found] ` <52A9F84F.8060500-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
2013-12-12 18:04 ` Daniel Borkmann
2013-12-17 19:28 ` [PATCH net-next v2 0/2] ovs: introduce arch-specific fast hashing improvements David Miller
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