DPDK patches and discussions
 help / color / mirror / Atom feed
From: Jim Thompson <jim@netgate.com>
To: Matthew Hall <mhall@mhcomputing.net>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] Broken RSS hash computation on Intel 82574L
Date: Tue, 1 Sep 2015 10:19:23 -0500	[thread overview]
Message-ID: <8B6A7DA3-93AF-4DD2-8857-2DB548A45B8D@netgate.com> (raw)
In-Reply-To: <20150901144726.GA30421@mhcomputing.net>


> On Sep 1, 2015, at 9:47 AM, Matthew Hall <mhall@mhcomputing.net> wrote:
> 
> On Tue, Sep 01, 2015 at 04:37:18PM +0200, Martin Drašar wrote:
>> Dne 1.9.2015 v 15:45 De Lara Guarch, Pablo napsal(a):
>>> 82574L NIC uses em PMD, which does not support more than 1 queue.
>>> Therefore RSS is disabled in the NIC and then you cannot have RSS hashes.
>>> 
>>> Thanks,
>>> Pablo
>> 
>> Hi Pablo,
>> 
>> that is an interesting information. I read the rationale in em_ethdev.c
>> and I was wondering, what would have to be done to enable RSS hash
>> computation on that card. I can live with just one RX queue, but hashes
>> would help me a lot. The computer which is using those NICs is not that
>> powerful and every bit of offloaded computation counts...
>> 
>> Thanks,
>> Martin
> 
> RSS calculations are used to direct packets across multiple RX queues. With 
> only one RX queue it cannot possibly increase performance by enabling it.

Well, there are other things you could use that hw-provided hash for…

(but point-taken)

      parent reply	other threads:[~2015-09-01 15:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-31 12:15 Martin Drašar
2015-09-01 13:45 ` De Lara Guarch, Pablo
2015-09-01 14:37   ` Martin Drašar
2015-09-01 14:47     ` Matthew Hall
2015-09-01 14:50       ` Avi Kivity
2015-09-01 15:00         ` Martin Drašar
2015-09-01 15:19       ` Jim Thompson [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=8B6A7DA3-93AF-4DD2-8857-2DB548A45B8D@netgate.com \
    --to=jim@netgate.com \
    --cc=dev@dpdk.org \
    --cc=mhall@mhcomputing.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).