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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>,
	David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org, therbert@google.com, jhs@mojatatu.com,
	edumazet@google.com, jeffrey.t.kirsher@intel.com,
	rusty@rustcorp.com.au, dborkman@redhat.com, brouer@redhat.com
Subject: Re: [PATCH 0/2] Get rid of ndo_xmit_flush
Date: Wed, 27 Aug 2014 15:56:51 +0200	[thread overview]
Message-ID: <20140827155651.04fe49d0@redhat.com> (raw)
In-Reply-To: <1409145838.3173.41.camel@edumazet-glaptop2.roam.corp.google.com>

On Wed, 27 Aug 2014 06:23:58 -0700
Eric Dumazet <eric.dumazet@gmail.com> wrote:

> I am afraid Jesper tests are not complete to truly have a picture of the
> extra costs, because he made sure no false sharing was possible (A
> single cpu does everything and keeps skb in its cache)

I fully agree. My tests a very artificial benchmarks only for the
optimal case.

I do worry a bit, if writing skb->xmit_more in a more cache cold
scenarios could hurt us (as that cacheline seems to be read mostly),
but this is not a problem right now because it will always be cache
hot, as we always clear the entire SKB in alloc.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Sr. Network Kernel Developer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

  reply	other threads:[~2014-08-27 13:57 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-25 23:34 [PATCH 0/2] Get rid of ndo_xmit_flush David Miller
2014-08-26  6:28 ` Jesper Dangaard Brouer
2014-08-26 10:13   ` Jesper Dangaard Brouer
2014-08-26 12:52     ` Jesper Dangaard Brouer
2014-08-26 16:43       ` Alexander Duyck
2014-08-27  7:48         ` Jesper Dangaard Brouer
2014-08-27  8:37           ` Jesper Dangaard Brouer
2014-08-26 14:40     ` Jamal Hadi Salim
2014-09-01  0:37     ` Rusty Russell
2014-08-27 12:19 ` Jesper Dangaard Brouer
2014-08-27 20:43   ` David Miller
2014-08-27 12:31 ` Hannes Frederic Sowa
2014-08-27 13:23   ` Eric Dumazet
2014-08-27 13:56     ` Jesper Dangaard Brouer [this message]
2014-08-27 14:09       ` Eric Dumazet
2014-08-27 20:48       ` David Miller
2014-08-27 20:46     ` David Miller
2014-08-27 20:45   ` David Miller
2014-08-28  1:42     ` Hannes Frederic Sowa
2014-08-30  3:22       ` David Miller
2014-08-30 10:23         ` Jesper Dangaard Brouer
2014-09-01 20:05         ` Hannes Frederic Sowa
2014-09-01 21:56           ` David Miller
2014-09-01 22:31             ` Hannes Frederic Sowa
2014-09-01 22:35               ` David Miller
2014-08-27 18:28 ` Cong Wang
2014-08-27 19:31   ` Tom Herbert
2014-08-27 20:53     ` David Miller
2014-08-27 20:51   ` David Miller

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