From: David Miller <davem@davemloft.net>
To: brouer@redhat.com
Cc: netdev@vger.kernel.org, dborkman@redhat.com,
hannes@stressinduktion.org, cwang@twopensource.com
Subject: Re: [RFC PATCH] pktgen: skb bursting via skb->xmit_more API
Date: Wed, 27 Aug 2014 14:36:52 -0700 (PDT) [thread overview]
Message-ID: <20140827.143652.79895672305012694.davem@davemloft.net> (raw)
In-Reply-To: <20140827211300.26976.52104.stgit@dragon>
From: Jesper Dangaard Brouer <brouer@redhat.com>
Date: Wed, 27 Aug 2014 23:13:00 +0200
> This patch just demonstrates the effect of delaying the HW tailptr,
> the skb->xmit_more API should likely have some wrappers.
>
> One issue is the possible need to flush/write the tailptr on
> the exit path... marked with FIXME.
...
> Performance
> skb_burst=0 tx:5614370 pps
> skb_burst=1 tx:5571279 pps ( -1.38 ns (worse))
> skb_burst=2 tx:6942821 pps ( 35.46 ns)
> skb_burst=3 tx:7556214 pps ( 11.69 ns)
> skb_burst=4 tx:7740632 pps ( 3.15 ns)
> skb_burst=5 tx:7972489 pps ( 3.76 ns)
> skb_burst=6 tx:8129856 pps ( 2.43 ns)
> skb_burst=7 tx:8281671 pps ( 2.25 ns)
> skb_burst=8 tx:8383790 pps ( 1.47 ns)
> skb_burst=9 tx:8451248 pps ( 0.95 ns)
> skb_burst=10 tx:8503571 pps ( 0.73 ns)
> skb_burst=16 tx:8745878 pps ( 3.26 ns)
> skb_burst=24 tx:8871629 pps ( 1.62 ns)
> skb_burst=32 tx:8945166 pps ( 0.93 ns)
>
> skb_burst=(0 vs 32) improvement:
> (1/5614370*10^9)-(1/8945166*10^9) = 66.32 ns
> + 3330796 pps
Thanks for doing these tests Jesper.
next prev parent reply other threads:[~2014-08-27 21:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-27 21:13 [RFC PATCH] pktgen: skb bursting via skb->xmit_more API Jesper Dangaard Brouer
2014-08-27 21:36 ` David Miller [this message]
2014-08-30 13:37 ` Jesper Dangaard Brouer
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