From: Rick Jones <rick.jones2@hp.com>
To: Eric Dumazet <eric.dumazet@gmail.com>,
David Miller <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>,
Or Gerlitz <ogerlitz@mellanox.com>,
Willem de Bruijn <willemb@google.com>
Subject: Re: [PATCH net-next] net: gro: add a per device gro flush timer
Date: Wed, 05 Nov 2014 17:38:35 -0800 [thread overview]
Message-ID: <545AD11B.5050603@hp.com> (raw)
In-Reply-To: <1415235320.13896.51.camel@edumazet-glaptop2.roam.corp.google.com>
On 11/05/2014 04:55 PM, Eric Dumazet wrote:
> Tested:
> Ran 200 netperf TCP_STREAM from A to B (10Gbe link, 8 RX queues)
>
> Without this feature, we send back about 305,000 ACK per second.
>
> GRO aggregation ratio is low (811/305 = 2.65 segments per GRO packet)
>
> Setting a timer of 2000 nsec is enough to increase GRO packet sizes
> and reduce number of ACK packets. (811/19.2 = 42)
>
> Receiver performs less calls to upper stacks, less wakes up.
> This also reduces cpu usage on the sender, as it receives less ACK
> packets.
>
> Note that reducing number of wakes up increases cpu efficiency, but can
> decrease QPS, as applications wont have the chance to warmup cpu caches
> doing a partial read of RPC requests/answers if they fit in one skb.
Speaking of QPS, what happens to 200 TCP_RR tests when the feature is
enabled?
rick jones
next prev parent reply other threads:[~2014-11-06 1:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-06 0:55 [PATCH net-next] net: gro: add a per device gro flush timer Eric Dumazet
2014-11-06 1:38 ` Rick Jones [this message]
2014-11-06 2:14 ` Eric Dumazet
2014-11-06 2:39 ` Eric Dumazet
2014-11-06 16:42 ` Rick Jones
2014-11-06 21:25 ` David Miller
2014-11-06 22:11 ` Eric Dumazet
2014-11-07 3:36 ` David Miller
2014-11-07 4:15 ` Eric Dumazet
2014-11-07 5:09 ` [PATCH v2 net-next 1/2] " Eric Dumazet
2014-11-07 22:00 ` David Miller
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