From: Eric Dumazet <eric.dumazet@gmail.com>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: Or Gerlitz <gerlitz.or@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jesper Dangaard Brouer <brouer@redhat.com>,
Eric Dumazet <edumazet@google.com>,
John Fastabend <john.r.fastabend@intel.com>,
Linux Netdev List <netdev@vger.kernel.org>,
Amir Vadai <amirv@mellanox.com>,
Or Gerlitz <or.gerlitz@gmail.com>
Subject: Re: [PATCH net-next] mlx4: optimize xmit path
Date: Sun, 28 Sep 2014 11:52:44 -0700 [thread overview]
Message-ID: <1411930364.15768.80.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <CAMEtUuxwQ8k1wcT8U0VncnVoN=vZjU3zxswgjYPcQTLPw2pRwA@mail.gmail.com>
On Sun, 2014-09-28 at 11:07 -0700, Alexei Starovoitov wrote:
> this is great improvement!
> Thank you for leading this effort.
> 10G line rate is definitely nice :)
> Hopefully Or can demo similar numbers with 40G nic as well :)
>
> > + if (ring->bf_enabled && desc_size <= MAX_BF && !bounce &&
> > + !vlan_tx_tag_present(skb) && send_doorbell) {
>
> feels something wrong here, since it checks for
> send_doorbell, but iowrite() happens in the 'else' part
> of this branch with another 'if (send_doorbell)'
>
If we do not plan to send a doorbell, we should not use blueframe.
Blueframe is always sending a doorbell by design, as it uses a single
flip buffer.
So if you want to see any improvement thanks to skb->xmit_more, we have
to use the iowrite32(), not the blueframe.
Therefore , if send_doorbell == false, we do not want the doorbell
Is it making sense now ? ;)
next prev parent reply other threads:[~2014-09-28 18:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-28 18:07 [PATCH net-next] mlx4: optimize xmit path Alexei Starovoitov
2014-09-28 18:52 ` Eric Dumazet [this message]
2014-09-28 20:49 ` Alexei Starovoitov
2014-09-29 2:22 ` Eric Dumazet
2014-09-29 5:08 ` Alexei Starovoitov
-- strict thread matches above, loose matches on Subject: below --
2014-09-26 0:46 [RFC PATCH net-next] net: pktgen: packet bursting via skb->xmit_more Alexei Starovoitov
2014-09-26 1:20 ` Eric Dumazet
2014-09-26 7:42 ` Eric Dumazet
2014-09-27 20:43 ` Eric Dumazet
2014-09-27 20:55 ` Or Gerlitz
2014-09-27 21:30 ` Eric Dumazet
2014-09-27 22:56 ` [PATCH net-next] mlx4: optimize xmit path Eric Dumazet
2014-09-27 23:44 ` Hannes Frederic Sowa
2014-09-28 0:05 ` Eric Dumazet
2014-09-28 0:22 ` Hannes Frederic Sowa
2014-09-28 12:42 ` Eric Dumazet
2014-09-28 14:35 ` Or Gerlitz
2014-09-28 16:03 ` Eric Dumazet
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