From: Jason Wang <jasowang@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Zoltan Kiss <zoltan.kiss@citrix.com>,
Wei Liu <wei.liu2@citrix.com>,
Jonathan Davies <Jonathan.Davies@eu.citrix.com>,
Ian Campbell <ian.campbell@citrix.com>,
netdev@vger.kernel.org, xen-devel@lists.xenproject.org,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: TSQ accounting skb->truesize degrades throughput for large packets
Date: Tue, 10 Sep 2013 15:45:47 +0800 [thread overview]
Message-ID: <522ECE2B.7020409@redhat.com> (raw)
In-Reply-To: <1378734444.26319.28.camel@edumazet-glaptop>
On 09/09/2013 09:47 PM, Eric Dumazet wrote:
> On Mon, 2013-09-09 at 17:27 +0800, Jason Wang wrote:
>
>> Virtio-net orphan the skb in .ndo_start_xmit() so TSQ can not throttle
>> packets in device accurately, and it also can't do BQL. Does this means
>> TSQ should be disabled for virtio-net?
>>
> If skb are orphaned, there is no way TSQ can work at all.
For example, virtio-net will stop the tx queue when it finds the tx
queue may full and enable the queue when some packets were sent. In this
case, tsq works and throttles the total bytes queued in qdisc. This
usually happen during heavy network load such as two sessions of netperf.
>
> It is already disabled, so why do you want to disable it ?
>
>
We notice a regression, and bisect shows it was introduced by TSQ.
next prev parent reply other threads:[~2013-09-10 7:46 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-06 10:16 TSQ accounting skb->truesize degrades throughput for large packets Wei Liu
2013-09-06 12:57 ` Eric Dumazet
2013-09-06 13:12 ` Wei Liu
2013-09-06 16:36 ` Zoltan Kiss
2013-09-06 16:56 ` Eric Dumazet
2013-09-09 9:27 ` Jason Wang
2013-09-09 13:47 ` Eric Dumazet
2013-09-10 7:45 ` Jason Wang [this message]
2013-09-10 12:35 ` Eric Dumazet
2013-09-06 17:00 ` Eric Dumazet
2013-09-07 17:21 ` Eric Dumazet
2013-09-09 21:41 ` Zoltan Kiss
2013-09-09 21:56 ` Eric Dumazet
[not found] ` <loom.20130921T045654-573@post.gmane.org>
[not found] ` <20130921150327.GA9078@zion.uk.xensource.com>
2013-09-22 2:36 ` [Xen-devel] " Cong Wang
2013-09-22 14:58 ` Eric Dumazet
2013-09-27 10:28 ` [PATCH] tcp: TSQ can use a dynamic limit Eric Dumazet
2013-09-27 15:08 ` Neal Cardwell
2013-09-29 15:41 ` Cong Wang
2013-10-01 3:52 ` David Miller
2013-09-09 5:28 ` TSQ accounting skb->truesize degrades throughput for large packets Cong Wang
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