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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Dave Taht <dave.taht@gmail.com>
Cc: "Tom Herbert" <therbert@google.com>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	"Linux Netdev List" <netdev@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	"Alexander Duyck" <alexander.h.duyck@intel.com>,
	"Toke Høiland-Jørgensen" <toke@toke.dk>,
	"Florian Westphal" <fw@strlen.de>,
	"Jamal Hadi Salim" <jhs@mojatatu.com>,
	"John Fastabend" <john.r.fastabend@intel.com>,
	"Daniel Borkmann" <dborkman@redhat.com>,
	"Hannes Frederic Sowa" <hannes@stressinduktion.org>
Subject: Re: [net-next PATCH 1/1 V4] qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE
Date: Fri, 26 Sep 2014 11:06:37 -0700	[thread overview]
Message-ID: <1411754797.16953.134.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <CAA93jw7Y5-5qwTcoqzRAv-DeRmVUA=hTX6b74hQPM=VmpNWQZA@mail.gmail.com>

On Wed, 2014-09-24 at 19:58 -0700, Dave Taht wrote:

> I have long hoped that the actual BQL limit in play would feed into
> TCP small queues when there are a lot of flows to make each tcp
> "small" queue gradually smaller...

Yep, but what do you do if you have 64 TX queues, each one having
different BQL limits ? This looks like a NP problem when you also have
millions of tcp flows.

Basically BQL limit is more a sign of local host being able to drain TX
completions fast or not.

Here at Google, we have a very tiny queue of at most 2 packets per flow,
and srtt being in usec units gives us a very dynamic signal, based on
end to end measures.

I am experimenting moving TSQ processing from tasklet to workqueue,
because we need faster response to {soft}irq when we so often enter
TCP stack.

  reply	other threads:[~2014-09-26 18:06 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-24 16:10 [net-next PATCH 0/1 V4] qdisc bulk dequeuing and utilizing delayed tailptr updates Jesper Dangaard Brouer
2014-09-24 16:12 ` [net-next PATCH 1/1 V4] qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE Jesper Dangaard Brouer
2014-09-24 17:23   ` Eric Dumazet
2014-09-24 17:58     ` Jesper Dangaard Brouer
2014-09-24 18:34       ` Tom Herbert
2014-09-24 19:22         ` Eric Dumazet
2014-09-25  2:12           ` Eric Dumazet
2014-09-25  2:38             ` Tom Herbert
2014-09-25  2:58               ` Dave Taht
2014-09-26 18:06                 ` Eric Dumazet [this message]
2014-09-25 23:40             ` Eric Dumazet
2014-09-26  6:04               ` [PATCH net-next] dql: dql_queued() should write first to reduce bus transactions Eric Dumazet
2014-09-26  8:47                 ` Jesper Dangaard Brouer
2014-09-26 11:06                 ` Hannes Frederic Sowa
2014-09-26 12:02                   ` Eric Dumazet
2014-09-28 21:43                 ` David Miller
2014-09-26  9:23               ` [net-next PATCH 1/1 V4] qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE David Laight
2014-09-26 13:16                 ` David Laight
2014-09-26 13:38                   ` Eric Dumazet
2014-09-24 22:13       ` Jamal Hadi Salim
2014-09-25  8:25         ` Jesper Dangaard Brouer
2014-09-25 12:48           ` Jamal Hadi Salim
2014-09-25 14:40             ` Tom Herbert
2014-09-25 14:57               ` Jesper Dangaard Brouer
2014-09-25 15:05                 ` Tom Herbert
2014-09-25 15:23                   ` Jesper Dangaard Brouer
2014-09-25 15:58                     ` Tom Herbert
2014-09-29 20:23                       ` Jesper Dangaard Brouer
2014-09-29 20:14                     ` Jesper Dangaard Brouer
2014-09-25 15:12                 ` Eric Dumazet
2014-09-25 13:52           ` Dave Taht

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