[Bloat] TCP BBR paper is now generally available

[Eric Dumazet]

On Sun, 2016-12-04 at 00:03 +0100, Steinar H. Gunderson wrote:
> On Sat, Dec 03, 2016 at 02:55:37PM -0800, Eric Dumazet wrote:
> > Note that starting from linux-4.4, e1000e gets gro_flush_timeout that
> > would help this precise workload
> > 
> > https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=32b3e08fff60494cd1d281a39b51583edfd2b18f
> > 
> > Maybe you can redo the experiment in ~5 years when distro catches up ;)
> 
> I can always find a backport, assuming the IPMI is still working. But it
> really wasn't like this earlier :-) Perhaps something changed on the path,
> unrelated to BBR.

If the tcpdump is taken on receiver, how would you explain these gaps ?
Like the NIC was frozen for 40 ms  !

11:14:06.023821 IP6 C > S: Flags [.], ack 368888520, win 23422, options [nop,nop,TS val 864457007 ecr 3498315976], length 0
11:14:06.023823 IP6 C > S: Flags [.], ack 368891028, win 23430, options [nop,nop,TS val 864457007 ecr 3498315976], length 0
11:14:06.023829 IP6 C > S: Flags [.], ack 368899248, win 23407, options [nop,nop,TS val 864457007 ecr 3498315976], length 0
11:14:06.023834 IP6 C > S: Flags [.], ack 368907468, win 23415, options [nop,nop,TS val 864457007 ecr 3498315976], length 0
11:14:06.023835 IP6 C > S: Flags [.], ack 368915688, win 23392, options [nop,nop,TS val 864457007 ecr 3498315976], length 0
<gap : Not tsval is still 864457007 >
11:14:06.062751 IP6 C > S: Flags [.], ack 368923908, win 23415, options [nop,nop,TS val 864457007 ecr 3498315977], length 0
11:14:06.062767 IP6 C > S: Flags [.], ack 368929620, win 23400, options [nop,nop,TS val 864457007 ecr 3498315977], length 0
11:14:06.062770 IP6 C > S: Flags [.], ack 368932128, win 23430, options [nop,nop,TS val 864457007 ecr 3498315977], length 0
11:14:06.062771 IP6 C > S: Flags [.], ack 368943204, win 23400, options [nop,nop,TS val 864457007 ecr 3498315977], length 0
11:14:06.062773 IP6 C > S: Flags [.], ack 368948568, win 23422, options [nop,nop,TS val 864457008 ecr 3498315977], length 0
11:14:06.062775 IP6 C > S: Flags [.], ack 368956788, win 23400, options [nop,nop,TS val 864457008 ecr 3498315977], length 0
11:14:06.062776 IP6 C > S: Flags [.], ack 368965008, win 23415, options [nop,nop,TS val 864457008 ecr 3498315977], length 0
11:14:06.062778 IP6 C > S: Flags [.], ack 368976084, win 23385, options [nop,nop,TS val 864457008 ecr 3498315977], length 0