Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-30 Thread Lawrence Brakmo
I ran some BBR tests under different scenarios and I am concerned that under some conditions BBR can become very aggressive. It seems BBR flows can decide that losses are un-correlated to congestion, and when in this mode, they will maintain large cwnds regardless of the losses. In cases when BBR

Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-20 Thread Neal Cardwell
On Tue, Sep 20, 2016 at 2:50 PM, Neal Cardwell wrote: > On Tue, Sep 20, 2016 at 2:48 PM, Stephen Hemminger > wrote: >> >> On Mon, 19 Sep 2016 23:39:23 -0400 >> Neal Cardwell wrote: >> >> > +/* INET_DIAG_BBRINFO */ >> > + >>

Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-20 Thread Eric Dumazet
On Tue, Sep 20, 2016 at 4:42 PM, Neal Cardwell wrote: > > On Tue, Sep 20, 2016 at 7:39 PM, Stephen Hemminger > wrote: > > > >> NOTE: BBR *must* be used with the fq qdisc ("man tc-fq") with pacing > >> enabled, since pacing is integral to the BBR

Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-20 Thread Neal Cardwell
On Tue, Sep 20, 2016 at 7:39 PM, Stephen Hemminger wrote: > >> NOTE: BBR *must* be used with the fq qdisc ("man tc-fq") with pacing >> enabled, since pacing is integral to the BBR design and >> implementation. BBR without pacing would not function properly, and >> may

Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-20 Thread Stephen Hemminger
> NOTE: BBR *must* be used with the fq qdisc ("man tc-fq") with pacing > enabled, since pacing is integral to the BBR design and > implementation. BBR without pacing would not function properly, and > may incur unnecessary high packet loss rates. Does it work with fq_codel?

Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-20 Thread Yuchung Cheng
On Tue, Sep 20, 2016 at 11:48 AM, Stephen Hemminger wrote: > On Mon, 19 Sep 2016 23:39:23 -0400 > Neal Cardwell wrote: > >> +/* INET_DIAG_BBRINFO */ >> + >> +struct tcp_bbr_info { >> + /* u64 bw: max-filtered BW (app throughput) estimate in

Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-20 Thread Neal Cardwell
On Tue, Sep 20, 2016 at 2:48 PM, Stephen Hemminger wrote: > > On Mon, 19 Sep 2016 23:39:23 -0400 > Neal Cardwell wrote: > > > +/* INET_DIAG_BBRINFO */ > > + > > +struct tcp_bbr_info { > > + /* u64 bw: max-filtered BW (app throughput) estimate

Re: [PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-20 Thread Stephen Hemminger
On Mon, 19 Sep 2016 23:39:23 -0400 Neal Cardwell wrote: > +/* INET_DIAG_BBRINFO */ > + > +struct tcp_bbr_info { > + /* u64 bw: max-filtered BW (app throughput) estimate in Byte per sec: */ > + __u32 bbr_bw_lo; /* lower 32 bits of bw */ > + __u32

[PATCH v4 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-19 Thread Neal Cardwell
This commit implements a new TCP congestion control algorithm: BBR (Bottleneck Bandwidth and RTT). A detailed description of BBR will be published in ACM Queue, Vol. 14 No. 5, September-October 2016, as "BBR: Congestion-Based Congestion Control". BBR has significantly increased throughput and