Re: [PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-19 Thread Eric Dumazet
> > It generates some slightly smaller code. > if (bbr->lt_rtt_cnt < bbr_lt_intvl_min_rtts) > - 3e7: 0f b6 c0movzbl %al,%eax > - 3ea: 83 f8 03cmp$0x3,%eax > - 3ed: 0f 86 d4 00 00 00 jbe4c7 > + 3e7: 3c 03

Re: [PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-19 Thread Stephen Hemminger
On Mon, 19 Sep 2016 14:10:39 -0700 Eric Dumazet wrote: > On Mon, Sep 19, 2016 at 1:57 PM, Stephen Hemminger > wrote: > > > Looks good, but could I suggest a simple optimization. > > All these parameters are immutable in the version of BBR you

Re: [PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-19 Thread Eric Dumazet
On Mon, Sep 19, 2016 at 2:17 PM, Rick Jones wrote: > > Are there better than epsilon odds of someone perhaps wanting to poke those > values as it gets exposure beyond Google? > This does not matter. A change would require patching net/ipv4/tcp_bbr.c , and the 'const'

Re: [PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-19 Thread Rick Jones
On 09/19/2016 02:10 PM, Eric Dumazet wrote: On Mon, Sep 19, 2016 at 1:57 PM, Stephen Hemminger wrote: Looks good, but could I suggest a simple optimization. All these parameters are immutable in the version of BBR you are submitting. Why not make the values const?

Re: [PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-19 Thread Eric Dumazet
On Mon, Sep 19, 2016 at 1:57 PM, Stephen Hemminger wrote: > Looks good, but could I suggest a simple optimization. > All these parameters are immutable in the version of BBR you are submitting. > Why not make the values const? And eliminate the always true long-term

Re: [PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-19 Thread Stephen Hemminger
On Sun, 18 Sep 2016 18:03:53 -0400 Neal Cardwell wrote: > +static int bbr_bw_rtts = CYCLE_LEN + 2; /* win len of bw filter (in > rounds) */ > +static u32 bbr_min_rtt_win_sec = 10; /* min RTT filter window (in sec) */ > +static u32 bbr_probe_rtt_mode_ms = 200;

Re: [PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-18 Thread Neal Cardwell
On Sun, Sep 18, 2016 at 9:18 PM, Kenneth Klette Jonassen wrote: >> +static u64 bbr_rate_kbps(struct sock *sk, u64 rate) >> +{ >> + return bbr_rate_bytes_per_sec(sk, rate, BBR_UNIT) * 8 / 1000; > > > Consider div_u64() here to keep all builds happy. :-) This adds

[PATCH v3 net-next 16/16] tcp_bbr: add BBR congestion control

2016-09-18 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