Re: [RFC PATCH net-next] tcp: add CDG congestion control

2015-06-04 Thread Dave Taht
On Thu, Jun 4, 2015 at 9:19 AM, Kenneth Klette Jonassen wrote: >> why not just call tcp_init_cwnd_reduction()? > > I deferred considering the ECN implications of doing so. The code to > start PRR was based on tcp_enter_cwr()/tcp_init_cwnd_reduction(), save > that both of these functions ensure a c

Re: [RFC PATCH net-next] tcp: add CDG congestion control

2015-06-04 Thread Kenneth Klette Jonassen
> why not just call tcp_init_cwnd_reduction()? I deferred considering the ECN implications of doing so. The code to start PRR was based on tcp_enter_cwr()/tcp_init_cwnd_reduction(), save that both of these functions ensure a call to tcp_ecn_queue_cwr(). The upcoming patch set instead exports tcp_

Re: [RFC PATCH net-next] tcp: add CDG congestion control

2015-06-04 Thread Kenneth Klette Jonassen
>> +static int window __read_mostly = 8; > > This is a (readonly) module parameter, but really is a constant (if you > ever try to change it dynamically, bad things will happen in current > code) > > const int window = 8; It cannot be adjusted dynamically, but we can override the initial window p

Re: [RFC PATCH net-next] tcp: add CDG congestion control

2015-06-04 Thread Kenneth Klette Jonassen
On Tue, May 19, 2015 at 12:16 AM, Stephen Hemminger wrote: > > I am really happy to see more congestion control development. :) > > Module parameters make for rather ugly tuning. > They are ok for testing but difficult to use in real life. CDG's throughput-delay tradeoff is affected by the para

Re: [RFC PATCH net-next] tcp: add CDG congestion control

2015-05-18 Thread Stephen Hemminger
I am really happy to see more congestion control development. > +static int window __read_mostly = 8; > +static bool use_shadow __read_mostly = true; > +static bool use_tolerance __read_mostly; > +static uint backoff_beta __read_mostly = 0.70 * 1024; > +static uint backoff_factor __read_mostly =

Re: [RFC PATCH net-next] tcp: add CDG congestion control

2015-05-18 Thread Yuchung Cheng
On Sun, May 17, 2015 at 1:31 PM, Kenneth Klette Jonassen wrote: > This is a request for comments. > > CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies > the TCP sender in order to [1]: > > o Use the delay gradient as a congestion signal. > o Back off with an average probabil