On Tue, 2016-09-06 at 18:32 -0700, Francis Y. Yan wrote: > This patch measures the total time when TCP transmission is limited > by receiver's advertised window (rwnd), and exports it in tcp_info as > tcpi_rwnd_limited. > > The rwnd-limited time is defined as the period when the next segment > to send by TCP cannot fit into rwnd. To measure it, we record the last > timestamp when limited by rwnd (rwnd_limited_ts) and the total > rwnd-limited time (rwnd_limited) in tcp_sock. > > Then we export the total rwnd-limited time so far in tcp_info, where > by so far, we mean that if TCP transmission is still being limited by > rwnd, the time interval since rwnd_limited_ts needs to be counted as > well; otherwise, we simply export rwnd_limited. > > It is worth noting that we also have to add a new sequence counter > (seqcnt) in tcp_sock to carefully handle tcp_info's reading of > rwnd_limited_ts and rwnd_limited in order to get a consistent snapshot > of both variables together. > > Signed-off-by: Francis Y. Yan <francisy...@gmail.com> > Signed-off-by: Yuchung Cheng <ych...@google.com> > ---
Acked-by: Eric Dumazet <eduma...@google.com> Thanks Francis !
