[PATCH V2 net-next] tcp: increase size at which tcp_bound_to_half_wnd bounds to > TCP_MSS_DEFAULT
In previous commit 01f83d69844d307be2aa6fea88b0e8fe5cbdb2f4 the following comments were added: "When peer uses tiny windows, there is no use in packetizing to sub-MSS pieces for the sake of SWS or making sure there are enough packets in the pipe for fast recovery." The test should be > TCP_MSS_DEFAULT not >= 512. This allows low end devices that send an MSS of 536 (TCP_MSS_DEFAULT) to see better network performance by sending it 536 bytes of data at a time instead of bounding to half window size (268). Other network stacks work this way, e.g. HP-UX. Signed-off-by: Shane Seymour --- Changed from V1 - patch reversed, Doh!, corrected patch. --- a/include/net/tcp.h 2016-06-15 17:19:21.964821477 -0500 +++ b/include/net/tcp.h 2016-06-23 20:59:14.521686048 -0500 @@ -589,7 +589,7 @@ static inline int tcp_bound_to_half_wnd( * On the other hand, for extremely large MSS devices, handling * smaller than MSS windows in this way does make sense. */ - if (tp->max_window >= 512) + if (tp->max_window > TCP_MSS_DEFAULT) cutoff = (tp->max_window >> 1); else cutoff = tp->max_window;
RE: [PATCH net-next] tcp: increase size at which tcp_bound_to_half_wnd bounds to > TCP_MSS_DEFAULT
> From: Eric Dumazet [mailto:eric.duma...@gmail.com] > Your diff is reversed. Sorry my apologies, I'll send a V2.
RE: [PATCH net-next] tcp: increase size at which tcp_bound_to_half_wnd bounds to > TCP_MSS_DEFAULT
> From: Eric Dumazet [mailto:eric.duma...@gmail.com] > Trying to cope with ridiculous windows these days is really a waste of > time, as we perform this check for all tcp sendmsg() calls :( I don't disagree with you but unfortunately there are still devices out there like this and probably will be for a long time. > Anyway, your patch is reversed. I'm not sure what you mean by reversed, I didn't change the direction of the test in the code just what it's being compared against and so it's greater than not greater than or equal to. Unless auto-correction changed reviewed to reversed?
[PATCH net-next] tcp: increase size at which tcp_bound_to_half_wnd bounds to > TCP_MSS_DEFAULT
In previous commit 01f83d69844d307be2aa6fea88b0e8fe5cbdb2f4 the following comments were added: "When peer uses tiny windows, there is no use in packetizing to sub-MSS pieces for the sake of SWS or making sure there are enough packets in the pipe for fast recovery." The test should be > TCP_MSS_DEFAULT not >= 512. This allows low end devices that send an MSS of 536 (TCP_MSS_DEFAULT) to see better network performance by sending it 536 bytes of data at a time instead of bounding to half window size (268). Other network stacks work this way, e.g. HP-UX. Signed-off-by: Shane Seymour --- --- b/include/net/tcp.h 2016-06-23 20:59:14.521686048 -0500 +++ a/include/net/tcp.h 2016-06-15 17:19:21.964821477 -0500 @@ -589,7 +589,7 @@ static inline int tcp_bound_to_half_wnd( * On the other hand, for extremely large MSS devices, handling * smaller than MSS windows in this way does make sense. */ - if (tp->max_window > TCP_MSS_DEFAULT) + if (tp->max_window >= 512) cutoff = (tp->max_window >> 1); else cutoff = tp->max_window;
