Messages in this thread | | | Date | Thu, 29 Oct 2009 22:14:15 +0200 (EET) | From | "Ilpo Järvinen" <> | Subject | Re: [PATCH 3/3] net: TCP thin dupack |
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On Thu, 29 Oct 2009, apetlund@simula.no wrote:
> I apologise that some of you received this mail more than once. My email > client played a HTML-trick on me. > > >> + /* If a thin stream is detected, retransmit after first > >> + * received dupack */ > >> + if ((tp->thin_dupack || sysctl_tcp_force_thin_dupack) && > >> + tcp_dupack_heurestics(tp) > 1 && tcp_stream_is_thin(tp)) > >> + return 1; > >> + > >> return 0; > >> } > > > > Have you tested it? ...I doubt this will work like you say and > retransmit > > something when the window is small. ...Besides, you should have built > this > > patch on top of the function rename you submitted earlier as after DaveM > applied that this will no longer even compile... > > > > -- > > i. > > > > We have performed extensive tests mapping the effect of the patch you > commented on some months ago. Since then, the only change was the one you > requested of switching tcp_fackets_out() with tcp_dupack_heurestics(). > After inspecting the code, I believed the effect should be equal to the > previous, only making considerations for SACK and FACK availability. > Please tell if this will break the intended effect, and I will modify the > patch accordingly.
Ah, you're of course right. FACK retransmits the head always but RFC3517 mode doesn't. I think you'd need to artificially lower (ie., to calculate) the dupthresh (from tp->reordering) to be 1 for it to work as intented.
> Graphs from our tests of the original patch can be found at the location > linked to below. I have tested the new one for functionality, but have > not et performed tests on this scope as the changes were minor. I will, of > course, fix the function rename in the next iteration. Sorry for that. > > http://folk.uio.no/apetlund/lktmp/
You curiousity, have you run this more aggressive form of early retransmit against the one ID gives? ...I checked your results but if I understood them correctly the IDish early retransmit wasn't among the variants used.
-- i.
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