Messages in this thread | | | Date | Thu, 10 Sep 1998 20:23:06 +0200 (CEST) | From | Rik van Riel <> | Subject | Re: Very poor TCP/SACK performance |
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On 9 Sep 1998, Mark Gray wrote: > Jeff DeFouw <mrj@i2k.com> writes: > > On Tue, 8 Sep 1998, David S. Miller wrote: > > > > > One thing you can try to alleviate this situation is to up the default > > > window sizes a bit using the knobs in: > > They're already set to 65535, but I don't understand how increasing a > I think ppp over modem is a special case where a larger window is very > often bad depending on what hardware is in between --- the reason > (IMO) is that most of window is going to get queued up in your ISP at > the choke point --- their terminal controller/modem hardware --- and a > large window might be big enough to tickle problems on their end.
I tried reducing the window size, and it gives me some 10% more bandwidth and a more responsive connection over my 28.8 PPP link to university.
Maybe Linux should reduce the window size if it detects a lot of out-of-order packets coming in. If the TCP code has a way of knowing the properties of the connection networking is done over, it might be able to set these flags itself.
ie: if(small_buffer_other_side && lots_out_of_order()) size--;
Networking guys, what about this?
Rik. +-------------------------------------------------------------------+ | Linux memory management tour guide. H.H.vanRiel@phys.uu.nl | | Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ | +-------------------------------------------------------------------+
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