Date: Thu, 25 Jan 2001 11:17:51 -0500 (EST) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: jayanth <jayanth@yahoo-inc.com> Cc: net@FreeBSD.ORG Subject: Re: I have delayed ACK problems Message-ID: <200101251617.LAA83006@khavrinen.lcs.mit.edu> In-Reply-To: <20010125002509.A77051@yahoo-inc.com> References: <77394.980367750@winston.osd.bsdi.com> <Pine.BSF.4.21.0101250840280.48291-100000@besplex.bde.org> <20010125002509.A77051@yahoo-inc.com>
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<<On Thu, 25 Jan 2001 00:25:10 -0800, jayanth <jayanth@yahoo-inc.com> said:
> could you test this patch and compare the results.
> By generating an ACK for every segment with the TH_PSH flag set
> I found a significant increase in throughput.
I don't think this is right.
I think what we want to do is:
if (callout_pending(tp->tt_delack)) {
callout_stop(tp->tt_delack);
tp->t_flags |= TF_ACKNOW;
} else
callout_reset(...)
This has the effect of ACKing every other packet. This should
probably be encapsulated in a macro:
#define MAYBE_DELAYED_ACK(tp) \
do { \
if (tcp_delack_enabled) { \
if (callout_pending(tp->tt_delack)) { \
callout_stop(tp->tt_delack); \
tp->t_flags |= TF_ACKNOW; \
} else \
callout_reset(tp->tt_delack, \
tcp_delacktime, \
tcp_timer_delack, tp); \
} else \
tp->t_flags |= TF_ACKNOW; \
while (0)
(It may be possible to eliminate the callout_stop() call and one of
the `if' statements.)
-GAWollman
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