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[DCCP]: Fix CCID3

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This fixes CCID3 to give much closer performance to RFC4342.

CCID3 is meant to alter sending rate based on RTT and loss.

The performance was verified against:
http://wand.net.nz/~perry/max_download.php

For example I tested with netem and had the following parameters:
Delayed Acks 1, MSS 256 bytes, RTT 105 ms, packet loss 5%.

This gives a theoretical speed of 71.9 Kbits/s. I measured across three
runs with this patch set and got 70.1 Kbits/s. Without this patchset the
average was 232 Kbits/s which means Linux can't be used for CCID3 research
properly.

I also tested with netem turned off so box just acting as router with 1.2
msec RTT. The performance with this is the same with or without the patch
at around 30 Mbit/s.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ian McDonald
2006-08-26 23:40:50 -07:00
committed by David S. Miller
parent 3a13813e6e
commit 66a377c504
6 changed files with 155 additions and 194 deletions
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5
net/dccp/ccids/ccid3.h
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@ -120,9 +120,10 @@ struct ccid3_hc_rx_sock {
#define ccid3hcrx_x_recv ccid3hcrx_tfrc.tfrcrx_x_recv
#define ccid3hcrx_rtt ccid3hcrx_tfrc.tfrcrx_rtt
#define ccid3hcrx_p ccid3hcrx_tfrc.tfrcrx_p
u64 ccid3hcrx_seqno_last_counter:48,
u64 ccid3hcrx_seqno_nonloss:48,
ccid3hcrx_ccval_nonloss:4,
ccid3hcrx_state:8,
ccid3hcrx_last_counter:4;
ccid3hcrx_ccval_last_counter:4;
u32 ccid3hcrx_bytes_recv;
struct timeval ccid3hcrx_tstamp_last_feedback;
struct timeval ccid3hcrx_tstamp_last_ack;