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[CCID3]: Ignore trivial amounts of elapsed time

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This patch fixes a previously undiscovered bug; the problem is in computing
the elapsed time as the time between `receiving' the packet (i.e. skb enters
CCID module) and sending feedback:

     - there is no layer-processing, queueing, or delay involved,
     - hence the elapsed time is in the order of 1 function call
     - this is in the dimension of maximally 50..100usec
     - which renders the use of elapsed time almost entirely useless.

The fix is simply to ignore such trivial amounts of elapsed time.

As a further advantage, the now useless elapsed_time field can be removed from
the socket, which reduces the socket structure by another four bytes.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gerrit Renker
2007-11-20 18:00:39 -02:00
committed by David S. Miller
parent 6c08b2cf48
commit eb279b79c4
2 changed files with 1 additions and 11 deletions
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2
net/dccp/ccids/ccid3.h
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@@ -147,7 +147,6 @@ enum ccid3_hc_rx_states {
* @ccid3hcrx_li_hist - Loss Interval History
* @ccid3hcrx_s - Received packet size in bytes
* @ccid3hcrx_pinv - Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
* @ccid3hcrx_elapsed_time - Time since packet reception
*/
struct ccid3_hc_rx_sock {
struct tfrc_rx_info ccid3hcrx_tfrc;
@@ -165,7 +164,6 @@ struct ccid3_hc_rx_sock {
struct list_head ccid3hcrx_li_hist;
u16 ccid3hcrx_s;
u32 ccid3hcrx_pinv;
u32 ccid3hcrx_elapsed_time;
};
static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)