diff options
| author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2007-11-20 20:00:39 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-01-28 22:54:42 (GMT) |
| commit | eb279b79c46be767ecffadaa8ed6be3e3555e93d (patch) | |
| tree | f7695df96e2d129beb65263617ac7ed533e1689a /net | |
| parent | 6c08b2cf4843788e66a5e69b5512538e686ae3e3 (diff) | |
| download | linux-eb279b79c46be767ecffadaa8ed6be3e3555e93d.tar.xz | |
[CCID3]: Ignore trivial amounts of elapsed time
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/dccp/ccids/ccid3.c | 10 | ||||
| -rw-r--r-- | net/dccp/ccids/ccid3.h | 2 |
2 files changed, 1 insertions, 11 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index 5bf110b..c025236 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -744,11 +744,6 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk) hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval; hcrx->ccid3hcrx_bytes_recv = 0; - /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */ - delta = ktime_us_delta(now, packet->dccphrx_tstamp); - DCCP_BUG_ON(delta < 0); - hcrx->ccid3hcrx_elapsed_time = delta / 10; - if (hcrx->ccid3hcrx_p == 0) hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */ else if (hcrx->ccid3hcrx_p > 1000000) { @@ -778,10 +773,7 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) x_recv = htonl(hcrx->ccid3hcrx_x_recv); pinv = htonl(hcrx->ccid3hcrx_pinv); - if ((hcrx->ccid3hcrx_elapsed_time != 0 && - dccp_insert_option_elapsed_time(sk, skb, - hcrx->ccid3hcrx_elapsed_time)) || - dccp_insert_option_timestamp(sk, skb) || + if (dccp_insert_option_timestamp(sk, skb) || dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE, &pinv, sizeof(pinv)) || dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE, diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h index 0cdc982..83467c3 100644 --- a/net/dccp/ccids/ccid3.h +++ b/net/dccp/ccids/ccid3.h @@ -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) |