mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
[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>
This commit is contained in:
parent
6c08b2cf48
commit
eb279b79c4
@ -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,
|
||||
|
@ -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)
|
||||
|
Loading…
Reference in New Issue
Block a user