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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2006-11-27 12:22:48 -0200
committerDavid S. Miller <davem@sunset.davemloft.net>2006-12-02 21:30:36 -0800
commitf5c2d6367b04fd5ba98a5f9846b5fb870423968a (patch)
tree139687b3ec6b86b1938e7d55571880b9a88bf936
parent90feeb951f61a80d3a8f8e5ced25b9ec78867eaf (diff)
[DCCP] ccid3: Simplify control flow in the calculation of t_ipi
This patch performs a simplifying (performance) optimisation: In each call of the inline function ccid3_calc_new_t_ipi(), the state is tested against TFRC_SSTATE_NO_FBACK. This is expensive when the function is called very often. A simpler solution, implemented by this patch, is to adapt the control flow. Background:
-rw-r--r--net/dccp/ccids/ccid3.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index d7b688e9f98..df88c54b2ec 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -103,13 +103,7 @@ static void ccid3_hc_tx_set_state(struct sock *sk,
/* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
static inline void ccid3_calc_new_t_ipi(struct ccid3_hc_tx_sock *hctx)
{
- /*
- * If no feedback spec says t_ipi is 1 second (set elsewhere and then
- * doubles after every no feedback timer (separate function)
- */
- if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
- hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s,
- hctx->ccid3hctx_x);
+ hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_x);
}
/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
@@ -395,6 +389,8 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
"as a data packet", dccp_role(sk));
return;
case TFRC_SSTATE_NO_FBACK:
+ /* t_nom, t_ipi, delta do not change until feedback arrives */
+ return;
case TFRC_SSTATE_FBACK:
if (len > 0) {
timeval_sub_usecs(&hctx->ccid3hctx_t_nom,