From f5c2d6367b04fd5ba98a5f9846b5fb870423968a Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Mon, 27 Nov 2006 12:22:48 -0200 Subject: [PATCH] [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: --- net/dccp/ccids/ccid3.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index d7b688e9f983..df88c54b2ec5 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,