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| author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2006-11-27 12:22:48 -0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-12-02 21:30:36 -0800 |
| commit | f5c2d6367b04fd5ba98a5f9846b5fb870423968a (patch) | |
| tree | 139687b3ec6b86b1938e7d55571880b9a88bf936 | |
| parent | 90feeb951f61a80d3a8f8e5ced25b9ec78867eaf (diff) | |
| download | linux-f5c2d6367b04fd5ba98a5f9846b5fb870423968a.tar.bz2 | |
[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.c | 10 |
1 files 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, |