[CCID3]: Inline for moving average
The moving average computation occurs so frequently in the CCID 3 code that
it merits an inline function of its own. This is uses a suggestion by
Arnaldo as per http://www.mail-archive.com/dccp@vger.kernel.org/msg01662.html
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>
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 94a3228..42893b1 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -192,7 +192,7 @@
{
const u16 old_s = hctx->ccid3hctx_s;
- hctx->ccid3hctx_s = old_s == 0 ? len : (9 * old_s + len) / 10;
+ hctx->ccid3hctx_s = tfrc_ewma(hctx->ccid3hctx_s, len, 9);
if (hctx->ccid3hctx_s != old_s)
ccid3_update_send_interval(hctx);
@@ -449,25 +449,15 @@
now = ktime_get_real();
/*
- * Calculate new round trip sample as per [RFC 3448, 4.3] by
- * R_sample = (now - t_recvdata) - t_elapsed
+ * Calculate new RTT sample and update moving average
*/
r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, packet->dccphtx_tstamp));
+ hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9);
- /*
- * Update RTT estimate by
- * If (No feedback recv)
- * R = R_sample;
- * Else
- * R = q * R + (1 - q) * R_sample;
- *
- * q is a constant, RFC 3448 recomments 0.9
- */
if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
/*
* Larger Initial Windows [RFC 4342, sec. 5]
*/
- hctx->ccid3hctx_rtt = r_sample;
hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
hctx->ccid3hctx_t_ld = now;
@@ -481,8 +471,6 @@
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
} else {
- hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
- r_sample) / 10;
/* Update sending rate (step 4 of [RFC 3448, 4.3]) */
if (hctx->ccid3hctx_p > 0)
@@ -700,11 +688,8 @@
static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
{
- if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
- ccid3_pr_debug("Packet payload length is 0 - not updating\n");
- else
- hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
- (9 * hcrx->ccid3hcrx_s + len) / 10;
+ if (likely(len > 0)) /* don't update on empty packets (e.g. ACKs) */
+ hcrx->ccid3hcrx_s = tfrc_ewma(hcrx->ccid3hcrx_s, len, 9);
}
static void ccid3_hc_rx_send_feedback(struct sock *sk)