[CCID 3]: Macro for moving average
The moving average computation occurs so frequently in the CCID 3 code that
it merits a macro of its own.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
net/dccp/ccids/ccid3.c | 8 +++-----
net/dccp/ccids/lib/tfrc.h | 8 ++++++++
2 files changed, 11 insertions(+), 5 deletions(-)
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -37,6 +37,14 @@ static inline u32 scaled_div32(u64 a, u3
return result;
}
+/**
+ * Macro for exponentially weighted moving average
+ * @weight: Weight to be used as damping factor, in units of 1/10
+ * Beware that @val is evaluated multiple times.
+ */
+#define TFRC_EWMA(val, newval, weight) \
+ val = val? ((weight) * val + (10 - (weight)) * (newval)) / 10 : (newval)
+
extern u32 tfrc_calc_x(u16 s, u32 R, u32 p);
extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -183,7 +183,7 @@ static inline void ccid3_hc_tx_update_s(
{
const u16 old_s = hctx->ccid3hctx_s;
- hctx->ccid3hctx_s = old_s == 0 ? len : (9 * old_s + len) / 10;
+ TFRC_EWMA(hctx->ccid3hctx_s, len, 9);
if (hctx->ccid3hctx_s != old_s)
ccid3_update_send_interval(hctx);
@@ -474,8 +474,7 @@ static void ccid3_hc_tx_packet_recv(stru
*
* q is a constant, RFC 3448 recommends 0.9
*/
- hctx->ccid3hctx_rtt = hctx->ccid3hctx_rtt == 0 ? r_sample
- : (9 * hctx->ccid3hctx_rtt + r_sample) / 10;
+ TFRC_EWMA(hctx->ccid3hctx_rtt, r_sample, 9);
/*
* Update allowed sending rate as per draft rfc3448bis, 4.2/4.3
@@ -724,8 +723,7 @@ static inline void ccid3_hc_rx_update_s(
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;
+ TFRC_EWMA(hcrx->ccid3hcrx_s, len, 9);
}
static void ccid3_hc_rx_send_feedback(struct sock *sk)
-
To unsubscribe from this list: send the line "unsubscribe dccp" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
