| Message ID | 1423102400-9693-10-git-send-email-thomas@net.t-labs.tu-berlin.de (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Johannes Berg |
| Headers | show |
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h index d047610..16b6e36 100644 --- a/net/mac80211/rc80211_minstrel.h +++ b/net/mac80211/rc80211_minstrel.h @@ -27,7 +27,12 @@ static inline int minstrel_ewma(int old, int new, int weight) { - return (new * (EWMA_DIV - weight) + old * weight) / EWMA_DIV; + int diff, incr; + + diff = new - old; + incr = (EWMA_DIV - weight) * diff / EWMA_DIV; + + return old + incr; } struct minstrel_rate_stats {
This patch reduces the calculation costs of the EWMA macro from "2x multiplication and 1 addition" down to "1x multiplication and 2 additions". This slightly improves performance depending on the CPU architecture. Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> --- net/mac80211/rc80211_minstrel.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)