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| author | Thomas Huehn <thomas@net.t-labs.tu-berlin.de> | 2015-03-24 21:09:42 +0100 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2015-04-01 20:44:33 +0200 |
| commit | ade6d4a2ec57d258bc181a155288c267dd8cf094 (patch) | |
| tree | 60df72e1b0f08c2f544a5ae4cfcec181f5ae0de1 /net/mac80211 | |
| parent | 50e55a8ea76fb593403cc09767b6371c17364ba8 (diff) | |
| download | blackbird-obmc-linux-ade6d4a2ec57d258bc181a155288c267dd8cf094.tar.gz blackbird-obmc-linux-ade6d4a2ec57d258bc181a155288c267dd8cf094.zip | |
mac80211: reduce calculation costs of EWMA
This patch reduces the calculation costs of the EWMA macro from
"2x multiplication and 1 addition" down to "1x multiplication and
2x additions". This slightly improves performance depending on the
CPU architecture.
Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211')
| -rw-r--r-- | net/mac80211/rc80211_minstrel.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h index 0083036161af..9c85a610b57b 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 { |
