ath9k: Optimize TBTT/DTIM calculation for timers (267a9012) · Commits · 戴 / test

The previous version used a simple loop to go through all Beacon frames when determining the next TBTT and DTIM count. This is not too bad for the case where the setup happens before timesync (i.e., very small TSF), but this can become very heavy operation if a short Beacon interval is used and the current TSF is large. In preparation for a patch to update timer setup based on Beacon timestamp, optimize this routine to take fixed time regardless of the actual TSF value. Signed-off-by:

Jouni Malinen <jouni.malinen@atheros.com> Signed-off-by:

John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/beacon.c

+21 −7

Original line number	Diff line number	Diff line
		@@ -559,6 +559,7 @@ static void ath_beacon_config_sta(struct ath_softc *sc,
		int cfpperiod, cfpcount;
		u32 nexttbtt = 0, intval, tsftu;
		u64 tsf;
		int num_beacons, offset, dtim_dec_count, cfp_dec_count;

		memset(&bs, 0, sizeof(bs));
		intval = conf->beacon_interval & ATH9K_BEACON_PERIOD;
		@@ -586,14 +587,27 @@ static void ath_beacon_config_sta(struct ath_softc *sc,
		*/
		tsf = ath9k_hw_gettsf64(sc->sc_ah);
		tsftu = TSF_TO_TU(tsf>>32, tsf) + FUDGE;
		do {

		num_beacons = tsftu / intval + 1;
		offset = tsftu % intval;
		nexttbtt = tsftu - offset;
		if (offset)
		nexttbtt += intval;
		if (--dtimcount < 0) {
		dtimcount = dtimperiod - 1;
		if (--cfpcount < 0)
		cfpcount = cfpperiod - 1;
		}
		} while (nexttbtt < tsftu);

		/* DTIM Beacon every dtimperiod Beacon */
		dtim_dec_count = num_beacons % dtimperiod;
		/* CFP every cfpperiod DTIM Beacon */
		cfp_dec_count = (num_beacons / dtimperiod) % cfpperiod;
		if (dtim_dec_count)
		cfp_dec_count++;

		dtimcount -= dtim_dec_count;
		if (dtimcount < 0)
		dtimcount += dtimperiod;

		cfpcount -= cfp_dec_count;
		if (cfpcount < 0)
		cfpcount += cfpperiod;

		bs.bs_intval = intval;
		bs.bs_nexttbtt = nexttbtt;

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