sample.c

Linux下wifi实现

void
ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
	int shortPreamble, size_t frameLen,
	u_int8_t *rix, int *try0, u_int8_t *txrate)
{
	struct sample_node *sn = ATH_NODE_SAMPLE(an);
	struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
	struct ieee80211com *ic = &sc->sc_ic;
	int ndx, size_bin, mrr, best_ndx, change_rates;
	unsigned average_tx_time;

	if (sn->num_rates <= 0) {
		printk(KERN_WARNING "%s: no rates for %s?\n",
		       dev_info, 
		       ether_sprintf(an->an_node.ni_macaddr));
		return;
	}

	mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT) && ENABLE_MRR;
	size_bin = size_to_bin(frameLen);
	best_ndx = best_rate_ndx(sn, size_bin, !mrr);

	if (best_ndx >= 0)
		average_tx_time = sn->stats[size_bin][best_ndx].average_tx_time;
	else
		average_tx_time = 0;
	
	if (sn->static_rate_ndx != -1) {
		ndx = sn->static_rate_ndx;
		*try0 = ATH_TXMAXTRY;
	} else {
		*try0 = mrr ? 2 : ATH_TXMAXTRY;
		
		if (sn->sample_tt[size_bin] < average_tx_time * (sn->packets_since_sample[size_bin] * ssc->ath_sample_rate / 100)) {
			/*
			 * we want to limit the time measuring the performance
			 * of other bit-rates to ath_sample_rate% of the
			 * total transmission time.
			 */
			ndx = pick_sample_ndx(sn, size_bin);
			if (ndx != sn->current_rate[size_bin])
				sn->current_sample_ndx[size_bin] = ndx;
			else
				sn->current_sample_ndx[size_bin] = -1;
			sn->packets_since_sample[size_bin] = 0;

		} else {
			change_rates = 0;
			if (!sn->packets_sent[size_bin] || best_ndx == -1) {
				/* no packet has been sent successfully yet, so
				 * pick an rssi-appropriate bit-rate. We know if
				 * the rssi is very low that the really high
				 * bit rates will not work.
				 */
				int initial_rate = 72;
				if (an->an_avgrssi > 50) {
					initial_rate = 108; /* 54 mbps */
				} else if (an->an_avgrssi > 30) {
					initial_rate = 72; /* 36 mbps */
				} else {
					initial_rate = 22; /* 11 mbps */
				}

				for (ndx = sn->num_rates-1; ndx > 0; ndx--) {
					/* 
					 * pick the highest rate <= initial_rate/2 Mbps
					 * that hasn't failed.
					 */
					if (sn->rates[ndx].rate <= initial_rate && 
					    sn->stats[size_bin][ndx].successive_failures == 0)
						break;
				}
				change_rates = 1;
				best_ndx = ndx;
			} else if (sn->packets_sent[size_bin] < 20) {
				/* let the bit-rate switch quickly during the first few packets */
				change_rates = 1;
			} else if (jiffies - ((HZ * MIN_SWITCH_MS) / 1000) > sn->jiffies_since_switch[size_bin]) {
				/* 2 seconds have gone by */
				change_rates = 1;
			} else if (average_tx_time * 2 < sn->stats[size_bin][sn->current_rate[size_bin]].average_tx_time) {
				/* the current bit-rate is twice as slow as the best one */
				change_rates = 1;
			}

			sn->packets_since_sample[size_bin]++;
			
			if (change_rates) {
				if (best_ndx != sn->current_rate[size_bin]) {
					DPRINTF(sc, "%s: %s size %d switch rate %d (%d/%d) -> %d (%d/%d) after %d packets mrr %d\n",
						dev_info,
						ether_sprintf(an->an_node.ni_macaddr),
						packet_size_bins[size_bin],
						sn->rates[sn->current_rate[size_bin]].rate,
						sn->stats[size_bin][sn->current_rate[size_bin]].average_tx_time,
						sn->stats[size_bin][sn->current_rate[size_bin]].perfect_tx_time,
						sn->rates[best_ndx].rate,
						sn->stats[size_bin][best_ndx].average_tx_time,
						sn->stats[size_bin][best_ndx].perfect_tx_time,
						sn->packets_since_switch[size_bin],
						mrr);
				}
				sn->packets_since_switch[size_bin] = 0;
				sn->current_rate[size_bin] = best_ndx;
				sn->jiffies_since_switch[size_bin] = jiffies;
			}
			ndx = sn->current_rate[size_bin];
			sn->packets_since_switch[size_bin]++;
			if (size_bin == 0) {
	    			/* 
	    			 * set the visible txrate for this node
			         * to the rate of small packets
			         */
				an->an_node.ni_txrate = ndx;
			}
		}
	}

	KASSERT(ndx >= 0 && ndx < sn->num_rates, 
		("%s: bad ndx (%d/%d) for %s?\n",
		 dev_info, ndx, sn->num_rates, 
		 ether_sprintf(an->an_node.ni_macaddr)));
		

	*rix = sn->rates[ndx].rix;
	if (shortPreamble)
		*txrate = sn->rates[ndx].shortPreambleRateCode;
	else
		*txrate = sn->rates[ndx].rateCode;
	sn->packets_sent[size_bin]++;
}
EXPORT_SYMBOL(ath_rate_findrate);

void
ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
	struct ath_desc *ds, int shortPreamble, size_t frame_size, u_int8_t rix)
{
	struct sample_node *sn = ATH_NODE_SAMPLE(an);
	int rateCode = -1;
	int size_bin = 0;
	int ndx = 0;

	size_bin = size_to_bin(frame_size);
	ndx = sn->current_rate[size_bin]; /* retry at the current bit-rate */
	
	if (!sn->stats[size_bin][ndx].packets_acked)
		ndx = 0;  /* use the lowest bit-rate */

	if (shortPreamble)
		rateCode = sn->rates[ndx].shortPreambleRateCode;
	else
		rateCode = sn->rates[ndx].rateCode;
	ath_hal_setupxtxdesc(sc->sc_ah, ds
			     , rateCode, 3	        /* series 1 */
			     , sn->rates[0].rateCode, 3	/* series 2 */
			     , 0, 0	                /* series 3 */
			     );
}
EXPORT_SYMBOL(ath_rate_setupxtxdesc);

static void 
update_stats(struct ath_softc *sc, struct ath_node *an, 
	int frame_size,
	int ndx0, int tries0,
	int ndx1, int tries1,
	int ndx2, int tries2,
	int ndx3, int tries3,
	int short_tries, int tries, int status)
{
	const HAL_RATE_TABLE *rt = sc->sc_currates;
	struct sample_node *sn = ATH_NODE_SAMPLE(an);
	struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
	int tt = 0;
	int tries_so_far = 0;
	int size_bin = 0;
	int size = 0;
	int rate = 0;

	size_bin = size_to_bin(frame_size);
	size = bin_to_size(size_bin);
	rate = sn->rates[ndx0].rate;

	if (!rt->info[ndx0].rateKbps) {
		/* 
		 * sometimes we get feedback back for packets we didn't send. 
		 * just ignore these packets.
		 */
		return;
	}
	tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx0].rix, 
		short_tries-1, 
		MIN(tries0, tries) - 1);
	tries_so_far += tries0;
	if (tries1 && tries0 < tries) {
		tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx1].rix, 
			short_tries - 1, 
			MIN(tries1 + tries_so_far, tries) - tries_so_far - 1);
	}
	tries_so_far += tries1;

	if (tries2 && tries0 + tries1 < tries) {
		tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx2].rix, 
			short_tries - 1,
			MIN(tries2 + tries_so_far, tries) - tries_so_far - 1);
	}

	tries_so_far += tries2;

	if (tries3 && tries0 + tries1 + tries2 < tries) {
		tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx3].rix, 
			short_tries - 1, 
			MIN(tries3 + tries_so_far, tries) - tries_so_far - 1);
	}
	
	if (sn->stats[size_bin][ndx0].total_packets < (100 / (100 - ssc->ath_smoothing_rate))) {
		/* just average the first few packets */
		int avg_tx = sn->stats[size_bin][ndx0].average_tx_time;
		int packets = sn->stats[size_bin][ndx0].total_packets;
		sn->stats[size_bin][ndx0].average_tx_time =
			(tt + (avg_tx * packets)) / (packets + 1);
	} else {
		/* use a ewma */
		sn->stats[size_bin][ndx0].average_tx_time = 
			((sn->stats[size_bin][ndx0].average_tx_time * ssc->ath_smoothing_rate) + 
			 (tt * (100 - ssc->ath_smoothing_rate))) / 100;
	}
	
	if (status) {
		int y;
		sn->stats[size_bin][ndx0].successive_failures++;
		for (y = size_bin+1; y < NUM_PACKET_SIZE_BINS; y++) {
			/* also say larger packets failed since we
			 * assume if a small packet fails at a lower
			 * bit-rate then a larger one will also.
			 */
			sn->stats[y][ndx0].successive_failures++;
			sn->stats[y][ndx0].last_tx = jiffies;
			sn->stats[y][ndx0].tries += tries;
			sn->stats[y][ndx0].total_packets++;
		}
	} else {
		sn->stats[size_bin][ndx0].packets_acked++;
		sn->stats[size_bin][ndx0].successive_failures = 0;
	}
	sn->stats[size_bin][ndx0].tries += tries;
	sn->stats[size_bin][ndx0].last_tx = jiffies;
	sn->stats[size_bin][ndx0].total_packets++;


	if (ndx0 == sn->current_sample_ndx[size_bin]) {
		DPRINTF(sc, "%s: %s size %d sample rate %d tries (%d/%d) tt %d avg_tt (%d/%d) status %d\n", 
			dev_info, ether_sprintf(an->an_node.ni_macaddr), 
			size, rate, short_tries, tries, tt, 
			sn->stats[size_bin][ndx0].average_tx_time,
			sn->stats[size_bin][ndx0].perfect_tx_time,
			status);
		sn->sample_tt[size_bin] = tt;
		sn->current_sample_ndx[size_bin] = -1;
	}
}

void
ath_rate_tx_complete(struct ath_softc *sc,
	struct ath_node *an, const struct ath_desc *ds)
{
	struct sample_node *sn = ATH_NODE_SAMPLE(an);
	struct ieee80211com *ic = &sc->sc_ic;
	const struct ar5212_desc *ads = (const struct ar5212_desc *)&ds->ds_ctl0;
	int final_rate = 0;
	int short_tries = 0;
	int long_tries = 0;
	int ndx = -1;
	int frame_size = 0;
	int mrr;

	final_rate = sc->sc_hwmap[ds->ds_txstat.ts_rate &~ HAL_TXSTAT_ALTRATE].ieeerate;
	short_tries = ds->ds_txstat.ts_shortretry + 1;
	long_tries = ds->ds_txstat.ts_longretry + 1;
	frame_size = ds->ds_ctl0 & 0x0fff; /* low-order 12 bits of ds_ctl0 */

	if (frame_size == 0)
		frame_size = 1500;

	if (sn->num_rates <= 0) {
		DPRINTF(sc, "%s: %s %s no rates yet\n", dev_info, 
			ether_sprintf(an->an_node.ni_macaddr), __func__);
		return;
	}

	mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT) && ENABLE_MRR;


	if (sc->sc_mrretry && ds->ds_txstat.ts_status) {
		/* this packet failed */
		DPRINTF(sc, "%s: %s size %d rate/try %d/%d %d/%d %d/%d %d/%d status %s retries (%d/%d)\n", 
			dev_info,
			ether_sprintf(an->an_node.ni_macaddr),
			bin_to_size(size_to_bin(frame_size)),
			sc->sc_hwmap[ads->xmit_rate0].ieeerate, ads->xmit_tries0,
			sc->sc_hwmap[ads->xmit_rate1].ieeerate, ads->xmit_tries1,
			sc->sc_hwmap[ads->xmit_rate2].ieeerate, ads->xmit_tries2,
			sc->sc_hwmap[ads->xmit_rate3].ieeerate, ads->xmit_tries3,
			ds->ds_txstat.ts_status ? "FAIL" : "OK",
			short_tries, 
			long_tries);
	}


	if (!mrr || !(ds->ds_txstat.ts_rate & HAL_TXSTAT_ALTRATE)) {
		/* only one rate was used */
		ndx = rate_to_ndx(sn, final_rate);
		if (ndx >= 0 && ndx < sn->num_rates) {
			update_stats(sc, an, frame_size, 
				ndx, long_tries,
				0, 0,
				0, 0,
				0, 0,
				short_tries, long_tries, ds->ds_txstat.ts_status);
		}
	} else {
		int rate0, tries0, ndx0;
		int rate1, tries1, ndx1;
		int rate2, tries2, ndx2;
		int rate3, tries3, ndx3;
		int finalTSIdx = ads->final_ts_index;

		/*
		 * Process intermediate rates that failed.
		 */

		rate0 = sc->sc_hwmap[ads->xmit_rate0].ieeerate;
		tries0 = ads->xmit_tries0;
		ndx0 = rate_to_ndx(sn, rate0);
		
		rate1 = sc->sc_hwmap[ads->xmit_rate1].ieeerate;
		tries1 = ads->xmit_tries1;
		ndx1 = rate_to_ndx(sn, rate1);
		
		rate2 = sc->sc_hwmap[ads->xmit_rate2].ieeerate;
		tries2 = ads->xmit_tries2;
		ndx2 = rate_to_ndx(sn, rate2);
		
		rate3 = sc->sc_hwmap[ads->xmit_rate3].ieeerate;
		tries3 = ads->xmit_tries3;
		ndx3 = rate_to_ndx(sn, rate3);
		
#if 0
		DPRINTF(sc, "%s: %s size %d finaltsidx %d tries %d status %d rate/try %d/%d %d/%d %d/%d %d/%d\n", 
			dev_info, ether_sprintf(an->an_node.ni_macaddr),
			bin_to_size(size_to_bin(frame_size)),
			finalTSIdx,
			long_tries, 
			ds->ds_txstat.ts_status,
			rate0, tries0,
			rate1, tries1,
			rate2, tries2,
			rate3, tries3);
#endif

		if (tries0)
			update_stats(sc, an, frame_size,