#define IWL_NUMBER_TRY 1
#define IWL_HT_NUMBER_TRY 3
-#define IWL_RATE_MAX_WINDOW 62
-#define IWL_RATE_HIGH_TH 10880
-#define IWL_RATE_MIN_FAILURE_TH 6
-#define IWL_RATE_MIN_SUCCESS_TH 8
-#define IWL_RATE_DECREASE_TH 1920
-#define IWL_RATE_INCREASE_TH 8960
-#define IWL_RATE_SCALE_FLUSH_INTVL (2*HZ) /*2 seconds */
+#define IWL_RATE_MAX_WINDOW 62 /* # tx in history window */
+#define IWL_RATE_MIN_FAILURE_TH 6 /* min failures to calc tpt */
+#define IWL_RATE_MIN_SUCCESS_TH 8 /* min successes to calc tpt */
+
+/* max time to accum history 2 seconds */
+#define IWL_RATE_SCALE_FLUSH_INTVL (2*HZ)
static u8 rs_ht_to_legacy[] = {
IWL_RATE_6M_INDEX, IWL_RATE_6M_INDEX,
u32 rate_n_flags;
} __attribute__ ((packed));
+/**
+ * struct iwl4965_rate_scale_data -- tx success history for one rate
+ */
struct iwl4965_rate_scale_data {
- u64 data;
- s32 success_counter;
- s32 success_ratio;
- s32 counter;
- s32 average_tpt;
+ u64 data; /* bitmap of successful frames */
+ s32 success_counter; /* number of frames successful */
+ s32 success_ratio; /* per-cent * 128 */
+ s32 counter; /* number of frames attempted */
+ s32 average_tpt; /* success ratio * expected throughput */
unsigned long stamp;
};
+/**
+ * struct iwl4965_scale_tbl_info -- tx params and success history for all rates
+ *
+ * There are two of these in struct iwl_rate_scale_priv,
+ * one for "active", and one for "search".
+ */
struct iwl4965_scale_tbl_info {
enum iwl4965_table_type lq_type;
enum iwl4965_antenna_type antenna_type;
- u8 is_SGI;
- u8 is_fat;
- u8 is_dup;
- u8 action;
- s32 *expected_tpt;
- struct iwl4965_rate current_rate;
- struct iwl4965_rate_scale_data win[IWL_RATE_COUNT];
+ u8 is_SGI; /* 1 = short guard interval */
+ u8 is_fat; /* 1 = 40 MHz channel width */
+ u8 is_dup; /* 1 = duplicated data streams */
+ u8 action; /* change modulation; IWL_[LEGACY/SISO/MIMO]_SWITCH_* */
+ s32 *expected_tpt; /* throughput metrics; expected_tpt_G, etc. */
+ struct iwl4965_rate current_rate; /* rate_n_flags, uCode API format */
+ struct iwl4965_rate_scale_data win[IWL_RATE_COUNT]; /* rate histories */
};
+/**
+ * struct iwl_rate_scale_priv -- driver's rate scaling private structure
+ *
+ * Pointer to this gets passed back and forth between driver and mac80211.
+ */
struct iwl4965_rate_scale_priv {
- u8 active_tbl;
- u8 enable_counter;
- u8 stay_in_tbl;
- u8 search_better_tbl;
+ u8 active_tbl; /* index of active table, range 0-1 */
+ u8 enable_counter; /* indicates HT mode */
+ u8 stay_in_tbl; /* 1: disallow, 0: allow search for new mode */
+ u8 search_better_tbl; /* 1: currently trying alternate mode */
s32 last_tpt;
+
+ /* The following determine when to search for a new mode */
u32 table_count_limit;
- u32 max_failure_limit;
- u32 max_success_limit;
+ u32 max_failure_limit; /* # failed frames before new search */
+ u32 max_success_limit; /* # successful frames before new search */
u32 table_count;
- u32 total_failed;
- u32 total_success;
- u32 flush_timer;
- u8 action_counter;
+ u32 total_failed; /* total failed frames, any/all rates */
+ u32 total_success; /* total successful frames, any/all rates */
+ u32 flush_timer; /* time staying in mode before new search */
+
+ u8 action_counter; /* # mode-switch actions tried */
u8 antenna;
u8 valid_antenna;
u8 is_green;
u8 is_dup;
u8 phymode;
u8 ibss_sta_added;
+
+ /* The following are bitmaps of rates; IWL_RATE_6M_MASK, etc. */
u32 supp_rates;
u16 active_rate;
u16 active_siso_rate;
u16 active_mimo_rate;
u16 active_rate_basic;
+
struct iwl4965_link_quality_cmd lq;
- struct iwl4965_scale_tbl_info lq_info[LQ_SIZE];
+ struct iwl4965_scale_tbl_info lq_info[LQ_SIZE]; /* "active", "search" */
#ifdef CONFIG_MAC80211_DEBUGFS
struct dentry *rs_sta_dbgfs_scale_table_file;
struct dentry *rs_sta_dbgfs_stats_table_file;
struct iwl4965_rate *mcs, int index)
{}
#endif
+
+/*
+ * Expected throughput metrics for following rates:
+ * 1, 2, 5.5, 11, 6, 9, 12, 18, 24, 36, 48, 54, 60 MBits
+ * "G" is the only table that supports CCK (the first 4 rates).
+ */
static s32 expected_tpt_A[IWL_RATE_COUNT] = {
0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186, 186
};
window->stamp = 0;
}
+/**
+ * rs_collect_tx_data - Update the success/failure sliding window
+ *
+ * We keep a sliding window of the last 62 packets transmitted
+ * at this rate. window->data contains the bitmask of successful
+ * packets.
+ */
static int rs_collect_tx_data(struct iwl4965_rate_scale_data *windows,
int scale_index, s32 tpt, u32 status)
{
if (scale_index < 0 || scale_index >= IWL_RATE_COUNT)
return -EINVAL;
+ /* Select data for current tx bit rate */
window = &(windows[scale_index]);
+ /*
+ * Keep track of only the latest 62 tx frame attempts in this rate's
+ * history window; anything older isn't really relevant any more.
+ * If we have filled up the sliding window, drop the oldest attempt;
+ * if the oldest attempt (highest bit in bitmap) shows "success",
+ * subtract "1" from the success counter (this is the main reason
+ * we keep these bitmaps!).
+ */
if (window->counter >= win_size) {
-
window->counter = win_size - 1;
mask = 1;
mask = (mask << (win_size - 1));
}
}
+ /* Increment frames-attempted counter */
window->counter = window->counter + 1;
+
+ /* Shift bitmap by one frame (throw away oldest history),
+ * OR in "1", and increment "success" if this frame was successful. */
mask = window->data;
window->data = (mask << 1);
if (status != 0) {
window->data |= 0x1;
}
+ /* Calculate current success ratio, avoid divide-by-0! */
if (window->counter > 0)
window->success_ratio = 128 * (100 * window->success_counter)
/ window->counter;
fail_count = window->counter - window->success_counter;
+ /* Calculate average throughput, if we have enough history. */
if ((fail_count >= IWL_RATE_MIN_FAILURE_TH) ||
(window->success_counter >= IWL_RATE_MIN_SUCCESS_TH))
window->average_tpt = (window->success_ratio * tpt + 64) / 128;
else
window->average_tpt = IWL_INVALID_VALUE;
+ /* Tag this window as having been updated */
window->stamp = jiffies;
return 0;
}
+/*
+ * Fill uCode API rate_n_flags field, based on "search" or "active" table.
+ */
static void rs_mcs_from_tbl(struct iwl4965_rate *mcs_rate,
struct iwl4965_scale_tbl_info *tbl,
int index, u8 use_green)
}
}
+/*
+ * Interpret uCode API's rate_n_flags format,
+ * fill "search" or "active" tx mode table.
+ */
static int rs_get_tbl_info_from_mcs(const struct iwl4965_rate *mcs_rate,
int phymode, struct iwl4965_scale_tbl_info *tbl,
int *rate_idx)
*rate_idx = -1;
return -EINVAL;
}
- tbl->is_SGI = 0;
+ tbl->is_SGI = 0; /* default legacy setup */
tbl->is_fat = 0;
tbl->is_dup = 0;
- tbl->antenna_type = ANT_BOTH;
+ tbl->antenna_type = ANT_BOTH; /* default MIMO setup */
+ /* legacy rate format */
if (!(mcs_rate->rate_n_flags & RATE_MCS_HT_MSK)) {
ant_msk = (mcs_rate->rate_n_flags & RATE_MCS_ANT_AB_MSK);
}
*rate_idx = index;
+ /* HT rate format, SISO (might be 20 MHz legacy or 40 MHz fat width) */
} else if (iwl4965_rate_get_rate(mcs_rate->rate_n_flags)
<= IWL_RATE_SISO_60M_PLCP) {
tbl->lq_type = LQ_SISO;
tbl->is_dup = 1;
*rate_idx = index;
+
+ /* HT rate format, MIMO (might be 20 MHz legacy or 40 MHz fat width) */
} else {
tbl->lq_type = LQ_MIMO;
if (mcs_rate->rate_n_flags & RATE_MCS_SGI_MSK)
rs_get_supported_rates(lq_data, NULL, tbl->lq_type, &rate_mask);
- /* mask with station rate restriction */
+ /* Mask with station rate restriction */
if (is_legacy(tbl->lq_type)) {
+ /* supp_rates has no CCK bits in A mode */
if (lq_data->phymode == (u8) MODE_IEEE80211A)
rate_mask = (u16)(rate_mask &
(lq_data->supp_rates << IWL_FIRST_OFDM_RATE));
rate_mask = (u16)(rate_mask & lq_data->supp_rates);
}
- /* if we did switched from HT to legacy check current rate */
+ /* If we switched from HT to legacy, check current rate */
if (switch_to_legacy && (rate_mask & (1 << scale_index))) {
rs_mcs_from_tbl(mcs_rate, tbl, scale_index, is_green);
return;
rs_mcs_from_tbl(mcs_rate, tbl, scale_index, is_green);
}
+/*
+ * mac80211 sends us Tx status
+ */
static void rs_tx_status(void *priv_rate,
struct net_device *dev,
struct sk_buff *skb,
table = &lq->lq;
active_index = lq->active_tbl;
+ /* Get mac80211 antenna info */
lq->antenna = (lq->valid_antenna & local->hw.conf.antenna_sel_tx);
if (!lq->antenna)
lq->antenna = lq->valid_antenna;
+ /* Ignore mac80211 antenna info for now */
lq->antenna = lq->valid_antenna;
+
curr_tbl = &(lq->lq_info[active_index]);
search_tbl = &(lq->lq_info[(1 - active_index)]);
window = (struct iwl4965_rate_scale_data *)
return;
}
+ /*
+ * Ignore this Tx frame response if its initial rate doesn't match
+ * that of latest Link Quality command. There may be stragglers
+ * from a previous Link Quality command, but we're no longer interested
+ * in those; they're either from the "active" mode while we're trying
+ * to check "search" mode, or a prior "search" mode after we've moved
+ * to a new "search" mode (which might become the new "active" mode).
+ */
if (retries &&
(tx_mcs.rate_n_flags !=
le32_to_cpu(table->rs_table[0].rate_n_flags))) {
return;
}
+ /* Update frame history window with "failure" for each Tx retry. */
while (retries) {
+ /* Look up the rate and other info used for each tx attempt.
+ * Each tx attempt steps one entry deeper in the rate table. */
tx_mcs.rate_n_flags =
le32_to_cpu(table->rs_table[index].rate_n_flags);
rs_get_tbl_info_from_mcs(&tx_mcs, priv->phymode,
&tbl_type, &rs_index);
+ /* If type matches "search" table,
+ * add failure to "search" history */
if ((tbl_type.lq_type == search_tbl->lq_type) &&
(tbl_type.antenna_type == search_tbl->antenna_type) &&
(tbl_type.is_SGI == search_tbl->is_SGI)) {
tpt = search_tbl->expected_tpt[rs_index];
else
tpt = 0;
- rs_collect_tx_data(search_win,
- rs_index, tpt, 0);
+ rs_collect_tx_data(search_win, rs_index, tpt, 0);
+
+ /* Else if type matches "current/active" table,
+ * add failure to "current/active" history */
} else if ((tbl_type.lq_type == curr_tbl->lq_type) &&
(tbl_type.antenna_type == curr_tbl->antenna_type) &&
(tbl_type.is_SGI == curr_tbl->is_SGI)) {
tpt = 0;
rs_collect_tx_data(window, rs_index, tpt, 0);
}
+
+ /* If not searching for a new mode, increment failed counter
+ * ... this helps determine when to start searching again */
if (lq->stay_in_tbl)
lq->total_failed++;
--retries;
}
+ /*
+ * Find (by rate) the history window to update with final Tx attempt;
+ * if Tx was successful first try, use original rate,
+ * else look up the rate that was, finally, successful.
+ */
if (!tx_resp->retry_count)
tx_mcs.rate_n_flags = tx_resp->control.tx_rate;
else
rs_get_tbl_info_from_mcs(&tx_mcs, priv->phymode,
&tbl_type, &rs_index);
+ /* Update frame history window with "success" if Tx got ACKed ... */
if (tx_resp->flags & IEEE80211_TX_STATUS_ACK)
status = 1;
else
status = 0;
+ /* If type matches "search" table,
+ * add final tx status to "search" history */
if ((tbl_type.lq_type == search_tbl->lq_type) &&
(tbl_type.antenna_type == search_tbl->antenna_type) &&
(tbl_type.is_SGI == search_tbl->is_SGI)) {
tpt = 0;
rs_collect_tx_data(search_win,
rs_index, tpt, status);
+
+ /* Else if type matches "current/active" table,
+ * add final tx status to "current/active" history */
} else if ((tbl_type.lq_type == curr_tbl->lq_type) &&
(tbl_type.antenna_type == curr_tbl->antenna_type) &&
(tbl_type.is_SGI == curr_tbl->is_SGI)) {
rs_collect_tx_data(window, rs_index, tpt, status);
}
+ /* If not searching for new mode, increment success/failed counter
+ * ... these help determine when to start searching again */
if (lq->stay_in_tbl) {
if (status)
lq->total_success++;
lq->total_failed++;
}
+ /* See if there's a better rate or modulation mode to try. */
rs_rate_scale_perform(priv, dev, hdr, sta);
sta_info_put(sta);
return;
return 0;
}
+/*
+ * Begin a period of staying with a selected modulation mode.
+ * Set "stay_in_tbl" flag to prevent any mode switches.
+ * Set frame tx success limits according to legacy vs. high-throughput,
+ * and reset overall (spanning all rates) tx success history statistics.
+ * These control how long we stay using same modulation mode before
+ * searching for a new mode.
+ */
static void rs_set_stay_in_table(u8 is_legacy,
struct iwl4965_rate_scale_priv *lq_data)
{
IWL_DEBUG_HT("we are staying in the same table\n");
- lq_data->stay_in_tbl = 1;
+ lq_data->stay_in_tbl = 1; /* only place this gets set */
if (is_legacy) {
lq_data->table_count_limit = IWL_LEGACY_TABLE_COUNT;
lq_data->max_failure_limit = IWL_LEGACY_FAILURE_LIMIT;
lq_data->total_success = 0;
}
+/*
+ * Find correct throughput table for given mode of modulation
+ */
static void rs_get_expected_tpt_table(struct iwl4965_rate_scale_priv *lq_data,
struct iwl4965_scale_tbl_info *tbl)
{
}
#ifdef CONFIG_IWL4965_HT
+/*
+ * Find starting rate for new "search" high-throughput mode of modulation.
+ * Goal is to find lowest expected rate (under perfect conditions) that is
+ * above the current measured throughput of "active" mode, to give new mode
+ * a fair chance to prove itself without too many challenges.
+ *
+ * This gets called when transitioning to more aggressive modulation
+ * (i.e. legacy to SISO or MIMO, or SISO to MIMO), as well as less aggressive
+ * (i.e. MIMO to SISO). When moving to MIMO, bit rate will typically need
+ * to decrease to match "active" throughput. When moving from MIMO to SISO,
+ * bit rate will typically need to increase, but not if performance was bad.
+ */
static s32 rs_get_best_rate(struct iwl4965_priv *priv,
struct iwl4965_rate_scale_priv *lq_data,
- struct iwl4965_scale_tbl_info *tbl,
+ struct iwl4965_scale_tbl_info *tbl, /* "search" */
u16 rate_mask, s8 index, s8 rate)
{
+ /* "active" values */
struct iwl4965_scale_tbl_info *active_tbl =
&(lq_data->lq_info[lq_data->active_tbl]);
- s32 new_rate, high, low, start_hi;
s32 active_sr = active_tbl->win[index].success_ratio;
- s32 *tpt_tbl = tbl->expected_tpt;
s32 active_tpt = active_tbl->expected_tpt[index];
+
+ /* expected "search" throughput */
+ s32 *tpt_tbl = tbl->expected_tpt;
+
+ s32 new_rate, high, low, start_hi;
u16 high_low;
new_rate = high = low = start_hi = IWL_RATE_INVALID;
low = high_low & 0xff;
high = (high_low >> 8) & 0xff;
+ /*
+ * Lower the "search" bit rate, to give new "search" mode
+ * approximately the same throughput as "active" if:
+ *
+ * 1) "Active" mode has been working modestly well (but not
+ * great), and expected "search" throughput (under perfect
+ * conditions) at candidate rate is above the actual
+ * measured "active" throughput (but less than expected
+ * "active" throughput under perfect conditions).
+ * OR
+ * 2) "Active" mode has been working perfectly or very well
+ * and expected "search" throughput (under perfect
+ * conditions) at candidate rate is above expected
+ * "active" throughput (under perfect conditions).
+ */
if ((((100 * tpt_tbl[rate]) > lq_data->last_tpt) &&
((active_sr > IWL_RATE_DECREASE_TH) &&
(active_sr <= IWL_RATE_HIGH_TH) &&
((active_sr >= IWL_RATE_SCALE_SWITCH) &&
(tpt_tbl[rate] > active_tpt))) {
+ /* (2nd or later pass)
+ * If we've already tried to raise the rate, and are
+ * now trying to lower it, use the higher rate. */
if (start_hi != IWL_RATE_INVALID) {
new_rate = start_hi;
break;
}
+
new_rate = rate;
+
+ /* Loop again with lower rate */
if (low != IWL_RATE_INVALID)
rate = low;
+
+ /* Lower rate not available, use the original */
else
break;
+
+ /* Else try to raise the "search" rate to match "active" */
} else {
+ /* (2nd or later pass)
+ * If we've already tried to lower the rate, and are
+ * now trying to raise it, use the lower rate. */
if (new_rate != IWL_RATE_INVALID)
break;
+
+ /* Loop again with higher rate */
else if (high != IWL_RATE_INVALID) {
start_hi = high;
rate = high;
+
+ /* Higher rate not available, use the original */
} else {
new_rate = rate;
break;
return (rs_is_ant_connected(valid_antenna, ANT_BOTH));
}
+/*
+ * Set up search table for MIMO
+ */
static int rs_switch_to_mimo(struct iwl4965_priv *priv,
struct iwl4965_rate_scale_priv *lq_data,
struct iwl4965_scale_tbl_info *tbl, int index)
if (priv->current_assoc_ht.tx_mimo_ps_mode == IWL_MIMO_PS_STATIC)
return -1;
+ /* Need both Tx chains/antennas to support MIMO */
if (!rs_is_both_ant_supp(lq_data->antenna))
return -1;
#endif /*CONFIG_IWL4965_HT */
}
+/*
+ * Set up search table for SISO
+ */
static int rs_switch_to_siso(struct iwl4965_priv *priv,
struct iwl4965_rate_scale_priv *lq_data,
struct iwl4965_scale_tbl_info *tbl, int index)
#endif /*CONFIG_IWL4965_HT */
}
+/*
+ * Try to switch to new modulation mode from legacy
+ */
static int rs_move_legacy_other(struct iwl4965_priv *priv,
struct iwl4965_rate_scale_priv *lq_data,
int index)
search_tbl->lq_type = LQ_NONE;
lq_data->action_counter++;
+
+ /* Don't change antenna if success has been great */
if (window->success_ratio >= IWL_RS_GOOD_RATIO)
break;
+
+ /* Don't change antenna if other one is not connected */
if (!rs_is_other_ant_connected(lq_data->antenna,
tbl->antenna_type))
break;
+ /* Set up search table to try other antenna */
memcpy(search_tbl, tbl, sz);
rs_toggle_antenna(&(search_tbl->current_rate),
case IWL_LEGACY_SWITCH_SISO:
IWL_DEBUG_HT("LQ: Legacy switch to SISO\n");
+
+ /* Set up search table to try SISO */
memcpy(search_tbl, tbl, sz);
search_tbl->lq_type = LQ_SISO;
search_tbl->is_SGI = 0;
break;
case IWL_LEGACY_SWITCH_MIMO:
IWL_DEBUG_HT("LQ: Legacy switch MIMO\n");
+
+ /* Set up search table to try MIMO */
memcpy(search_tbl, tbl, sz);
search_tbl->lq_type = LQ_MIMO;
search_tbl->is_SGI = 0;
}
+/*
+ * Try to switch to new modulation mode from SISO
+ */
static int rs_move_siso_to_other(struct iwl4965_priv *priv,
struct iwl4965_rate_scale_priv *lq_data,
int index)
return 0;
}
+/*
+ * Try to switch to new modulation mode from MIMO
+ */
static int rs_move_mimo_to_other(struct iwl4965_priv *priv,
struct iwl4965_rate_scale_priv *lq_data,
int index)
case IWL_MIMO_SWITCH_ANTENNA_A:
case IWL_MIMO_SWITCH_ANTENNA_B:
IWL_DEBUG_HT("LQ: MIMO SWITCH TO SISO\n");
+
+ /* Set up new search table for SISO */
memcpy(search_tbl, tbl, sz);
search_tbl->lq_type = LQ_SISO;
search_tbl->is_SGI = 0;
case IWL_MIMO_SWITCH_GI:
IWL_DEBUG_HT("LQ: MIMO SWITCH TO GI\n");
+
+ /* Set up new search table for MIMO */
memcpy(search_tbl, tbl, sz);
search_tbl->lq_type = LQ_MIMO;
search_tbl->antenna_type = ANT_BOTH;
else
search_tbl->is_SGI = 1;
lq_data->search_better_tbl = 1;
+
+ /*
+ * If active table already uses the fastest possible
+ * modulation (dual stream with short guard interval),
+ * and it's working well, there's no need to look
+ * for a better type of modulation!
+ */
if ((tbl->lq_type == LQ_MIMO) &&
(tbl->is_SGI)) {
s32 tpt = lq_data->last_tpt / 100;
}
+/*
+ * Check whether we should continue using same modulation mode, or
+ * begin search for a new mode, based on:
+ * 1) # tx successes or failures while using this mode
+ * 2) # times calling this function
+ * 3) elapsed time in this mode (not used, for now)
+ */
static void rs_stay_in_table(struct iwl4965_rate_scale_priv *lq_data)
{
struct iwl4965_scale_tbl_info *tbl;
tbl = &(lq_data->lq_info[active_tbl]);
+ /* If we've been disallowing search, see if we should now allow it */
if (lq_data->stay_in_tbl) {
+ /* Elapsed time using current modulation mode */
if (lq_data->flush_timer)
flush_interval_passed =
time_after(jiffies,
(unsigned long)(lq_data->flush_timer +
IWL_RATE_SCALE_FLUSH_INTVL));
+ /* For now, disable the elapsed time criterion */
flush_interval_passed = 0;
+
+ /*
+ * Check if we should allow search for new modulation mode.
+ * If many frames have failed or succeeded, or we've used
+ * this same modulation for a long time, allow search, and
+ * reset history stats that keep track of whether we should
+ * allow a new search. Also (below) reset all bitmaps and
+ * stats in active history.
+ */
if ((lq_data->total_failed > lq_data->max_failure_limit) ||
(lq_data->total_success > lq_data->max_success_limit) ||
((!lq_data->search_better_tbl) && (lq_data->flush_timer)
lq_data->total_failed,
lq_data->total_success,
flush_interval_passed);
- lq_data->stay_in_tbl = 0;
+
+ /* Allow search for new mode */
+ lq_data->stay_in_tbl = 0; /* only place reset */
lq_data->total_failed = 0;
lq_data->total_success = 0;
lq_data->flush_timer = 0;
+
+ /*
+ * Else if we've used this modulation mode enough repetitions
+ * (regardless of elapsed time or success/failure), reset
+ * history bitmaps and rate-specific stats for all rates in
+ * active table.
+ */
} else {
lq_data->table_count++;
if (lq_data->table_count >=
}
}
+ /* If transitioning to allow "search", reset all history
+ * bitmaps and stats in active table (this will become the new
+ * "search" table). */
if (!lq_data->stay_in_tbl) {
for (i = 0; i < IWL_RATE_COUNT; i++)
rs_rate_scale_clear_window(&(tbl->win[i]));
}
}
+/*
+ * Do rate scaling and search for new modulation mode.
+ */
static void rs_rate_scale_perform(struct iwl4965_priv *priv,
struct net_device *dev,
struct ieee80211_hdr *hdr,
}
lq_data = (struct iwl4965_rate_scale_priv *)sta->rate_ctrl_priv;
+ /*
+ * Select rate-scale / modulation-mode table to work with in
+ * the rest of this function: "search" if searching for better
+ * modulation mode, or "active" if doing rate scaling within a mode.
+ */
if (!lq_data->search_better_tbl)
active_tbl = lq_data->active_tbl;
else
tbl = &(lq_data->lq_info[active_tbl]);
is_green = lq_data->is_green;
+ /* current tx rate */
index = sta->last_txrate;
IWL_DEBUG_RATE("Rate scale index %d for type %d\n", index,
tbl->lq_type);
+ /* rates available for this association, and for modulation mode */
rs_get_supported_rates(lq_data, hdr, tbl->lq_type,
&rate_mask);
/* mask with station rate restriction */
if (is_legacy(tbl->lq_type)) {
if (lq_data->phymode == (u8) MODE_IEEE80211A)
+ /* supp_rates has no CCK bits in A mode */
rate_scale_index_msk = (u16) (rate_mask &
(lq_data->supp_rates << IWL_FIRST_OFDM_RATE));
else
if (!rate_scale_index_msk)
rate_scale_index_msk = rate_mask;
+ /* If current rate is no longer supported on current association,
+ * or user changed preferences for rates, find a new supported rate. */
if (index < 0 || !((1 << index) & rate_scale_index_msk)) {
index = IWL_INVALID_VALUE;
update_lq = 1;
- /* get the lowest available rate */
+ /* get the highest available rate */
for (i = 0; i <= IWL_RATE_COUNT; i++) {
if ((1 << i) & rate_scale_index_msk)
index = i;
}
}
+ /* Get expected throughput table and history window for current rate */
if (!tbl->expected_tpt)
rs_get_expected_tpt_table(lq_data, tbl);
window = &(tbl->win[index]);
+ /*
+ * If there is not enough history to calculate actual average
+ * throughput, keep analyzing results of more tx frames, without
+ * changing rate or mode (bypass most of the rest of this function).
+ * Set up new rate table in uCode only if old rate is not supported
+ * in current association (use new rate found above).
+ */
fail_count = window->counter - window->success_counter;
if (((fail_count < IWL_RATE_MIN_FAILURE_TH) &&
(window->success_counter < IWL_RATE_MIN_SUCCESS_TH))
IWL_DEBUG_RATE("LQ: still below TH succ %d total %d "
"for index %d\n",
window->success_counter, window->counter, index);
+
+ /* Can't calculate this yet; not enough history */
window->average_tpt = IWL_INVALID_VALUE;
+
+ /* Should we stay with this modulation mode,
+ * or search for a new one? */
rs_stay_in_table(lq_data);
+
+ /* Set up new rate table in uCode, if needed */
if (update_lq) {
rs_mcs_from_tbl(&mcs_rate, tbl, index, is_green);
rs_fill_link_cmd(lq_data, &mcs_rate, &lq_data->lq);
}
goto out;
+ /* Else we have enough samples; calculate estimate of
+ * actual average throughput */
} else
window->average_tpt = ((window->success_ratio *
tbl->expected_tpt[index] + 64) / 128);
+ /* If we are searching for better modulation mode, check success. */
if (lq_data->search_better_tbl) {
int success_limit = IWL_RATE_SCALE_SWITCH;
+ /* If good success, continue using the "search" mode;
+ * no need to send new link quality command, since we're
+ * continuing to use the setup that we've been trying. */
if ((window->success_ratio > success_limit) ||
(window->average_tpt > lq_data->last_tpt)) {
if (!is_legacy(tbl->lq_type)) {
lq_data->last_tpt);
lq_data->enable_counter = 1;
}
+ /* Swap tables; "search" becomes "active" */
lq_data->active_tbl = active_tbl;
current_tpt = window->average_tpt;
+
+ /* Else poor success; go back to mode in "active" table */
} else {
+ /* Nullify "search" table */
tbl->lq_type = LQ_NONE;
+
+ /* Revert to "active" table */
active_tbl = lq_data->active_tbl;
tbl = &(lq_data->lq_info[active_tbl]);
+ /* Revert to "active" rate and throughput info */
index = iwl4965_rate_index_from_plcp(
tbl->current_rate.rate_n_flags);
+ current_tpt = lq_data->last_tpt;
+ /* Need to set up a new rate table in uCode */
update_lq = 1;
- current_tpt = lq_data->last_tpt;
IWL_DEBUG_HT("XXY GO BACK TO OLD TABLE\n");
}
+
+ /* Either way, we've made a decision; modulation mode
+ * search is done, allow rate adjustment next time. */
lq_data->search_better_tbl = 0;
- done_search = 1;
+ done_search = 1; /* Don't switch modes below! */
goto lq_update;
}
+ /* (Else) not in search of better modulation mode, try for better
+ * starting rate, while staying in this mode. */
high_low = rs_get_adjacent_rate(index, rate_scale_index_msk,
tbl->lq_type);
low = high_low & 0xff;
high = (high_low >> 8) & 0xff;
+ /* Collect measured throughputs for current and adjacent rates */
current_tpt = window->average_tpt;
-
if (low != IWL_RATE_INVALID)
low_tpt = tbl->win[low].average_tpt;
-
if (high != IWL_RATE_INVALID)
high_tpt = tbl->win[high].average_tpt;
-
+ /* Assume rate increase */
scale_action = 1;
+ /* Too many failures, decrease rate */
if ((window->success_ratio <= IWL_RATE_DECREASE_TH) ||
(current_tpt == 0)) {
IWL_DEBUG_RATE("decrease rate because of low success_ratio\n");
scale_action = -1;
+
+ /* No throughput measured yet for adjacent rates; try increase. */
} else if ((low_tpt == IWL_INVALID_VALUE) &&
(high_tpt == IWL_INVALID_VALUE))
scale_action = 1;
+
+ /* Both adjacent throughputs are measured, but neither one has better
+ * throughput; we're using the best rate, don't change it! */
else if ((low_tpt != IWL_INVALID_VALUE) &&
(high_tpt != IWL_INVALID_VALUE) &&
(low_tpt < current_tpt) &&
(high_tpt < current_tpt))
scale_action = 0;
+
+ /* At least one adjacent rate's throughput is measured,
+ * and may have better performance. */
else {
+ /* Higher adjacent rate's throughput is measured */
if (high_tpt != IWL_INVALID_VALUE) {
+ /* Higher rate has better throughput */
if (high_tpt > current_tpt)
scale_action = 1;
else {
("decrease rate because of high tpt\n");
scale_action = -1;
}
+
+ /* Lower adjacent rate's throughput is measured */
} else if (low_tpt != IWL_INVALID_VALUE) {
+ /* Lower rate has better throughput */
if (low_tpt > current_tpt) {
IWL_DEBUG_RATE
("decrease rate because of low tpt\n");
}
}
+ /* Sanity check; asked for decrease, but success rate or throughput
+ * has been good at old rate. Don't change it. */
if (scale_action == -1) {
if ((low != IWL_RATE_INVALID) &&
((window->success_ratio > IWL_RATE_HIGH_TH) ||
(current_tpt > (100 * tbl->expected_tpt[low]))))
scale_action = 0;
+
+ /* Sanity check; asked for increase, but success rate has not been great
+ * even at old rate, higher rate will be worse. Don't change it. */
} else if ((scale_action == 1) &&
(window->success_ratio < IWL_RATE_INCREASE_TH))
scale_action = 0;
switch (scale_action) {
case -1:
+ /* Decrease starting rate, update uCode's rate table */
if (low != IWL_RATE_INVALID) {
update_lq = 1;
index = low;
}
break;
case 1:
+ /* Increase starting rate, update uCode's rate table */
if (high != IWL_RATE_INVALID) {
update_lq = 1;
index = high;
break;
case 0:
+ /* No change */
default:
break;
}
index, scale_action, low, high, tbl->lq_type);
lq_update:
+ /* Replace uCode's rate table for the destination station. */
if (update_lq) {
rs_mcs_from_tbl(&mcs_rate, tbl, index, is_green);
rs_fill_link_cmd(lq_data, &mcs_rate, &lq_data->lq);
rs_send_lq_cmd(priv, &lq_data->lq, CMD_ASYNC);
}
+
+ /* Should we stay with this modulation mode, or search for a new one? */
rs_stay_in_table(lq_data);
+ /*
+ * Search for new modulation mode if we're:
+ * 1) Not changing rates right now
+ * 2) Not just finishing up a search
+ * 3) Allowing a new search
+ */
if (!update_lq && !done_search && !lq_data->stay_in_tbl) {
+ /* Save current throughput to compare with "search" throughput*/
lq_data->last_tpt = current_tpt;
+ /* Select a new "search" modulation mode to try.
+ * If one is found, set up the new "search" table. */
if (is_legacy(tbl->lq_type))
rs_move_legacy_other(priv, lq_data, index);
else if (is_siso(tbl->lq_type))
else
rs_move_mimo_to_other(priv, lq_data, index);
+ /* If new "search" mode was selected, set up in uCode table */
if (lq_data->search_better_tbl) {
+ /* Access the "search" table, clear its history. */
tbl = &(lq_data->lq_info[(1 - lq_data->active_tbl)]);
for (i = 0; i < IWL_RATE_COUNT; i++)
rs_rate_scale_clear_window(&(tbl->win[i]));
+ /* Use new "search" start rate */
index = iwl4965_rate_index_from_plcp(
tbl->current_rate.rate_n_flags);
&lq_data->lq);
rs_send_lq_cmd(priv, &lq_data->lq, CMD_ASYNC);
}
- tbl1 = &(lq_data->lq_info[lq_data->active_tbl]);
+ /* If the "active" (non-search) mode was legacy,
+ * and we've tried switching antennas,
+ * but we haven't been able to try HT modes (not available),
+ * stay with best antenna legacy modulation for a while
+ * before next round of mode comparisons. */
+ tbl1 = &(lq_data->lq_info[lq_data->active_tbl]);
if (is_legacy(tbl1->lq_type) &&
#ifdef CONFIG_IWL4965_HT
!priv->current_assoc_ht.is_ht &&
rs_set_stay_in_table(1, lq_data);
}
+ /* If we're in an HT mode, and all 3 mode switch actions
+ * have been tried and compared, stay in this best modulation
+ * mode for a while before next round of mode comparisons. */
if (lq_data->enable_counter &&
(lq_data->action_counter >= IWL_ACTION_LIMIT)) {
#ifdef CONFIG_IWL4965_HT_AGG
+ /* If appropriate, set up aggregation! */
if ((lq_data->last_tpt > TID_AGG_TPT_THREHOLD) &&
(priv->lq_mngr.agg_ctrl.auto_agg)) {
priv->lq_mngr.agg_ctrl.tid_retry =
lq_data->action_counter = 0;
rs_set_stay_in_table(0, lq_data);
}
+
+ /*
+ * Else, don't search for a new modulation mode.
+ * Put new timestamp in stay-in-modulation-mode flush timer if:
+ * 1) Not changing rates right now
+ * 2) Not just finishing up a search
+ * 3) flush timer is empty
+ */
} else {
if ((!update_lq) && (!done_search) && (!lq_data->flush_timer))
lq_data->flush_timer = jiffies;
priv->assoc_station_added = 1;
}
+ /* Find highest tx rate supported by hardware and destination station */
for (i = 0; i < mode->num_rates; i++) {
if ((sta->supp_rates & BIT(i)) &&
(mode->rates[i].flags & IEEE80211_RATE_SUPPORTED))
sta->txrate = i;
}
sta->last_txrate = sta->txrate;
- /* For MODE_IEEE80211A mode cck rate are at end
- * rate table
- */
+ /* For MODE_IEEE80211A, cck rates are at end of rate table */
if (local->hw.conf.phymode == MODE_IEEE80211A)
sta->last_txrate += IWL_FIRST_OFDM_RATE;
crl->active_rate_basic = priv->active_rate_basic;
crl->phymode = priv->phymode;
#ifdef CONFIG_IWL4965_HT
+ /*
+ * active_siso_rate mask includes 9 MBits (bit 5), and CCK (bits 0-3),
+ * supp_rates[] does not; shift to convert format, force 9 MBits off.
+ */
crl->active_siso_rate = (priv->current_assoc_ht.supp_rates[0] << 1);
crl->active_siso_rate |= (priv->current_assoc_ht.supp_rates[0] & 0x1);
crl->active_siso_rate &= ~((u16)0x2);
crl->active_siso_rate = crl->active_siso_rate << IWL_FIRST_OFDM_RATE;
+ /* Same here */
crl->active_mimo_rate = (priv->current_assoc_ht.supp_rates[1] << 1);
crl->active_mimo_rate |= (priv->current_assoc_ht.supp_rates[1] & 0x1);
crl->active_mimo_rate &= ~((u16)0x2);
struct iwl4965_rate new_rate;
struct iwl4965_scale_tbl_info tbl_type = { 0 };
+ /* Override starting rate (index 0) if needed for debug purposes */
rs_dbgfs_set_mcs(lq_data, tx_mcs, index);
+ /* Interpret rate_n_flags */
rs_get_tbl_info_from_mcs(tx_mcs, lq_data->phymode,
&tbl_type, &rate_idx);
+ /* How many times should we repeat the initial rate? */
if (is_legacy(tbl_type.lq_type)) {
ant_toggle_count = 1;
repeat_rate = IWL_NUMBER_TRY;
lq_cmd->general_params.mimo_delimiter =
is_mimo(tbl_type.lq_type) ? 1 : 0;
+
+ /* Fill 1st table entry (index 0) */
lq_cmd->rs_table[index].rate_n_flags =
cpu_to_le32(tx_mcs->rate_n_flags);
new_rate.rate_n_flags = tx_mcs->rate_n_flags;
if (is_mimo(tbl_type.lq_type) || (tbl_type.antenna_type == ANT_MAIN))
- lq_cmd->general_params.single_stream_ant_msk = 1;
+ lq_cmd->general_params.single_stream_ant_msk
+ = LINK_QUAL_ANT_A_MSK;
else
- lq_cmd->general_params.single_stream_ant_msk = 2;
+ lq_cmd->general_params.single_stream_ant_msk
+ = LINK_QUAL_ANT_B_MSK;
index++;
repeat_rate--;
+ /* Fill rest of rate table */
while (index < LINK_QUAL_MAX_RETRY_NUM) {
+ /* Repeat initial/next rate.
+ * For legacy IWL_NUMBER_TRY == 1, this loop will not execute.
+ * For HT IWL_HT_NUMBER_TRY == 3, this executes twice. */
while (repeat_rate > 0 && (index < LINK_QUAL_MAX_RETRY_NUM)) {
if (is_legacy(tbl_type.lq_type)) {
if (ant_toggle_count <
}
}
+ /* Override next rate if needed for debug purposes */
rs_dbgfs_set_mcs(lq_data, &new_rate, index);
+
+ /* Fill next table entry */
lq_cmd->rs_table[index].rate_n_flags =
cpu_to_le32(new_rate.rate_n_flags);
repeat_rate--;
rs_get_tbl_info_from_mcs(&new_rate, lq_data->phymode, &tbl_type,
&rate_idx);
+ /* Indicate to uCode which entries might be MIMO.
+ * If initial rate was MIMO, this will finally end up
+ * as (IWL_HT_NUMBER_TRY * 2), after 2nd pass, otherwise 0. */
if (is_mimo(tbl_type.lq_type))
lq_cmd->general_params.mimo_delimiter = index;
+ /* Get next rate */
rs_get_lower_rate(lq_data, &tbl_type, rate_idx,
use_ht_possible, &new_rate);
+ /* How many times should we repeat the next rate? */
if (is_legacy(tbl_type.lq_type)) {
if (ant_toggle_count < NUM_TRY_BEFORE_ANTENNA_TOGGLE)
ant_toggle_count++;
} else
repeat_rate = IWL_HT_NUMBER_TRY;
+ /* Don't allow HT rates after next pass.
+ * rs_get_lower_rate() will change type to LQ_A or LQ_G. */
use_ht_possible = 0;
+ /* Override next rate if needed for debug purposes */
rs_dbgfs_set_mcs(lq_data, &new_rate, index);
+
+ /* Fill next table entry */
lq_cmd->rs_table[index].rate_n_flags =
cpu_to_le32(new_rate.rate_n_flags);
else
rs_priv->dbg_fixed.rate_n_flags = 0;
- rs_priv->active_rate = 0x0FFF;
- rs_priv->active_siso_rate = 0x1FD0;
- rs_priv->active_mimo_rate = 0x1FD0;
+ rs_priv->active_rate = 0x0FFF; /* 1 - 54 MBits, includes CCK */
+ rs_priv->active_siso_rate = 0x1FD0; /* 6 - 60 MBits, no 9, no CCK */
+ rs_priv->active_mimo_rate = 0x1FD0; /* 6 - 60 MBits, no 9, no CCK */
IWL_DEBUG_RATE("sta_id %d rate 0x%X\n",
rs_priv->lq.sta_id, rs_priv->dbg_fixed.rate_n_flags);
/* Display the average rate of all samples taken.
*
- * NOTE: We multiple # of samples by 2 since the IEEE measurement
+ * NOTE: We multiply # of samples by 2 since the IEEE measurement
* added from iwl4965_rates is actually 2X the rate */
if (samples)
count += sprintf(&buf[count],
projects / linux-2.6 / commitdiff