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iwlwifi: mvm: rs: fix and cleanup rs_get_rate_action 

Change the down/upscale decision logic a bit to be based
on different success ratio thresholds. This fixes the implementation
compared to the rate scale algorithm which was planned to yield
optimal results. Also fix a case where a lower rate wasn't explored
despite being a potential for better throughput.
While at it rewrite rs_get_rate_action to be more clear and clean.

Cc: <stable@vger.kernel.org> [3.14]
Signed-off-by: Eyal Shapira <eyalx.shapira@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
This commit is contained in:
Eyal Shapira 2014-04-06 02:42:18 +03:00 committed by Emmanuel Grumbach
parent 198266a3c1
commit e53839eb98
2 changed files with 65 additions and 73 deletions
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137
drivers/net/wireless/iwlwifi/mvm/rs.c
View File

@ -1658,87 +1658,78 @@ static enum rs_action rs_get_rate_action(struct iwl_mvm *mvm,
{
enum rs_action action = RS_ACTION_STAY;
/* Too many failures, decrease rate */
if ((sr <= RS_SR_FORCE_DECREASE) || (current_tpt == 0)) {
IWL_DEBUG_RATE(mvm,
"decrease rate because of low SR\n");
"Decrease rate because of low SR\n");
return RS_ACTION_DOWNSCALE;
}
if ((low_tpt == IWL_INVALID_VALUE) &&
(high_tpt == IWL_INVALID_VALUE) &&
(high != IWL_RATE_INVALID)) {
IWL_DEBUG_RATE(mvm,
"No data about high/low rates. Increase rate\n");
return RS_ACTION_UPSCALE;
}
if ((high_tpt == IWL_INVALID_VALUE) &&
(high != IWL_RATE_INVALID) &&
(low_tpt != IWL_INVALID_VALUE) &&
(low_tpt < current_tpt)) {
IWL_DEBUG_RATE(mvm,
"No data about high rate and low rate is worse. Increase rate\n");
return RS_ACTION_UPSCALE;
}
if ((high_tpt != IWL_INVALID_VALUE) &&
(high_tpt > current_tpt)) {
IWL_DEBUG_RATE(mvm,
"Higher rate is better. Increate rate\n");
return RS_ACTION_UPSCALE;
}
if ((low_tpt != IWL_INVALID_VALUE) &&
(high_tpt != IWL_INVALID_VALUE) &&
(low_tpt < current_tpt) &&
(high_tpt < current_tpt)) {
IWL_DEBUG_RATE(mvm,
"Both high and low are worse. Maintain rate\n");
return RS_ACTION_STAY;
}
if ((low_tpt != IWL_INVALID_VALUE) &&
(low_tpt > current_tpt)) {
IWL_DEBUG_RATE(mvm,
"Lower rate is better\n");
action = RS_ACTION_DOWNSCALE;
/* No throughput measured yet for adjacent rates; try increase. */
} else if ((low_tpt == IWL_INVALID_VALUE) &&
(high_tpt == IWL_INVALID_VALUE)) {
if (high != IWL_RATE_INVALID && sr >= IWL_RATE_INCREASE_TH) {
goto out;
}
if ((low_tpt == IWL_INVALID_VALUE) &&
(low != IWL_RATE_INVALID)) {
IWL_DEBUG_RATE(mvm,
"No data about lower rate\n");
action = RS_ACTION_DOWNSCALE;
goto out;
}
IWL_DEBUG_RATE(mvm, "Maintain rate\n");
out:
if ((action == RS_ACTION_DOWNSCALE) && (low != IWL_RATE_INVALID)) {
if (sr >= RS_SR_NO_DECREASE) {
IWL_DEBUG_RATE(mvm,
"Good SR and no high rate measurement. "
"Increase rate\n");
action = RS_ACTION_UPSCALE;
} else if (low != IWL_RATE_INVALID) {
IWL_DEBUG_RATE(mvm,
"Remain in current rate\n");
"SR is above NO DECREASE. Avoid downscale\n");
action = RS_ACTION_STAY;
} else if (current_tpt > (100 * tbl->expected_tpt[low])) {
IWL_DEBUG_RATE(mvm,
"Current TPT is higher than max expected in low rate. Avoid downscale\n");
action = RS_ACTION_STAY;
} else {
IWL_DEBUG_RATE(mvm, "Decrease rate\n");
}
}
/* 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)) {
IWL_DEBUG_RATE(mvm,
"Both high and low are worse. "
"Maintain rate\n");
action = RS_ACTION_STAY;
}
/* 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 &&
sr >= IWL_RATE_INCREASE_TH) {
IWL_DEBUG_RATE(mvm,
"Higher rate is better and good "
"SR. Increate rate\n");
action = RS_ACTION_UPSCALE;
} else {
IWL_DEBUG_RATE(mvm,
"Higher rate isn't better OR "
"no good SR. Maintain rate\n");
action = RS_ACTION_STAY;
}
/* 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(mvm,
"Lower rate is better. "
"Decrease rate\n");
action = RS_ACTION_DOWNSCALE;
} else if (sr >= IWL_RATE_INCREASE_TH) {
IWL_DEBUG_RATE(mvm,
"Lower rate isn't better and "
"good SR. Increase rate\n");
action = RS_ACTION_UPSCALE;
}
}
}
/* Sanity check; asked for decrease, but success rate or throughput
* has been good at old rate. Don't change it.
*/
if ((action == RS_ACTION_DOWNSCALE) && (low != IWL_RATE_INVALID) &&
((sr > IWL_RATE_HIGH_TH) ||
(current_tpt > (100 * tbl->expected_tpt[low])))) {
IWL_DEBUG_RATE(mvm,
"Sanity check failed. Maintain rate\n");
action = RS_ACTION_STAY;
}
return action;
}

1
drivers/net/wireless/iwlwifi/mvm/rs.h
View File

@ -156,6 +156,7 @@ enum {
#define IWL_RATE_HIGH_TH 10880 /* 85% */
#define IWL_RATE_INCREASE_TH 6400 /* 50% */
#define RS_SR_FORCE_DECREASE 1920 /* 15% */
#define RS_SR_NO_DECREASE 10880 /* 85% */
#define LINK_QUAL_AGG_TIME_LIMIT_DEF (4000) /* 4 milliseconds */
#define LINK_QUAL_AGG_TIME_LIMIT_MAX (8000)