From ed21a384bbd2b011289dd1b5cab7eebc7ebeda11 Mon Sep 17 00:00:00 2001 From: Eyal Shapira Date: Mon, 21 Sep 2015 20:03:22 +0300 Subject: [PATCH] iwlwifi: mvm: rs: fix success ratio comparison in rs_get_best_rate success_ratio is actually 128 * SR in percentage while IWL_MVM_RS_SR_NO_DECREASE is 85%. Fix this by using RS_PERCENT(). This bug caused the if branch to be always executed. This in turn led to always selecting a rate, following a column switch, in which the expected throughput would exceed the best expected current throughput. In some scenarios where the success ratio isn't >85% such a rate could be too aggressive leading us to avoid the new column. This has the potential of causing sub optimal performance. Reported-by: Moshe Harel Signed-off-by: Eyal Shapira Signed-off-by: Luca Coelho --- drivers/net/wireless/iwlwifi/mvm/rs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/mvm/rs.c b/drivers/net/wireless/iwlwifi/mvm/rs.c index 2bf2a0895723..435e1e40edb8 100644 --- a/drivers/net/wireless/iwlwifi/mvm/rs.c +++ b/drivers/net/wireless/iwlwifi/mvm/rs.c @@ -1527,7 +1527,7 @@ static s32 rs_get_best_rate(struct iwl_mvm *mvm, u32 target_tpt; int rate_idx; - if (success_ratio > IWL_MVM_RS_SR_NO_DECREASE) { + if (success_ratio >= RS_PERCENT(IWL_MVM_RS_SR_NO_DECREASE)) { target_tpt = 100 * expected_current_tpt; IWL_DEBUG_RATE(mvm, "SR %d high. Find rate exceeding EXPECTED_CURRENT %d\n", @@ -1535,7 +1535,7 @@ static s32 rs_get_best_rate(struct iwl_mvm *mvm, } else { target_tpt = lq_sta->last_tpt; IWL_DEBUG_RATE(mvm, - "SR %d not thag good. Find rate exceeding ACTUAL_TPT %d\n", + "SR %d not that good. Find rate exceeding ACTUAL_TPT %d\n", success_ratio, target_tpt); } -- 2.20.1