From patchwork Mon Oct 5 14:36:52 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Coelho X-Patchwork-Id: 7328371 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: X-Original-To: patchwork-linux-wireless@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 1CF159F2F7 for ; Mon, 5 Oct 2015 15:01:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3478F2069E for ; Mon, 5 Oct 2015 15:01:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A26A206A5 for ; Mon, 5 Oct 2015 15:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752507AbbJEPBk (ORCPT ); Mon, 5 Oct 2015 11:01:40 -0400 Received: from paleale.coelho.fi ([176.9.41.70]:57186 "EHLO farmhouse.coelho.fi" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752472AbbJEPBj (ORCPT ); Mon, 5 Oct 2015 11:01:39 -0400 Received: from 91-157-79-26.elisa-laajakaista.fi ([91.157.79.26] helo=dubbel.ger.corp.intel.com) by farmhouse.coelho.fi with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_CBC_SHA256:128) (Exim 4.86) (envelope-from ) id 1Zj6tR-0003L2-9d; Mon, 05 Oct 2015 17:37:34 +0300 From: Luca Coelho To: linux-wireless@vger.kernel.org Cc: Eyal Shapira , Eyal Shapira , Luca Coelho Date: Mon, 5 Oct 2015 17:36:52 +0300 Message-Id: <1444055820-27506-21-git-send-email-luca@coelho.fi> X-Mailer: git-send-email 2.5.3 In-Reply-To: <1444050759.27220.15.camel@coelho.fi> References: <1444050759.27220.15.camel@coelho.fi> X-SA-Exim-Connect-IP: 91.157.79.26 X-SA-Exim-Mail-From: luca@coelho.fi X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Subject: [PATCH 21/29] iwlwifi: mvm: rs: fix success ratio comparison in rs_get_best_rate X-SA-Exim-Version: 4.2.1 (built Mon, 06 Jul 2015 07:28:29 +0000) X-SA-Exim-Scanned: Yes (on farmhouse.coelho.fi) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Eyal Shapira 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 2bf2a08..435e1e4 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); }