From patchwork Fri Nov 15 01:48:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kan Yan X-Patchwork-Id: 11244703 X-Patchwork-Delegate: johannes@sipsolutions.net Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3D13213BD for ; Fri, 15 Nov 2019 01:49:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B9FA20725 for ; Fri, 15 Nov 2019 01:49:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cefrW9od" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727387AbfKOBtB (ORCPT ); Thu, 14 Nov 2019 20:49:01 -0500 Received: from mail-qv1-f73.google.com ([209.85.219.73]:48503 "EHLO mail-qv1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726956AbfKOBtB (ORCPT ); Thu, 14 Nov 2019 20:49:01 -0500 Received: by mail-qv1-f73.google.com with SMTP id w7so5526033qvs.15 for ; Thu, 14 Nov 2019 17:48:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc:content-transfer-encoding; bh=oN1s+xyXJHcU/9ntNolLXiksOYTgl1rPppuVcMJv4K0=; b=cefrW9odl+ZOqwctGc2jMjYS91NKgS4GNdkh3e1MVqBAGJfRhqCrcO0xbkH3Mw1/GL VsFwwUf/eZR94HTXQ6EHhRQSFr6s18bht/p0wPRyLJpvEDVhTOOBSvfJyMZHuLca0foT p8IHNPRmgF2LCDq/FVi3MIGUb4z/Nr82dkXe/yyjN7474R+YdErBexfoppHF31oSD1gW fuCcPRLBCFZTZk9cT6dYjmr2mG6NfY3kqQf0UvjK+erhnuFDXKnc9XJVzgctgE9vFLLR 1w1kNsFGhDeYz4zFMXXx5vZazGVBQ0Xp2iUHabDlgMnNGVsiSJ3J1OKbD/AwMCPGpwQi +a5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc:content-transfer-encoding; bh=oN1s+xyXJHcU/9ntNolLXiksOYTgl1rPppuVcMJv4K0=; b=VbMAQYrX+syCE6yR61TbRQN+6qJ8VUciv5mLcHvRmOPnhdNk7d060NY8g0irWpOvqO 5kuq1Zk/wwER38YOoFUs82n2RtPVPGZuIRLSsWQ8JVCoiPGQ8+TL1mvZj6rBPxOefnlc SkMbjkuDxG4PnpAGWh1sTVFTiqeFjr2ZCdp5qB2l3eF9EIs9NQnfnZbaYq9eE3vNROpZ FBJ7XndGI89cTJB59oUTSj9Il9xt/RkkZXZG/CfwHXzTRlZCIo92s6aTnMED3TMqbq72 iINiGWFO2gBtSaXdZP5/gEOrIaIqccaCw2lzWZCXuiKzvSdpWw0mmzj22/XLNJ+6T6aD ihNw== X-Gm-Message-State: APjAAAXw6eNVj8wsiWsvteO8gNyHRpSGCan/e/MLQC81fb5GiwpVGM5V RM7/+LnVWogUgJPRYKp4xtsGRHNl X-Google-Smtp-Source: APXvYqwxzvPtYkPZakqPJxvQnvlGwDHtVcpzL0cQIzT1jjoKHVcwWIrQbuiMoChOxP6kIm9xricRnvrI X-Received: by 2002:ad4:5246:: with SMTP id s6mr10954645qvq.59.1573782537386; Thu, 14 Nov 2019 17:48:57 -0800 (PST) Date: Thu, 14 Nov 2019 17:48:46 -0800 In-Reply-To: <20191115014846.126007-1-kyan@google.com> Message-Id: <20191115014846.126007-3-kyan@google.com> Mime-Version: 1.0 References: <20191115014846.126007-1-kyan@google.com> X-Mailer: git-send-email 2.24.0.432.g9d3f5f5b63-goog Subject: [v8 PATCH 2/2] mac80211: Implement Airtime-based Queue Limit (AQL) From: Kan Yan To: johannes@sipsolutions.net Cc: linux-wireless@vger.kernel.org, make-wifi-fast@lists.bufferbloat.net, toke@redhat.com, nbd@nbd.name, yiboz@codeaurora.org, john@phrozen.org, lorenzo@kernel.org, rmanohar@codeaurora.org, kevinhayes@google.com, Kan Yan Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org In order for the Fq_CoDel algorithm integrated in mac80211 layer to operate effectively to control excessive queueing latency, the CoDel algorithm requires an accurate measure of how long packets stays in the queue, AKA sojourn time. The sojourn time measured at the mac80211 layer doesn't include queueing latency in the lower layer (firmware/hardware) and CoDel expects lower layer to have a short queue. However, most 802.11ac chipsets offload tasks such TX aggregation to firmware or hardware, thus have a deep lower layer queue. Without a mechanism to control the lower layer queue size, packets only stay in mac80211 layer transiently before being sent to firmware queue. As a result, the sojourn time measured by CoDel in the mac80211 layer is almost always lower than the CoDel latency target, hence CoDel does little to control the latency, even when the lower layer queue causes excessive latency. The Byte Queue Limits (BQL) mechanism is commonly used to address the similar issue with wired network interface. However, this method cannot be applied directly to the wireless network interface. "Bytes" is not a suitable measure of queue depth in the wireless network, as the data rate can vary dramatically from station to station in the same network, from a few Mbps to over Gbps. This patch implements an Airtime-based Queue Limit (AQL) to make CoDel work effectively with wireless drivers that utilized firmware/hardware offloading. AQL allows each txq to release just enough packets to the lower layer to form 1-2 large aggregations to keep hardware fully utilized and retains the rest of the frames in mac80211 layer to be controlled by the CoDel algorithm. Signed-off-by: Kan Yan [ Toke: Keep API to set pending airtime internal, fix nits in commit msg ] Signed-off-by: Toke Høiland-Jørgensen --- include/net/cfg80211.h | 7 ++++ include/net/mac80211.h | 12 ++++++ net/mac80211/debugfs.c | 85 ++++++++++++++++++++++++++++++++++++++ net/mac80211/debugfs_sta.c | 43 ++++++++++++++----- net/mac80211/ieee80211_i.h | 4 ++ net/mac80211/main.c | 10 ++++- net/mac80211/sta_info.c | 38 +++++++++++++++++ net/mac80211/sta_info.h | 8 ++++ net/mac80211/tx.c | 47 +++++++++++++++++++-- 9 files changed, 240 insertions(+), 14 deletions(-) diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index 4ab2c49423dc..15f9f04de149 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -2602,6 +2602,13 @@ enum wiphy_params_flags { #define IEEE80211_DEFAULT_AIRTIME_WEIGHT 256 +/* The per TXQ device queue limit in airtime */ +#define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_L 4000 +#define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_H 8000 + +/* The per interface airtime threshold to switch to lower queue limit */ +#define IEEE80211_AQL_THRESHOLD 24000 + /** * struct cfg80211_pmksa - PMK Security Association * diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 4319596ef472..269be699e89c 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -5558,6 +5558,18 @@ void ieee80211_send_eosp_nullfunc(struct ieee80211_sta *pubsta, int tid); void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid, u32 tx_airtime, u32 rx_airtime); +/** + * ieee80211_txq_airtime_check - check if a txq can send frame to device + * + * @hw: pointer obtained from ieee80211_alloc_hw() + * @txq: pointer obtained from station or virtual interface + * + * Return true if the AQL's airtime limit has not been reached and the txq can + * continue to send more packets to the device. Otherwise return false. + */ +bool +ieee80211_txq_airtime_check(struct ieee80211_hw *hw, struct ieee80211_txq *txq); + /** * ieee80211_iter_keys - iterate keys programmed into the device * @hw: pointer obtained from ieee80211_alloc_hw() diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c index 568b3b276931..399d4e8b8546 100644 --- a/net/mac80211/debugfs.c +++ b/net/mac80211/debugfs.c @@ -148,6 +148,87 @@ static const struct file_operations aqm_ops = { .llseek = default_llseek, }; +static ssize_t aql_txq_limit_read(struct file *file, + char __user *user_buf, + size_t count, + loff_t *ppos) +{ + struct ieee80211_local *local = file->private_data; + char buf[400]; + int len = 0; + + len = scnprintf(buf, sizeof(buf), + "AC AQL limit low AQL limit high\n" + "VO %u %u\n" + "VI %u %u\n" + "BE %u %u\n" + "BK %u %u\n", + local->aql_txq_limit_low[IEEE80211_AC_VO], + local->aql_txq_limit_high[IEEE80211_AC_VO], + local->aql_txq_limit_low[IEEE80211_AC_VI], + local->aql_txq_limit_high[IEEE80211_AC_VI], + local->aql_txq_limit_low[IEEE80211_AC_BE], + local->aql_txq_limit_high[IEEE80211_AC_BE], + local->aql_txq_limit_low[IEEE80211_AC_BK], + local->aql_txq_limit_high[IEEE80211_AC_BK]); + return simple_read_from_buffer(user_buf, count, ppos, + buf, len); +} + +static ssize_t aql_txq_limit_write(struct file *file, + const char __user *user_buf, + size_t count, + loff_t *ppos) +{ + struct ieee80211_local *local = file->private_data; + char buf[100]; + size_t len; + u32 ac, q_limit_low, q_limit_high, q_limit_low_old, q_limit_high_old; + struct sta_info *sta; + + if (count > sizeof(buf)) + return -EINVAL; + + if (copy_from_user(buf, user_buf, count)) + return -EFAULT; + + buf[sizeof(buf) - 1] = 0; + len = strlen(buf); + if (len > 0 && buf[len - 1] == '\n') + buf[len - 1] = 0; + + if (sscanf(buf, "%u %u %u", &ac, &q_limit_low, &q_limit_high) != 3) + return -EINVAL; + + if (ac >= IEEE80211_NUM_ACS) + return -EINVAL; + + q_limit_low_old = local->aql_txq_limit_low[ac]; + q_limit_high_old = local->aql_txq_limit_high[ac]; + + local->aql_txq_limit_low[ac] = q_limit_low; + local->aql_txq_limit_high[ac] = q_limit_high; + + mutex_lock(&local->sta_mtx); + list_for_each_entry(sta, &local->sta_list, list) { + /* If a sta has customized queue limits, keep it */ + if (sta->airtime[ac].aql_limit_low == q_limit_low_old && + sta->airtime[ac].aql_limit_high == q_limit_high_old) { + sta->airtime[ac].aql_limit_low = q_limit_low; + sta->airtime[ac].aql_limit_high = q_limit_high; + } + } + mutex_unlock(&local->sta_mtx); + return count; +} + +static const struct file_operations aql_txq_limit_ops = { + .write = aql_txq_limit_write, + .read = aql_txq_limit_read, + .open = simple_open, + .llseek = default_llseek, +}; + static ssize_t force_tx_status_read(struct file *file, char __user *user_buf, size_t count, @@ -441,6 +522,10 @@ void debugfs_hw_add(struct ieee80211_local *local) debugfs_create_u16("airtime_flags", 0600, phyd, &local->airtime_flags); + DEBUGFS_ADD(aql_txq_limit); + debugfs_create_u32("aql_threshold", 0600, + phyd, &local->aql_threshold); + statsd = debugfs_create_dir("statistics", phyd); /* if the dir failed, don't put all the other things into the root! */ diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c index c8ad20c28c43..0185e6e5e5d1 100644 --- a/net/mac80211/debugfs_sta.c +++ b/net/mac80211/debugfs_sta.c @@ -197,10 +197,12 @@ static ssize_t sta_airtime_read(struct file *file, char __user *userbuf, { struct sta_info *sta = file->private_data; struct ieee80211_local *local = sta->sdata->local; - size_t bufsz = 200; + size_t bufsz = 400; char *buf = kzalloc(bufsz, GFP_KERNEL), *p = buf; u64 rx_airtime = 0, tx_airtime = 0; s64 deficit[IEEE80211_NUM_ACS]; + u32 q_depth[IEEE80211_NUM_ACS]; + u32 q_limit_l[IEEE80211_NUM_ACS], q_limit_h[IEEE80211_NUM_ACS]; ssize_t rv; int ac; @@ -212,19 +214,22 @@ static ssize_t sta_airtime_read(struct file *file, char __user *userbuf, rx_airtime += sta->airtime[ac].rx_airtime; tx_airtime += sta->airtime[ac].tx_airtime; deficit[ac] = sta->airtime[ac].deficit; + q_limit_l[ac] = sta->airtime[ac].aql_limit_low; + q_limit_h[ac] = sta->airtime[ac].aql_limit_high; spin_unlock_bh(&local->active_txq_lock[ac]); + q_depth[ac] = atomic_read(&sta->airtime[ac].aql_tx_pending); } p += scnprintf(p, bufsz + buf - p, "RX: %llu us\nTX: %llu us\nWeight: %u\n" - "Deficit: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n", - rx_airtime, - tx_airtime, - sta->airtime_weight, - deficit[0], - deficit[1], - deficit[2], - deficit[3]); + "Deficit: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n" + "Q depth: VO: %u us VI: %u us BE: %u us BK: %u us\n" + "Q limit[low/high]: VO: %u/%u VI: %u/%u BE: %u/%u BK: %u/%u\n", + rx_airtime, tx_airtime, sta->airtime_weight, + deficit[0], deficit[1], deficit[2], deficit[3], + q_depth[0], q_depth[1], q_depth[2], q_depth[3], + q_limit_l[0], q_limit_h[0], q_limit_l[1], q_limit_h[1], + q_limit_l[2], q_limit_h[2], q_limit_l[3], q_limit_h[3]), rv = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); kfree(buf); @@ -236,7 +241,25 @@ static ssize_t sta_airtime_write(struct file *file, const char __user *userbuf, { struct sta_info *sta = file->private_data; struct ieee80211_local *local = sta->sdata->local; - int ac; + u32 ac, q_limit_l, q_limit_h; + char _buf[100] = {}, *buf = _buf; + + if (count > sizeof(_buf)) + return -EINVAL; + + if (copy_from_user(buf, userbuf, count)) + return -EFAULT; + + buf[sizeof(_buf) - 1] = '\0'; + if (sscanf(buf, "queue limit %u %u %u", &ac, &q_limit_l, &q_limit_h) + != 3) + return -EINVAL; + + if (ac >= IEEE80211_NUM_ACS) + return -EINVAL; + + sta->airtime[ac].aql_limit_low = q_limit_l; + sta->airtime[ac].aql_limit_high = q_limit_h; for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { spin_lock_bh(&local->active_txq_lock[ac]); diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 225ea4e3cd76..ad15b3be8bb3 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1142,6 +1142,10 @@ struct ieee80211_local { u16 schedule_round[IEEE80211_NUM_ACS]; u16 airtime_flags; + u32 aql_txq_limit_low[IEEE80211_NUM_ACS]; + u32 aql_txq_limit_high[IEEE80211_NUM_ACS]; + u32 aql_threshold; + atomic_t aql_total_pending_airtime; const struct ieee80211_ops *ops; diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 2d05c4cfaf6d..6cca0853f183 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -667,8 +667,16 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len, for (i = 0; i < IEEE80211_NUM_ACS; i++) { INIT_LIST_HEAD(&local->active_txqs[i]); spin_lock_init(&local->active_txq_lock[i]); + local->aql_txq_limit_low[i] = IEEE80211_DEFAULT_AQL_TXQ_LIMIT_L; + local->aql_txq_limit_high[i] = + IEEE80211_DEFAULT_AQL_TXQ_LIMIT_H; } - local->airtime_flags = AIRTIME_USE_TX | AIRTIME_USE_RX; + + local->airtime_flags = AIRTIME_USE_TX | + AIRTIME_USE_RX | + AIRTIME_USE_AQL; + local->aql_threshold = IEEE80211_AQL_THRESHOLD; + atomic_set(&local->aql_total_pending_airtime, 0); INIT_LIST_HEAD(&local->chanctx_list); mutex_init(&local->chanctx_mtx); diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 8d3a2389b055..6df995d9f4b1 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -396,6 +396,9 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata, skb_queue_head_init(&sta->ps_tx_buf[i]); skb_queue_head_init(&sta->tx_filtered[i]); sta->airtime[i].deficit = sta->airtime_weight; + atomic_set(&sta->airtime[i].aql_tx_pending, 0); + sta->airtime[i].aql_limit_low = local->aql_txq_limit_low[i]; + sta->airtime[i].aql_limit_high = local->aql_txq_limit_high[i]; } for (i = 0; i < IEEE80211_NUM_TIDS; i++) @@ -1893,6 +1896,41 @@ void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid, } EXPORT_SYMBOL(ieee80211_sta_register_airtime); +void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local, + struct sta_info *sta, u8 ac, + u16 tx_airtime, bool tx_completed) +{ + int tx_pending; + + if (!tx_completed) { + if (sta) + atomic_add(tx_airtime, + &sta->airtime[ac].aql_tx_pending); + + atomic_add(tx_airtime, &local->aql_total_pending_airtime); + return; + } + + if (sta) { + atomic_sub(tx_airtime, &sta->airtime[ac].aql_tx_pending); + tx_pending = atomic_read(&sta->airtime[ac].aql_tx_pending); + if (WARN_ONCE(tx_pending < 0, + "STA %pM AC %d txq pending airtime underflow: %u, %u", + sta->addr, ac, tx_pending, tx_airtime)) + atomic_cmpxchg(&sta->airtime[ac].aql_tx_pending, + tx_pending, 0); + } + + atomic_sub(tx_airtime, &local->aql_total_pending_airtime); + tx_pending = atomic_read(&local->aql_total_pending_airtime); + if (WARN_ONCE(tx_pending < 0, + "Device %s AC %d pending airtime underflow: %u, %u", + wiphy_name(local->hw.wiphy), ac, tx_pending, + tx_airtime)) + atomic_cmpxchg(&local->aql_total_pending_airtime, + tx_pending, 0); +} + int sta_info_move_state(struct sta_info *sta, enum ieee80211_sta_state new_state) { diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 369c2dddce52..c8823bd0e55f 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -127,13 +127,21 @@ enum ieee80211_agg_stop_reason { /* Debugfs flags to enable/disable use of RX/TX airtime in scheduler */ #define AIRTIME_USE_TX BIT(0) #define AIRTIME_USE_RX BIT(1) +#define AIRTIME_USE_AQL BIT(2) struct airtime_info { u64 rx_airtime; u64 tx_airtime; s64 deficit; + atomic_t aql_tx_pending; /* Estimated airtime for frames pending */ + u32 aql_limit_low; + u32 aql_limit_high; }; +void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local, + struct sta_info *sta, u8 ac, + u16 tx_airtime, bool tx_completed); + struct sta_info; /** diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 238c47be5fe4..f53d56ef535a 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3672,7 +3672,8 @@ struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac) { struct ieee80211_local *local = hw_to_local(hw); struct ieee80211_txq *ret = NULL; - struct txq_info *txqi = NULL; + struct txq_info *txqi = NULL, *head = NULL; + bool found_eligible_txq = false; spin_lock_bh(&local->active_txq_lock[ac]); @@ -3683,13 +3684,26 @@ struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac) if (!txqi) goto out; + if (txqi == head && !found_eligible_txq) + goto out; + + if (!head) + head = txqi; + if (txqi->txq.sta) { struct sta_info *sta = container_of(txqi->txq.sta, - struct sta_info, sta); + struct sta_info, sta); + bool aql_check = ieee80211_txq_airtime_check(hw, &txqi->txq); + s64 deficit = sta->airtime[txqi->txq.ac].deficit; + + if (aql_check) + found_eligible_txq = true; - if (sta->airtime[txqi->txq.ac].deficit < 0) { + if (deficit < 0) sta->airtime[txqi->txq.ac].deficit += sta->airtime_weight; + + if (deficit < 0 || !aql_check) { list_move_tail(&txqi->schedule_order, &local->active_txqs[txqi->txq.ac]); goto begin; @@ -3743,6 +3757,33 @@ void __ieee80211_schedule_txq(struct ieee80211_hw *hw, } EXPORT_SYMBOL(__ieee80211_schedule_txq); +bool ieee80211_txq_airtime_check(struct ieee80211_hw *hw, + struct ieee80211_txq *txq) +{ + struct sta_info *sta; + struct ieee80211_local *local = hw_to_local(hw); + + if (!(local->airtime_flags & AIRTIME_USE_AQL)) + return true; + + if (!txq->sta) + return true; + + sta = container_of(txq->sta, struct sta_info, sta); + if (atomic_read(&sta->airtime[txq->ac].aql_tx_pending) < + sta->airtime[txq->ac].aql_limit_low) + return true; + + if (atomic_read(&local->aql_total_pending_airtime) < + local->aql_threshold && + atomic_read(&sta->airtime[txq->ac].aql_tx_pending) < + sta->airtime[txq->ac].aql_limit_high) + return true; + + return false; +} +EXPORT_SYMBOL(ieee80211_txq_airtime_check); + bool ieee80211_txq_may_transmit(struct ieee80211_hw *hw, struct ieee80211_txq *txq) {