This patch series port the Airtime Queue Limits concept from the out-of-tree
ath10k implementation[0] to mac80211. This version takes my patch to do the
throttling in mac80211, and replaces the driver API with the mechanism from
Toke's series, which instead calculated the expected airtime at dequeue time
inside mac80211, storing it in the SKB cb field.
This version has been tested on QCA9984 platform.
[0] https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1703105/7
Changelog:
v8:
- Includes Toke's v7 version of "mac80211: Import airtime calculation code from mt76"
- Don't clobber sta's customized queue limit when configuring the default via debugfs
- Fix a racing condition when reset aql_tx_pending.
v7:
- Fix aql_total_pending_airtime underflow due to insufficient locking.
v6:
- Fix sta lookup in ieee80211_report_used_skb().
- Move call to ieee80211_sta_update_pending_airtime() to a bit later in
__ieee80211_tx_status()
v5:
- Add missing export of ieee80211_calc_rx_airtime() and make
ieee80211_calc_tx_airtime_rate() static (kbuildbot).
- Use skb_get_queue_mapping() to get the AC from the skb.
- Take basic rate configuration for the BSS into account when calculating
multicast rate.
v4:
- Fix calculation that clamps the maximum airtime to fit into 10 bits
- Incorporate Rich Brown's nits for the commit message in Kan's patch
- Add fewer local variables to ieee80211_tx_dequeue()
v3:
- Move the tx_time_est field so it's shared with ack_frame_id, and use units
of 4us for the value stored in it.
- Move the addition of the Ethernet header size into ieee80211_calc_expected_tx_airtime()
v2:
- Integrate Kan's approach to airtime throttling.
- Hopefully fix the cb struct alignment on big-endian architectures.
Kan Yan (1):
mac80211: Implement Airtime-based Queue Limit (AQL)
Toke Høiland-Jørgensen (1):
mac80211: Import airtime calculation code from mt76
include/net/cfg80211.h | 7 +
include/net/mac80211.h | 41 +++
net/mac80211/Makefile | 3 +-
net/mac80211/airtime.c | 597 +++++++++++++++++++++++++++++++++++++
net/mac80211/debugfs.c | 85 ++++++
net/mac80211/debugfs_sta.c | 43 ++-
net/mac80211/ieee80211_i.h | 8 +
net/mac80211/main.c | 10 +-
net/mac80211/sta_info.c | 38 +++
net/mac80211/sta_info.h | 8 +
net/mac80211/tx.c | 47 ++-
11 files changed, 872 insertions(+), 15 deletions(-)
create mode 100644 net/mac80211/airtime.c
--
2.24.0.rc1.363.gb1bccd3e3d-goog
From: Toke Høiland-Jørgensen <[email protected]>
Felix recently added code to calculate airtime of packets to the mt76
driver. Import this into mac80211 so we can use it for airtime queue limit
calculations.
The airtime.c file is copied verbatim from the mt76 driver, and adjusted to
be usable in mac80211. This involves:
- Switching to mac80211 data structures.
- Adding support for 160 MHz channels and HE mode.
- Moving the symbol and duration calculations around a bit to avoid
rounding with the higher rates and longer symbol times used for HE rates.
The per-rate TX rate calculation is also split out to its own function so
it can be used directly for the AQL calculations later.
Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
---
include/net/mac80211.h | 29 ++
net/mac80211/Makefile | 3 +-
net/mac80211/airtime.c | 597 +++++++++++++++++++++++++++++++++++++
net/mac80211/ieee80211_i.h | 4 +
4 files changed, 632 insertions(+), 1 deletion(-)
create mode 100644 net/mac80211/airtime.c
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 02a8a4986f21..4319596ef472 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -6417,4 +6417,33 @@ void ieee80211_nan_func_match(struct ieee80211_vif *vif,
struct cfg80211_nan_match_params *match,
gfp_t gfp);
+/**
+ * ieee80211_calc_rx_airtime - calculate estimated transmission airtime for RX.
+ *
+ * This function calculates the estimated airtime usage of a frame based on the
+ * rate information in the RX status struct and the frame length.
+ *
+ * @hw: pointer as obtained from ieee80211_alloc_hw()
+ * @status: &struct ieee80211_rx_status containing the transmission rate
+ * information.
+ * @len: frame length in bytes
+ */
+u32 ieee80211_calc_rx_airtime(struct ieee80211_hw *hw,
+ struct ieee80211_rx_status *status,
+ int len);
+
+/**
+ * ieee80211_calc_tx_airtime - calculate estimated transmission airtime for TX.
+ *
+ * This function calculates the estimated airtime usage of a frame based on the
+ * rate information in the TX info struct and the frame length.
+ *
+ * @hw: pointer as obtained from ieee80211_alloc_hw()
+ * @info: &struct ieee80211_tx_info of the frame.
+ * @len: frame length in bytes
+ */
+u32 ieee80211_calc_tx_airtime(struct ieee80211_hw *hw,
+ struct ieee80211_tx_info *info,
+ int len);
+
#endif /* MAC80211_H */
diff --git a/net/mac80211/Makefile b/net/mac80211/Makefile
index 4f03ebe732fa..6cbb1286d6c0 100644
--- a/net/mac80211/Makefile
+++ b/net/mac80211/Makefile
@@ -32,7 +32,8 @@ mac80211-y := \
chan.o \
trace.o mlme.o \
tdls.o \
- ocb.o
+ ocb.o \
+ airtime.o
mac80211-$(CONFIG_MAC80211_LEDS) += led.o
mac80211-$(CONFIG_MAC80211_DEBUGFS) += \
diff --git a/net/mac80211/airtime.c b/net/mac80211/airtime.c
new file mode 100644
index 000000000000..0c2a0bb94727
--- /dev/null
+++ b/net/mac80211/airtime.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: ISC
+/*
+ * Copyright (C) 2019 Felix Fietkau <[email protected]>
+ */
+
+#include <net/mac80211.h>
+#include "ieee80211_i.h"
+#include "sta_info.h"
+
+#define AVG_PKT_SIZE 1024
+
+/* Number of bits for an average sized packet */
+#define MCS_NBITS (AVG_PKT_SIZE << 3)
+
+/* Number of kilo-symbols (symbols * 1024) for a packet with (bps) bits per
+ * symbol. We use k-symbols to avoid rounding in the _TIME macros below.
+ */
+#define MCS_N_KSYMS(bps) DIV_ROUND_UP(MCS_NBITS << 10, (bps))
+
+/* Transmission time (in 1024 * usec) for a packet containing (ksyms) * 1024
+ * symbols.
+ */
+#define MCS_SYMBOL_TIME(sgi, ksyms) \
+ (sgi ? \
+ ((ksyms) * 4 * 18) / 20 : /* 3.6 us per sym */ \
+ ((ksyms) * 4) /* 4.0 us per sym */ \
+ )
+
+/* Transmit duration for the raw data part of an average sized packet */
+#define MCS_DURATION(streams, sgi, bps) \
+ ((u32)MCS_SYMBOL_TIME(sgi, MCS_N_KSYMS((streams) * (bps))))
+
+#define MCS_DURATION_S(shift, streams, sgi, bps) \
+ ((u16)((MCS_DURATION(streams, sgi, bps) >> shift)))
+
+/* These should match the values in enum nl80211_he_gi */
+#define HE_GI_08 0
+#define HE_GI_16 1
+#define HE_GI_32 2
+
+/* Transmission time (1024 usec) for a packet containing (ksyms) * k-symbols */
+#define HE_SYMBOL_TIME(gi, ksyms) \
+ (gi == HE_GI_08 ? \
+ ((ksyms) * 16 * 17) / 20 : /* 13.6 us per sym */ \
+ (gi == HE_GI_16 ? \
+ ((ksyms) * 16 * 18) / 20 : /* 14.4 us per sym */ \
+ ((ksyms) * 16) /* 16.0 us per sym */ \
+ ))
+
+/* Transmit duration for the raw data part of an average sized packet */
+#define HE_DURATION(streams, gi, bps) \
+ ((u32)HE_SYMBOL_TIME(gi, MCS_N_KSYMS((streams) * (bps))))
+
+#define HE_DURATION_S(shift, streams, gi, bps) \
+ (HE_DURATION(streams, gi, bps) >> shift)
+
+#define BW_20 0
+#define BW_40 1
+#define BW_80 2
+#define BW_160 3
+
+/*
+ * Define group sort order: HT40 -> SGI -> #streams
+ */
+#define IEEE80211_MAX_STREAMS 4
+#define IEEE80211_HT_STREAM_GROUPS 4 /* BW(=2) * SGI(=2) */
+#define IEEE80211_VHT_STREAM_GROUPS 8 /* BW(=4) * SGI(=2) */
+
+#define IEEE80211_HE_MAX_STREAMS 8
+#define IEEE80211_HE_STREAM_GROUPS 12 /* BW(=4) * GI(=3) */
+
+#define IEEE80211_HT_GROUPS_NB (IEEE80211_MAX_STREAMS * \
+ IEEE80211_HT_STREAM_GROUPS)
+#define IEEE80211_VHT_GROUPS_NB (IEEE80211_MAX_STREAMS * \
+ IEEE80211_VHT_STREAM_GROUPS)
+#define IEEE80211_HE_GROUPS_NB (IEEE80211_HE_MAX_STREAMS * \
+ IEEE80211_HE_STREAM_GROUPS)
+#define IEEE80211_GROUPS_NB (IEEE80211_HT_GROUPS_NB + \
+ IEEE80211_VHT_GROUPS_NB + \
+ IEEE80211_HE_GROUPS_NB)
+
+#define IEEE80211_HT_GROUP_0 0
+#define IEEE80211_VHT_GROUP_0 (IEEE80211_HT_GROUP_0 + IEEE80211_HT_GROUPS_NB)
+#define IEEE80211_HE_GROUP_0 (IEEE80211_VHT_GROUP_0 + IEEE80211_VHT_GROUPS_NB)
+
+#define MCS_GROUP_RATES 12
+
+#define HT_GROUP_IDX(_streams, _sgi, _ht40) \
+ IEEE80211_HT_GROUP_0 + \
+ IEEE80211_MAX_STREAMS * 2 * _ht40 + \
+ IEEE80211_MAX_STREAMS * _sgi + \
+ _streams - 1
+
+#define _MAX(a, b) (((a)>(b))?(a):(b))
+
+#define GROUP_SHIFT(duration) \
+ _MAX(0, 16 - __builtin_clz(duration))
+
+/* MCS rate information for an MCS group */
+#define __MCS_GROUP(_streams, _sgi, _ht40, _s) \
+ [HT_GROUP_IDX(_streams, _sgi, _ht40)] = { \
+ .shift = _s, \
+ .duration = { \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 54 : 26), \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 108 : 52), \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 162 : 78), \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 216 : 104), \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 324 : 156), \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 432 : 208), \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 486 : 234), \
+ MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 540 : 260) \
+ } \
+}
+
+#define MCS_GROUP_SHIFT(_streams, _sgi, _ht40) \
+ GROUP_SHIFT(MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26))
+
+#define MCS_GROUP(_streams, _sgi, _ht40) \
+ __MCS_GROUP(_streams, _sgi, _ht40, \
+ MCS_GROUP_SHIFT(_streams, _sgi, _ht40))
+
+#define VHT_GROUP_IDX(_streams, _sgi, _bw) \
+ (IEEE80211_VHT_GROUP_0 + \
+ IEEE80211_MAX_STREAMS * 2 * (_bw) + \
+ IEEE80211_MAX_STREAMS * (_sgi) + \
+ (_streams) - 1)
+
+#define BW2VBPS(_bw, r4, r3, r2, r1) \
+ (_bw == BW_160 ? r4 : _bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
+
+#define __VHT_GROUP(_streams, _sgi, _bw, _s) \
+ [VHT_GROUP_IDX(_streams, _sgi, _bw)] = { \
+ .shift = _s, \
+ .duration = { \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 234, 117, 54, 26)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 468, 234, 108, 52)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 702, 351, 162, 78)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 936, 468, 216, 104)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 1404, 702, 324, 156)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 1872, 936, 432, 208)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 2106, 1053, 486, 234)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 2340, 1170, 540, 260)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 2808, 1404, 648, 312)), \
+ MCS_DURATION_S(_s, _streams, _sgi, \
+ BW2VBPS(_bw, 3120, 1560, 720, 346)) \
+ } \
+}
+
+#define VHT_GROUP_SHIFT(_streams, _sgi, _bw) \
+ GROUP_SHIFT(MCS_DURATION(_streams, _sgi, \
+ BW2VBPS(_bw, 243, 117, 54, 26)))
+
+#define VHT_GROUP(_streams, _sgi, _bw) \
+ __VHT_GROUP(_streams, _sgi, _bw, \
+ VHT_GROUP_SHIFT(_streams, _sgi, _bw))
+
+
+#define HE_GROUP_IDX(_streams, _gi, _bw) \
+ (IEEE80211_HE_GROUP_0 + \
+ IEEE80211_HE_MAX_STREAMS * 2 * (_bw) + \
+ IEEE80211_HE_MAX_STREAMS * (_gi) + \
+ (_streams) - 1)
+
+#define __HE_GROUP(_streams, _gi, _bw, _s) \
+ [HE_GROUP_IDX(_streams, _gi, _bw)] = { \
+ .shift = _s, \
+ .duration = { \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 979, 489, 230, 115)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 1958, 979, 475, 230)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 2937, 1468, 705, 345)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 3916, 1958, 936, 475)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 5875, 2937, 1411, 705)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 7833, 3916, 1872, 936)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 8827, 4406, 2102, 1051)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 9806, 4896, 2347, 1166)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 11764, 5875, 2808, 1411)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 13060, 6523, 3124, 1555)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 14702, 7344, 3513, 1756)), \
+ HE_DURATION_S(_s, _streams, _gi, \
+ BW2VBPS(_bw, 16329, 8164, 3902, 1944)) \
+ } \
+}
+
+#define HE_GROUP_SHIFT(_streams, _gi, _bw) \
+ GROUP_SHIFT(HE_DURATION(_streams, _gi, \
+ BW2VBPS(_bw, 979, 489, 230, 115)))
+
+#define HE_GROUP(_streams, _gi, _bw) \
+ __HE_GROUP(_streams, _gi, _bw, \
+ HE_GROUP_SHIFT(_streams, _gi, _bw))
+struct mcs_group {
+ u8 shift;
+ u16 duration[MCS_GROUP_RATES];
+};
+
+static const struct mcs_group airtime_mcs_groups[] = {
+ MCS_GROUP(1, 0, BW_20),
+ MCS_GROUP(2, 0, BW_20),
+ MCS_GROUP(3, 0, BW_20),
+ MCS_GROUP(4, 0, BW_20),
+
+ MCS_GROUP(1, 1, BW_20),
+ MCS_GROUP(2, 1, BW_20),
+ MCS_GROUP(3, 1, BW_20),
+ MCS_GROUP(4, 1, BW_20),
+
+ MCS_GROUP(1, 0, BW_40),
+ MCS_GROUP(2, 0, BW_40),
+ MCS_GROUP(3, 0, BW_40),
+ MCS_GROUP(4, 0, BW_40),
+
+ MCS_GROUP(1, 1, BW_40),
+ MCS_GROUP(2, 1, BW_40),
+ MCS_GROUP(3, 1, BW_40),
+ MCS_GROUP(4, 1, BW_40),
+
+ VHT_GROUP(1, 0, BW_20),
+ VHT_GROUP(2, 0, BW_20),
+ VHT_GROUP(3, 0, BW_20),
+ VHT_GROUP(4, 0, BW_20),
+
+ VHT_GROUP(1, 1, BW_20),
+ VHT_GROUP(2, 1, BW_20),
+ VHT_GROUP(3, 1, BW_20),
+ VHT_GROUP(4, 1, BW_20),
+
+ VHT_GROUP(1, 0, BW_40),
+ VHT_GROUP(2, 0, BW_40),
+ VHT_GROUP(3, 0, BW_40),
+ VHT_GROUP(4, 0, BW_40),
+
+ VHT_GROUP(1, 1, BW_40),
+ VHT_GROUP(2, 1, BW_40),
+ VHT_GROUP(3, 1, BW_40),
+ VHT_GROUP(4, 1, BW_40),
+
+ VHT_GROUP(1, 0, BW_80),
+ VHT_GROUP(2, 0, BW_80),
+ VHT_GROUP(3, 0, BW_80),
+ VHT_GROUP(4, 0, BW_80),
+
+ VHT_GROUP(1, 1, BW_80),
+ VHT_GROUP(2, 1, BW_80),
+ VHT_GROUP(3, 1, BW_80),
+ VHT_GROUP(4, 1, BW_80),
+
+ VHT_GROUP(1, 0, BW_160),
+ VHT_GROUP(2, 0, BW_160),
+ VHT_GROUP(3, 0, BW_160),
+ VHT_GROUP(4, 0, BW_160),
+
+ VHT_GROUP(1, 1, BW_160),
+ VHT_GROUP(2, 1, BW_160),
+ VHT_GROUP(3, 1, BW_160),
+ VHT_GROUP(4, 1, BW_160),
+
+ HE_GROUP(1, HE_GI_08, BW_20),
+ HE_GROUP(2, HE_GI_08, BW_20),
+ HE_GROUP(3, HE_GI_08, BW_20),
+ HE_GROUP(4, HE_GI_08, BW_20),
+ HE_GROUP(5, HE_GI_08, BW_20),
+ HE_GROUP(6, HE_GI_08, BW_20),
+ HE_GROUP(7, HE_GI_08, BW_20),
+ HE_GROUP(8, HE_GI_08, BW_20),
+
+ HE_GROUP(1, HE_GI_16, BW_20),
+ HE_GROUP(2, HE_GI_16, BW_20),
+ HE_GROUP(3, HE_GI_16, BW_20),
+ HE_GROUP(4, HE_GI_16, BW_20),
+ HE_GROUP(5, HE_GI_16, BW_20),
+ HE_GROUP(6, HE_GI_16, BW_20),
+ HE_GROUP(7, HE_GI_16, BW_20),
+ HE_GROUP(8, HE_GI_16, BW_20),
+
+ HE_GROUP(1, HE_GI_32, BW_20),
+ HE_GROUP(2, HE_GI_32, BW_20),
+ HE_GROUP(3, HE_GI_32, BW_20),
+ HE_GROUP(4, HE_GI_32, BW_20),
+ HE_GROUP(5, HE_GI_32, BW_20),
+ HE_GROUP(6, HE_GI_32, BW_20),
+ HE_GROUP(7, HE_GI_32, BW_20),
+ HE_GROUP(8, HE_GI_32, BW_20),
+
+ HE_GROUP(1, HE_GI_08, BW_40),
+ HE_GROUP(2, HE_GI_08, BW_40),
+ HE_GROUP(3, HE_GI_08, BW_40),
+ HE_GROUP(4, HE_GI_08, BW_40),
+ HE_GROUP(5, HE_GI_08, BW_40),
+ HE_GROUP(6, HE_GI_08, BW_40),
+ HE_GROUP(7, HE_GI_08, BW_40),
+ HE_GROUP(8, HE_GI_08, BW_40),
+
+ HE_GROUP(1, HE_GI_16, BW_40),
+ HE_GROUP(2, HE_GI_16, BW_40),
+ HE_GROUP(3, HE_GI_16, BW_40),
+ HE_GROUP(4, HE_GI_16, BW_40),
+ HE_GROUP(5, HE_GI_16, BW_40),
+ HE_GROUP(6, HE_GI_16, BW_40),
+ HE_GROUP(7, HE_GI_16, BW_40),
+ HE_GROUP(8, HE_GI_16, BW_40),
+
+ HE_GROUP(1, HE_GI_32, BW_40),
+ HE_GROUP(2, HE_GI_32, BW_40),
+ HE_GROUP(3, HE_GI_32, BW_40),
+ HE_GROUP(4, HE_GI_32, BW_40),
+ HE_GROUP(5, HE_GI_32, BW_40),
+ HE_GROUP(6, HE_GI_32, BW_40),
+ HE_GROUP(7, HE_GI_32, BW_40),
+ HE_GROUP(8, HE_GI_32, BW_40),
+
+ HE_GROUP(1, HE_GI_08, BW_80),
+ HE_GROUP(2, HE_GI_08, BW_80),
+ HE_GROUP(3, HE_GI_08, BW_80),
+ HE_GROUP(4, HE_GI_08, BW_80),
+ HE_GROUP(5, HE_GI_08, BW_80),
+ HE_GROUP(6, HE_GI_08, BW_80),
+ HE_GROUP(7, HE_GI_08, BW_80),
+ HE_GROUP(8, HE_GI_08, BW_80),
+
+ HE_GROUP(1, HE_GI_16, BW_80),
+ HE_GROUP(2, HE_GI_16, BW_80),
+ HE_GROUP(3, HE_GI_16, BW_80),
+ HE_GROUP(4, HE_GI_16, BW_80),
+ HE_GROUP(5, HE_GI_16, BW_80),
+ HE_GROUP(6, HE_GI_16, BW_80),
+ HE_GROUP(7, HE_GI_16, BW_80),
+ HE_GROUP(8, HE_GI_16, BW_80),
+
+ HE_GROUP(1, HE_GI_32, BW_80),
+ HE_GROUP(2, HE_GI_32, BW_80),
+ HE_GROUP(3, HE_GI_32, BW_80),
+ HE_GROUP(4, HE_GI_32, BW_80),
+ HE_GROUP(5, HE_GI_32, BW_80),
+ HE_GROUP(6, HE_GI_32, BW_80),
+ HE_GROUP(7, HE_GI_32, BW_80),
+ HE_GROUP(8, HE_GI_32, BW_80),
+
+ HE_GROUP(1, HE_GI_08, BW_160),
+ HE_GROUP(2, HE_GI_08, BW_160),
+ HE_GROUP(3, HE_GI_08, BW_160),
+ HE_GROUP(4, HE_GI_08, BW_160),
+ HE_GROUP(5, HE_GI_08, BW_160),
+ HE_GROUP(6, HE_GI_08, BW_160),
+ HE_GROUP(7, HE_GI_08, BW_160),
+ HE_GROUP(8, HE_GI_08, BW_160),
+
+ HE_GROUP(1, HE_GI_16, BW_160),
+ HE_GROUP(2, HE_GI_16, BW_160),
+ HE_GROUP(3, HE_GI_16, BW_160),
+ HE_GROUP(4, HE_GI_16, BW_160),
+ HE_GROUP(5, HE_GI_16, BW_160),
+ HE_GROUP(6, HE_GI_16, BW_160),
+ HE_GROUP(7, HE_GI_16, BW_160),
+ HE_GROUP(8, HE_GI_16, BW_160),
+
+ HE_GROUP(1, HE_GI_32, BW_160),
+ HE_GROUP(2, HE_GI_32, BW_160),
+ HE_GROUP(3, HE_GI_32, BW_160),
+ HE_GROUP(4, HE_GI_32, BW_160),
+ HE_GROUP(5, HE_GI_32, BW_160),
+ HE_GROUP(6, HE_GI_32, BW_160),
+ HE_GROUP(7, HE_GI_32, BW_160),
+ HE_GROUP(8, HE_GI_32, BW_160),
+};
+
+static u32
+ieee80211_calc_legacy_rate_duration(u16 bitrate, bool short_pre,
+ bool cck, int len)
+{
+ u32 duration;
+
+ if (cck) {
+ duration = 144 + 48; /* preamble + PLCP */
+ if (short_pre)
+ duration >>= 1;
+
+ duration += 10; /* SIFS */
+ } else {
+ duration = 20 + 16; /* premable + SIFS */
+ }
+
+ len <<= 3;
+ duration += (len * 10) / bitrate;
+
+ return duration;
+}
+
+u32 ieee80211_calc_rx_airtime(struct ieee80211_hw *hw,
+ struct ieee80211_rx_status *status,
+ int len)
+{
+ struct ieee80211_supported_band *sband;
+ const struct ieee80211_rate *rate;
+ bool sgi = status->enc_flags & RX_ENC_FLAG_SHORT_GI;
+ bool sp = status->enc_flags & RX_ENC_FLAG_SHORTPRE;
+ int bw, streams;
+ int group, idx;
+ u32 duration;
+ bool cck;
+
+ switch (status->bw) {
+ case RATE_INFO_BW_20:
+ bw = BW_20;
+ break;
+ case RATE_INFO_BW_40:
+ bw = BW_40;
+ break;
+ case RATE_INFO_BW_80:
+ bw = BW_80;
+ break;
+ case RATE_INFO_BW_160:
+ bw = BW_160;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+
+ switch (status->encoding) {
+ case RX_ENC_LEGACY:
+ if (WARN_ON_ONCE(status->band > NL80211_BAND_5GHZ))
+ return 0;
+
+ sband = hw->wiphy->bands[status->band];
+ if (!sband || status->rate_idx > sband->n_bitrates)
+ return 0;
+
+ rate = &sband->bitrates[status->rate_idx];
+ cck = rate->flags & IEEE80211_RATE_MANDATORY_B;
+
+ return ieee80211_calc_legacy_rate_duration(rate->bitrate, sp,
+ cck, len);
+
+ case RX_ENC_VHT:
+ streams = status->nss;
+ idx = status->rate_idx;
+ group = VHT_GROUP_IDX(streams, sgi, bw);
+ break;
+ case RX_ENC_HT:
+ streams = ((status->rate_idx >> 3) & 3) + 1;
+ idx = status->rate_idx & 7;
+ group = HT_GROUP_IDX(streams, sgi, bw);
+ break;
+ case RX_ENC_HE:
+ streams = status->nss;
+ idx = status->rate_idx;
+ group = HE_GROUP_IDX(streams, status->he_gi, bw);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+
+ if (WARN_ON_ONCE((status->encoding != RX_ENC_HE && streams > 4) ||
+ (status->encoding == RX_ENC_HE && streams > 8)))
+ return 0;
+
+ duration = airtime_mcs_groups[group].duration[idx];
+ duration <<= airtime_mcs_groups[group].shift;
+ duration *= len;
+ duration /= AVG_PKT_SIZE;
+ duration /= 1024;
+
+ duration += 36 + (streams << 2);
+
+ return duration;
+}
+EXPORT_SYMBOL_GPL(ieee80211_calc_rx_airtime);
+
+static u32 ieee80211_calc_tx_airtime_rate(struct ieee80211_hw *hw,
+ struct ieee80211_tx_rate *rate,
+ u8 band, int len)
+{
+ struct ieee80211_rx_status stat = {
+ .band = band,
+ };
+
+ if (rate->idx < 0 || !rate->count)
+ return 0;
+
+ if (rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
+ stat.bw = RATE_INFO_BW_80;
+ else if (rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+ stat.bw = RATE_INFO_BW_40;
+ else
+ stat.bw = RATE_INFO_BW_20;
+
+ stat.enc_flags = 0;
+ if (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)
+ stat.enc_flags |= RX_ENC_FLAG_SHORTPRE;
+ if (rate->flags & IEEE80211_TX_RC_SHORT_GI)
+ stat.enc_flags |= RX_ENC_FLAG_SHORT_GI;
+
+ stat.rate_idx = rate->idx;
+ if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
+ stat.encoding = RX_ENC_VHT;
+ stat.rate_idx = ieee80211_rate_get_vht_mcs(rate);
+ stat.nss = ieee80211_rate_get_vht_nss(rate);
+ } else if (rate->flags & IEEE80211_TX_RC_MCS) {
+ stat.encoding = RX_ENC_HT;
+ } else {
+ stat.encoding = RX_ENC_LEGACY;
+ }
+
+ return ieee80211_calc_rx_airtime(hw, &stat, len);
+}
+
+u32 ieee80211_calc_tx_airtime(struct ieee80211_hw *hw,
+ struct ieee80211_tx_info *info,
+ int len)
+{
+ u32 duration = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(info->status.rates); i++) {
+ struct ieee80211_tx_rate *rate = &info->status.rates[i];
+ u32 cur_duration;
+
+ cur_duration = ieee80211_calc_tx_airtime_rate(hw, rate,
+ info->band, len);
+ if (!cur_duration)
+ break;
+
+ duration += cur_duration * rate->count;
+ }
+
+ return duration;
+}
+EXPORT_SYMBOL_GPL(ieee80211_calc_tx_airtime);
+
+u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif,
+ struct ieee80211_sta *pubsta,
+ int len)
+{
+ struct ieee80211_supported_band *sband;
+ struct ieee80211_chanctx_conf *conf;
+ int rateidx, shift = 0;
+ bool cck, short_pream;
+ u32 basic_rates;
+ u8 band = 0;
+ u16 rate;
+
+ len += 38; /* Ethernet header length */
+
+ conf = rcu_dereference(vif->chanctx_conf);
+ if (conf) {
+ band = conf->def.chan->band;
+ shift = ieee80211_chandef_get_shift(&conf->def);
+ }
+
+ if (pubsta) {
+ struct sta_info *sta = container_of(pubsta, struct sta_info,
+ sta);
+
+ return ieee80211_calc_tx_airtime_rate(hw,
+ &sta->tx_stats.last_rate,
+ band, len);
+ }
+
+ if (!conf)
+ return 0;
+
+ /* No station to get latest rate from, so calculate the worst-case
+ * duration using the lowest configured basic rate.
+ */
+ sband = hw->wiphy->bands[band];
+
+ basic_rates = vif->bss_conf.basic_rates;
+ short_pream = vif->bss_conf.use_short_preamble;
+
+ rateidx = basic_rates ? ffs(basic_rates) - 1 : 0;
+ rate = sband->bitrates[rateidx].bitrate << shift;
+ cck = sband->bitrates[rateidx].flags & IEEE80211_RATE_MANDATORY_B;
+
+ return ieee80211_calc_legacy_rate_duration(rate, short_pream, cck, len);
+}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 05406e9c05b3..225ea4e3cd76 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -2249,6 +2249,10 @@ const char *ieee80211_get_reason_code_string(u16 reason_code);
extern const struct ethtool_ops ieee80211_ethtool_ops;
+u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif,
+ struct ieee80211_sta *pubsta,
+ int len);
#ifdef CONFIG_MAC80211_NOINLINE
#define debug_noinline noinline
#else
--
2.24.0.rc1.363.gb1bccd3e3d-goog
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 <[email protected]>
[ Toke: Keep API to set pending airtime internal, fix nits in commit msg ]
Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
---
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)
{
--
2.24.0.rc1.363.gb1bccd3e3d-goog
I have tested it with Toke's patch "[PATCH v6 4/4] mac80211: Use
Airtime-based Queue Limits (AQL) on packet dequeue", but didn't
include it here, as it is self contained and Toke has plan to update
it.
The platform (QCA9984) used in my test doesn't support 802.11ax, so I
was not able to test the HE mode support added in v7 update of "Import
airtime calculation code from mt76" from Toke.
On Thu, Nov 14, 2019 at 5:48 PM Kan Yan <[email protected]> wrote:
>
> This patch series port the Airtime Queue Limits concept from the out-of-tree
> ath10k implementation[0] to mac80211. This version takes my patch to do the
> throttling in mac80211, and replaces the driver API with the mechanism from
> Toke's series, which instead calculated the expected airtime at dequeue time
> inside mac80211, storing it in the SKB cb field.
>
> This version has been tested on QCA9984 platform.
>
> [0] https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1703105/7
>
> Changelog:
>
> v8:
> - Includes Toke's v7 version of "mac80211: Import airtime calculation code from mt76"
> - Don't clobber sta's customized queue limit when configuring the default via debugfs
> - Fix a racing condition when reset aql_tx_pending.
>
> v7:
> - Fix aql_total_pending_airtime underflow due to insufficient locking.
>
> v6:
> - Fix sta lookup in ieee80211_report_used_skb().
> - Move call to ieee80211_sta_update_pending_airtime() to a bit later in
> __ieee80211_tx_status()
> v5:
> - Add missing export of ieee80211_calc_rx_airtime() and make
> ieee80211_calc_tx_airtime_rate() static (kbuildbot).
> - Use skb_get_queue_mapping() to get the AC from the skb.
> - Take basic rate configuration for the BSS into account when calculating
> multicast rate.
> v4:
> - Fix calculation that clamps the maximum airtime to fit into 10 bits
> - Incorporate Rich Brown's nits for the commit message in Kan's patch
> - Add fewer local variables to ieee80211_tx_dequeue()
> v3:
> - Move the tx_time_est field so it's shared with ack_frame_id, and use units
> of 4us for the value stored in it.
> - Move the addition of the Ethernet header size into ieee80211_calc_expected_tx_airtime()
> v2:
> - Integrate Kan's approach to airtime throttling.
> - Hopefully fix the cb struct alignment on big-endian architectures.
>
>
>
> Kan Yan (1):
> mac80211: Implement Airtime-based Queue Limit (AQL)
>
> Toke Høiland-Jørgensen (1):
> mac80211: Import airtime calculation code from mt76
>
> include/net/cfg80211.h | 7 +
> include/net/mac80211.h | 41 +++
> net/mac80211/Makefile | 3 +-
> net/mac80211/airtime.c | 597 +++++++++++++++++++++++++++++++++++++
> net/mac80211/debugfs.c | 85 ++++++
> net/mac80211/debugfs_sta.c | 43 ++-
> net/mac80211/ieee80211_i.h | 8 +
> net/mac80211/main.c | 10 +-
> net/mac80211/sta_info.c | 38 +++
> net/mac80211/sta_info.h | 8 +
> net/mac80211/tx.c | 47 ++-
> 11 files changed, 872 insertions(+), 15 deletions(-)
> create mode 100644 net/mac80211/airtime.c
>
> --
> 2.24.0.rc1.363.gb1bccd3e3d-goog
>
On Thu, Nov 14, 2019 at 6:04 PM Kan Yan <[email protected]> wrote:
>
> I have tested it with Toke's patch "[PATCH v6 4/4] mac80211: Use
> Airtime-based Queue Limits (AQL) on packet dequeue", but didn't
> include it here, as it is self contained and Toke has plan to update
> it.
>
> The platform (QCA9984) used in my test
I do keep hoping for pretty pictures. Got any? :-P
> doesn't support 802.11ax, so I
> was not able to test the HE mode support added in v7 update of "Import
> airtime calculation code from mt76" from Toke.
Is there an ax QCAXXXX platform, m.2 card, or mini-pci card worth
testing at this point?
How are they handling mu-mimo?
I have a round of tests scheduled for intel's ax200 chips, soon. Not sure
what, if any, of this new work might apply.
> On Thu, Nov 14, 2019 at 5:48 PM Kan Yan <[email protected]> wrote:
> >
> > This patch series port the Airtime Queue Limits concept from the out-of-tree
> > ath10k implementation[0] to mac80211. This version takes my patch to do the
> > throttling in mac80211, and replaces the driver API with the mechanism from
> > Toke's series, which instead calculated the expected airtime at dequeue time
> > inside mac80211, storing it in the SKB cb field.
> >
> > This version has been tested on QCA9984 platform.
> >
> > [0] https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1703105/7
> >
> > Changelog:
> >
> > v8:
> > - Includes Toke's v7 version of "mac80211: Import airtime calculation code from mt76"
> > - Don't clobber sta's customized queue limit when configuring the default via debugfs
> > - Fix a racing condition when reset aql_tx_pending.
> >
> > v7:
> > - Fix aql_total_pending_airtime underflow due to insufficient locking.
> >
> > v6:
> > - Fix sta lookup in ieee80211_report_used_skb().
> > - Move call to ieee80211_sta_update_pending_airtime() to a bit later in
> > __ieee80211_tx_status()
> > v5:
> > - Add missing export of ieee80211_calc_rx_airtime() and make
> > ieee80211_calc_tx_airtime_rate() static (kbuildbot).
> > - Use skb_get_queue_mapping() to get the AC from the skb.
> > - Take basic rate configuration for the BSS into account when calculating
> > multicast rate.
> > v4:
> > - Fix calculation that clamps the maximum airtime to fit into 10 bits
> > - Incorporate Rich Brown's nits for the commit message in Kan's patch
> > - Add fewer local variables to ieee80211_tx_dequeue()
> > v3:
> > - Move the tx_time_est field so it's shared with ack_frame_id, and use units
> > of 4us for the value stored in it.
> > - Move the addition of the Ethernet header size into ieee80211_calc_expected_tx_airtime()
> > v2:
> > - Integrate Kan's approach to airtime throttling.
> > - Hopefully fix the cb struct alignment on big-endian architectures.
> >
> >
> >
> > Kan Yan (1):
> > mac80211: Implement Airtime-based Queue Limit (AQL)
> >
> > Toke Høiland-Jørgensen (1):
> > mac80211: Import airtime calculation code from mt76
> >
> > include/net/cfg80211.h | 7 +
> > include/net/mac80211.h | 41 +++
> > net/mac80211/Makefile | 3 +-
> > net/mac80211/airtime.c | 597 +++++++++++++++++++++++++++++++++++++
> > net/mac80211/debugfs.c | 85 ++++++
> > net/mac80211/debugfs_sta.c | 43 ++-
> > net/mac80211/ieee80211_i.h | 8 +
> > net/mac80211/main.c | 10 +-
> > net/mac80211/sta_info.c | 38 +++
> > net/mac80211/sta_info.h | 8 +
> > net/mac80211/tx.c | 47 ++-
> > 11 files changed, 872 insertions(+), 15 deletions(-)
> > create mode 100644 net/mac80211/airtime.c
> >
> > --
> > 2.24.0.rc1.363.gb1bccd3e3d-goog
> >
> _______________________________________________
> Make-wifi-fast mailing list
> [email protected]
> https://lists.bufferbloat.net/listinfo/make-wifi-fast
--
Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740
Kan Yan <[email protected]> writes:
> 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 <[email protected]>
> [ Toke: Keep API to set pending airtime internal, fix nits in commit msg ]
> Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
> ---
[...]
> + if (sta) {
> + atomic_sub(tx_airtime, &sta->airtime[ac].aql_tx_pending);
> + tx_pending = atomic_read(&sta->airtime[ac].aql_tx_pending);
This is still racy, since you're splitting it over two calls; you'll
need to use atomic_sub_return() instead.
I figure we've converged now to the point where it actually makes sense
to collect everything back into a single series; so I can just fix this
and re-send the full series.
> + 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);
This could still fail if there's a concurrent modification (and you're
not checking the return of the cmpxchg). But at least it won't clobber
any updated value, so I guess that is acceptable since we're in "should
never happen" territory here :)
-Toke
> > + if (sta) {
> > + atomic_sub(tx_airtime, &sta->airtime[ac].aql_tx_pending);
> > + tx_pending = atomic_read(&sta->airtime[ac].aql_tx_pending);
> This is still racy, since you're splitting it over two calls; you'll
> need to use atomic_sub_return() instead.
> I figure we've converged now to the point where it actually makes sense
> to collect everything back into a single series; so I can just fix this
> and re-send the full series.
Thanks for help fixing this. Yes, atomic_sub_return() is better.
>
>
> > + 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);
> This could still fail if there's a concurrent modification (and you're
> not checking the return of the cmpxchg). But at least it won't clobber
> any updated value, so I guess that is acceptable since we're in "should
> never happen" territory here :)
I did this on purpose since I really don't like adding a loop to retry
here. If aql_tx_pending indeed goes negative (should never happens and
we got WARN_ONCE() to catch it) and the subsequent atomic_cmpxchg()
failed (rare racing occasions), it is still ok. In this case,
aql_tx_pending carries a negative offset and will be reset in one of
the calls to ieee80211_sta_update_pending_airtime() later.
aql_tx_pending being negative doesn't have much side-effects, such as
causing txq stuck.
On Fri, Nov 15, 2019 at 4:56 AM Toke Høiland-Jørgensen <[email protected]> wrote:
>
> Kan Yan <[email protected]> writes:
>
> > 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 <[email protected]>
> > [ Toke: Keep API to set pending airtime internal, fix nits in commit msg ]
> > Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
> > ---
> [...]
>
> > + if (sta) {
> > + atomic_sub(tx_airtime, &sta->airtime[ac].aql_tx_pending);
> > + tx_pending = atomic_read(&sta->airtime[ac].aql_tx_pending);
>
> This is still racy, since you're splitting it over two calls; you'll
> need to use atomic_sub_return() instead.
>
> I figure we've converged now to the point where it actually makes sense
> to collect everything back into a single series; so I can just fix this
> and re-send the full series.
>
> > + 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);
>
> This could still fail if there's a concurrent modification (and you're
> not checking the return of the cmpxchg). But at least it won't clobber
> any updated value, so I guess that is acceptable since we're in "should
> never happen" territory here :)
>
> -Toke
>