#22445: Regression CC vs BB release: Low WiFi speed when increasing coverage
class
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Reporter: xback | Owner: developers
Type: defect | Status: new
Priority: normal | Milestone:
Component: packages | Version: Chaos Calmer 15.05
Keywords: ath9k,mac80211,minstrel |
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Synopsis:
Chaoscalmer has a lot less wifi bandwidth when coverage class is
increased.
Even when 2 devices are only a few meters apart.
In Barrierbreaker release, the rates were a lot higher in this usecase.
When doing Iperf benchmarks (~ 30 sec);
- The barrierbreaker release is able to hit ~53Mbit from start to finish
- Chaoscalmer starts at ~6Mbit/s, than slowly goes up to ~20Mbit/s. But
starts at 6 again when the test is repeated.
Following setup:
- 2 identical devices
- IBSS mode using wpa_supplicant WPA2
- 2m apart
- Free 5GHz channel (confirmed using spectrum analyzer)
- HT20 (HT40 has same behaviour)
- Coverage class 32 (up to 14400m)
Iperf using BarrierBreaker build: ~52Mbit/s
Iperf using ChaosCalmer build: ~6Mbit/s
- Coverage class 16 (up to 7200m)
Iperf using BarrierBreaker build: ~53Mbit/s
Iperf using ChaosCalmer build: ~12Mbit/s
- Dynack
Iperf using BarrierBreaker build: ~55Mbit/s
Iperf using ChaosCalmer build: ~53Mbit/s
Steps I tested to identify the issue without success:
- Upgraded wpa_supplicant to latest trunk
- Checked ath9k code hw.c & recv.c (Acktime, slottime, etc. But code
doesnt differ between BB and CC)
- Patches deleted: (in kernel/mac80211/patches)
--> 326-ath9k-make-NF-load-complete-quickly-and-reliably.patch
--> 330-mac80211-minstrel-Change-expected-throughput-unit-ba.patch
--> 334-mac80211-fix-wiphy-supported_band-access.patch
--> 335-mac80211-minstrel_ht-set-A-MSDU-tx-limits-based-on-s.patch
--> 336-mac80211-minstrel_ht-set-default-tx-aggregation-time.patch
--> 337-mac80211-minstrel_ht-fix-a-logic-error-in-RTS-CTS-ha.patch
--> 343-mac80211-minstrel_ht-improve-sample-rate-skip-logic.patch
Only part in the chain that I still need to check:
- Minstrel_ht
If more information is required, please let me know.
Thanks,
Koen
--
Ticket URL: <https://dev.openwrt.org/ticket/22445>
OpenWrt <http://openwrt.org>
Opensource Wireless Router Technology
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