Bug 198677

Summary:	iwlwifi: 9260: Tx speed is slow on 5GHz
Product:	Drivers	Reporter:	AceLan Kao (acelan)
Component:	network-wireless	Assignee:	DO NOT USE - assign "network-wireless-intel" component instead (linuxwifi)
Status:	CLOSED INVALID
Severity:	normal	CC:	luca
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	4.15-rc10	Subsystem:
Regression:	No	Bisected commit-id:

Description AceLan Kao 2018-02-05 06:52:07 UTC

From my observation, the speed issue only happens on tx.

I use speedtest-cli the measure internet speed
   Download/Upload = 70.09 Mbits/s / 1.87 Mbit/s

And use iperf to measure intranet speed with a server connected over ethernet cable
   Download/Upload = 78.6 Mbits/s / 1.51 Mbit/s

The upload bandwidth we have is the same the download bandwidth, so both results are bad.

acelan@u-Kabylake-Client-platform ~ % speedtest-cli 
Retrieving speedtest.net configuration...
Testing from Taiwan Internet Gateway (175.41.48.77)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Asia Pacific Telecom (Taipei) [3.82 km]: 1.541 ms
Testing download speed................................................................................
Download: 78.09 Mbit/s
Testing upload speed................................................................................................
Upload: 1.87 Mbit/s

acelan@u-Kabylake-Client-platform ~ % iperf -c 10.101.46.219 -er                                                         
------------------------------------------------------------
Server listening on TCP port 5001 with pid 27531
Read buffer size: 1.44 KByte
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 10.101.46.219, TCP port 5001 with pid 27531
Write buffer size:  128 KByte
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  5] local 10.101.46.137 port 53328 connected with 10.101.46.219 port 5001
[ ID] Interval        Transfer    Bandwidth       Write/Err  Rtry    Cwnd/RTT
[  5] 0.00-13.16 sec  2.38 MBytes  1.51 Mbits/sec  1/0         86       15K/137450 us
[  4] local 10.101.46.137 port 5001 connected with 10.101.46.219 port 51230
[ ID] Interval        Transfer    Bandwidth       Reads   Dist(bin=0.2K)
[  4] 0.00-10.21 sec  95.8 MBytes  78.6 Mbits/sec  69327    212:96:139:89:972:364:197:67258

Comment 1 AceLan Kao 2018-02-08 07:30:42 UTC

More findings, using iperf to measure the speed for 60 seconds and report status
every 10 seconds. The Tx speed is very unstable in the reports every 10 seconds, sometimes Tx speed is upto 50+MBits/sec, and sometimes it's slower than 1 MBits/sec.
Card ID - CN-01RKV5-ITG00-781-02PK-X00
       iperf(-t60 -i10) 1.26 1.78 0.419 1.15 16.7 56.8 MBits/sec
       speedtest-cli ~30 MBits/sec
CARD ID - CN-01RKV5-ITG00-781-01Q9-X00
       iperf(-t60 -i10) 54.1 22.8 13.7 2.10 1.47 5.56 MBits/sec
       speedtest-cli ~30 MBits/sec

The iperf command I use is
   iperf -c 10.101.46.219 -r -t60 -i10
And on a machine with ethernet cable connected(ip:10.101.46.219) runs
   iperf -s

Comment 2 Luca Coelho 2018-02-10 07:33:32 UTC

AceLan, can you provide a sniffer capture of this problem?

Comment 3 AceLan Kao 2018-02-27 02:34:59 UTC

Sorry for not updating info here, this issue is result from our bad wifi AP, not Intel 9260.
We've tried the test on 3 different wifi APs, and we only can reproduce this issue on one AP, other 2 APs are not infected.

Comment 4 Emmanuel Grumbach 2018-02-27 06:56:59 UTC

what is the bad AP?