-----Original Message----- From: Georgiewskiy Yuriy [mailto:bottleman@xxxxxxxxxx] Sent: Monday, December 03, 2012 9:45 AM To: Chaoxing Lin Cc: linux-wireless@xxxxxxxxxxxxxxx Subject: RE: help: 802.11s bad performance with 802.11n enabled On 2012-12-03 14:37 -0000, Chaoxing Lin wrote linux-wireless@xxxxxxxxxxxxxxx: CL>After a lot of experiments, here are various problems observed. CL> CL>1. The "Fail to stop Tx DMA" related issue plays a role. But not the major part. It accounts for about 3% of packet loss in my testbed. CL>Is anyone looking at this issue? This issue is now very easy to recreate. GY>>In my case it much more than 3%. When I say 3% loss due to "Tx DMA", it's measured by eliminate other factors as much as possible (turning off aggregation, etc.) Below is the number from 3-day continuous test. During this 3-day test, "Fail to stop Tx DMA" happens once a while on various nodes. CLIN network activity/stability monitoring system Total targets: 6 Total instability monitored: 3221 192.168.5.103 ICMP Tx 5899087 Rx 5883235 Seq=846 OutOfOrder 427 Pkt loss 15852(0.27%) RTT min/avg/max = 55.0/57.9/11580.0 ms 192.168.5.104 ICMP Tx 5899087 Rx 5721023 Seq=846 OutOfOrder 121213 Pkt loss 178064(3.02%) RTT min/avg/max = 54.0/57.7/9032.0 ms 192.168.5.111 ICMP Tx 5899087 Rx 5726094 Seq=846 OutOfOrder 164950 Pkt loss 172993(2.93%) RTT min/avg/max = 54.0/59.0/9421.0 ms 192.168.5.113 ICMP Tx 5899087 Rx 5894984 Seq=846 OutOfOrder 686 Pkt loss 4103(0.07%) RTT min/avg/max = 54.0/58.0/11524.0 ms 192.168.5.115 ICMP Tx 5899087 Rx 5869967 Seq=846 OutOfOrder 66782 Pkt loss 29120(0.49%) RTT min/avg/max = 54.0/67.7/11801.0 ms 192.168.5.147 ICMP Tx 5899087 Rx 5899086 Seq=846 OutOfOrder 0 Pkt loss 1(0.00%) RTT min/avg/max = 0.0/54.0/110.0 ms Bad Packets: 0 short pkt, 3217664 not-my-echo, 0 not-echo-reply, 0 unknown sender Application Starts: Thu Dec 6 13:59:58 2012 Current Time: Mon Dec 10 08:50:34 2012 Notes: 1. ignore the big numbers in "outoforder" column. When ICMP sequence number is about to overflow (65535), if the last few packets (e.g. ICMP sn.65535) get lost, all packets after overflow will be counted as "outoforder". 2. if anyone is interested in the test tool I used in this test, it's here http://sites.google.com/site/ebaylinkan5709pictures/files-to-share/clinmonitor.gz It's an executable running on any 32-bit Linux. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
