On 04/21/2015 04:07 PM, Shu, Nick wrote: > Hi, Ben: > The data packet do go through the wifi interface twice, so I times 2. > Its hard to put DUT into the chamber, cause its too big. > I'm using your patched driver and firmware, that disabled HW encryption, so > you said this will add CPU load? > Our application can be set to run traffic in one direction, so I will test > again to check the throughout in downlink, uplink, and bidirection for > comparison. > Will also try different AP, NetGear 1900 and Asus one.
In general, bi-directional traffic on wifi is a lot slower than uni-directional, even if you add up both directions in bi-directional traffic. I think this is mostly because the AP and station radios contend for airtime, and you end up taking less advantage of block-acks and A-MPDUS. Maybe more retransmits and backoffs too.. Maybe others will have a better idea. Disabling HW encryption makes the CPU do the decryption, so yeah, that is CPU intensive. 'perf top' or similar should show your cpu usage hotspots. Thanks, Ben > > Thanks! > Nick > ________________________________________ > From: Ben Greear [[email protected]] > Sent: Tuesday, April 21, 2015 4:17 PM > To: Shu, Nick > Cc: [email protected] > Subject: Re: Question about ath10k throughput > > On 04/21/2015 02:59 PM, Shu, Nick wrote: >> Thanks, Ben: >> We use our test application to generate traffic (TCP or UDP), sending from >> wifi NIC (ONLY 1 CLIENT, not multiple vStas). RF cables are used to connect >> from NIC antenna port (x3) to Cisco AP (model#3702E) antenna port (AP is >> placed inside an isolation chamber). Scan results for that AP shows the >> signal strength is -18 dBm (strong enough). >> AP is connected back to test server through Ethernet cable, then Network >> host is route back the data packet to test application. >> So the data throughput is calculated as: number of bytes * 2 (round trip) * >> 8 = Mbps. >> >> So far, we can only get like 400-500 Mbps for UDP. >> Should we set AP to open? Without encryption? > > I don't see why you do the 2x to get 'round-trip'...I think for issues related > to wifi throughput, just talk about the amount of data flowing across the > wifi network interface itself. > > Receiving on a station (download), when using CT firmware and with sw-crypt > enabled, > does decryption on the CPU, and this is normally a CPU bound issue at around > 500Mbps even on expensive E5 processors. > > Upload uses HW encryption, so should run faster with modest host CPU usage. > > I would try Open auth testing when verifying wifi throughput..then compare > that > against your encrypted throughput to see if you are CPU bound (or, at least > not RF bound). > > If you are doing true TCP protocol, then it will back off on drops (and > require > TCP ack frames and so forth). You will get quite a bit more bulk throughput > with UDP. > > I would also try multiple different APs to try to find the best one. > > Big expensive names on the AP don't always mean so much for basic throughput > tests in our experience. > > Having the AP inside an isolation chamber is helpful, but you really > need your station system inside a chamber as well for a truly isolated test, > otherwise > the station system may be picking up interference that causes lost frames > and so forth (and AP might pick up similar interference through cables > connected to your test equipment). > > Thanks, > Ben > > > -- > Ben Greear <[email protected]> > Candela Technologies Inc http://www.candelatech.com > > Spirent Communications e-mail confidentiality. > ------------------------------------------------------------------------ > This e-mail contains confidential and / or privileged information belonging > to Spirent Communications plc, its affiliates and / or subsidiaries. If you > are not the intended recipient, you are hereby notified that any disclosure, > copying, distribution and / or the taking of any action based upon reliance > on the contents of this transmission is strictly forbidden. If you have > received this message in error please notify the sender by return e-mail and > delete it from your system. > > Spirent Communications plc > Northwood Park, Gatwick Road, Crawley, West Sussex, RH10 9XN, United Kingdom. > Tel No. +44 (0) 1293 767676 > Fax No. +44 (0) 1293 767677 > > Registered in England Number 470893 > Registered at Northwood Park, Gatwick Road, Crawley, West Sussex, RH10 9XN, > United Kingdom. > > Or if within the US, > > Spirent Communications, > 27349 Agoura Road, Calabasas, CA, 91301, USA. > Tel No. 1-818-676- 2300 > -- Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com _______________________________________________ ath10k mailing list [email protected] http://lists.infradead.org/mailman/listinfo/ath10k
