> -----Original Message----- > From: João Paulo Rechi Vita [mailto:jprvita@xxxxxxxxx] > Sent: Wednesday, May 02, 2018 6:41 AM > To: Larry Finger > Cc: Steve deRosier; 莊彥宣; Pkshih; Birming Chiu; Shaofu; Steven Ting; Chaoming_Li; Kalle Valo; > linux-wireless; Network Development; LKML; Daniel Drake; João Paulo Rechi Vita; linux@xxxxxxxxxxxx > Subject: Re: RTL8723BE performance regression > > On Tue, Apr 3, 2018 at 7:51 PM, Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote: > > On 04/03/2018 09:37 PM, João Paulo Rechi Vita wrote: > >> > >> On Tue, Apr 3, 2018 at 7:28 PM, Larry Finger <Larry.Finger@xxxxxxxxxxxx> > >> wrote: > >> > >> (...) > >> > >>> As the antenna selection code changes affected your first bisection, do > >>> you > >>> have one of those HP laptops with only one antenna and the incorrect > >>> coding > >>> in the FUSE? > >> > >> > >> Yes, that is why I've been passing ant_sel=1 during my tests -- this > >> was needed to achieve a good performance in the past, before this > >> regression. I've also opened the laptop chassis and confirmed the > >> antenna cable is plugged to the connector labeled with "1" on the > >> card. > >> > >>> If so, please make sure that you still have the same signal > >>> strength for good and bad cases. I have tried to keep the driver and the > >>> btcoex code in sync, but there may be some combinations of antenna > >>> configuration and FUSE contents that cause the code to fail. > >>> > >> > >> What is the recommended way to monitor the signal strength? > > > > > > The btcoex code is developed for multiple platforms by a different group > > than the Linux driver. I think they made a change that caused ant_sel to > > switch from 1 to 2. At least numerous comments at > > github.com/lwfinger/rtlwifi_new claimed they needed to make that change. > > > > Mhy recommended method is to verify the wifi device name with "iw dev". Then > > using that device > > > > sudo iw dev <dev_name> scan | egrep "SSID|signal" > > > > I have confirmed that the performance regression is indeed tied to > signal strength: on the good cases signal was between -16 and -8 dBm, > whereas in bad cases signal was always between -50 to - 40 dBm. I've > also switched to testing bandwidth in controlled LAN environment using > iperf3, as suggested by Steve deRosier, with the DUT being the only > machine connected to the 2.4 GHz radio and the machine running the > iperf3 server connected via ethernet. > We have new experimental results in commit af8a41cccf8f46 ("rtlwifi: cleanup 8723be ant_sel definition"). You can use the above commit and do the same experiments (with ant_sel=0, 1 and 2) in your side, and then share your results. Since performance is tied to signal strength, you can only share signal strength. Regards PK
