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From: Pkshih <pkshih@realtek.com>
To: "jprvita@gmail.com" <jprvita@gmail.com>,
	"Larry.Finger@lwfinger.net" <Larry.Finger@lwfinger.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"jprvita@endlessm.com" <jprvita@endlessm.com>,
	"Birming Chiu" <birming@realtek.com>,
	"drake@endlessm.com" <drake@endlessm.com>,
	Chaoming_Li <chaoming_li@realsil.com.cn>,
	"kvalo@codeaurora.org" <kvalo@codeaurora.org>,
	莊彥宣 <yhchuang@realtek.com>,
	"derosier@gmail.com" <derosier@gmail.com>,
	"Steven Ting" <steventing@realtek.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux@endlessm.com" <linux@endlessm.com>,
	Shaofu <shaofu@realtek.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: Re: RTL8723BE performance regression
Date: Wed, 2 May 2018 05:58:42 +0000	[thread overview]
Message-ID: <1525240713.3735.3.camel@realtek.com> (raw)
In-Reply-To: <5B2DA6FDDF928F4E855344EE0A5C39D13BEC14C0@RTITMBSV07.realtek.com.tw>

On Wed, 2018-05-02 at 05:44 +0000, Pkshih wrote:
> 
> > -----Original Message-----
> > From: João Paulo Rechi Vita [mailto:jprvita@gmail.com]
> > 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@endlessm.c
> om
> > Subject: Re: RTL8723BE performance regression
> > 
> > On Tue, Apr 3, 2018 at 7:51 PM, Larry Finger <Larry.Finger@lwfinger.net> 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@lwfinger.net>
> > >> 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.
> 

Please pay attention to cold reboot once ant_sel is changed.

  reply	other threads:[~2018-05-02  5:59 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-04  1:51 João Paulo Rechi Vita
2018-04-04  2:28 ` Larry Finger
2018-04-04  2:37   ` João Paulo Rechi Vita
2018-04-04  2:51     ` Larry Finger
2018-05-01 22:41       ` João Paulo Rechi Vita
2018-05-01 22:46         ` [RFC PATCH 1/3] rtlwifi: btcoex: Don't init antenna position to main port João Paulo Rechi Vita
2018-05-01 22:46           ` [RFC PATCH 2/3] Revert "rtlwifi: fill FW version and subversion" João Paulo Rechi Vita
2018-05-01 22:46           ` [RFC PATCH 3/3] rtlwifi: btcoex: Always use 2ant-functions for RTL8723BE João Paulo Rechi Vita
2018-05-02  5:44         ` RTL8723BE performance regression Pkshih
2018-05-02  5:58           ` Pkshih [this message]
2018-05-07 21:49             ` João Paulo Rechi Vita
2018-05-08  8:37               ` Pkshih
2018-05-09 20:33                 ` João Paulo Rechi Vita
2018-05-14  2:50                   ` Pkshih
2018-04-04 14:54 ` Steve deRosier

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