Latency spikes in rtw89

Latency spikes in rtw89

[Jeff Clay]

Hi, I am using the rtw89 driver for Realtek 8852AE in my Lenovo T14
AMD Gen2. I have obtained and installed this driver from source at
https://github.com/lwfinger/rtw89/tree/main I am having an issue where
the latency during a ping test to hosts on my LAN spikes to 200ms or
above. According to lwfinger, this is known and acceptable
https://github.com/lwfinger/rtw89/issues/85  However, I am hoping I
may be able to work with you to resolve this issue as a tester.

RE: Latency spikes in rtw89

[Pkshih]

> -----Original Message-----
> From: Jeff Clay <jeffclay@gmail.com>
> Sent: Wednesday, December 1, 2021 3:16 AM
> To: linux-wireless@vger.kernel.org
> Subject: Latency spikes in rtw89
> 
> Hi, I am using the rtw89 driver for Realtek 8852AE in my Lenovo T14
> AMD Gen2. I have obtained and installed this driver from source at
> https://github.com/lwfinger/rtw89/tree/main I am having an issue where
> the latency during a ping test to hosts on my LAN spikes to 200ms or
> above. According to lwfinger, this is known and acceptable
> https://github.com/lwfinger/rtw89/issues/85  However, I am hoping I
> may be able to work with you to resolve this issue as a tester.

We know this, and it is due to power saving; i.e. tradeoff between
latency and power saving. We are thinking how to improve it entirely.

--
Ping-Ke

Re: Latency spikes in rtw89

[Jeff Clay]

Thank you for the information. Would the issue persist if I were to
disable wireless power management?

On Tue, Nov 30, 2021 at 7:33 PM Pkshih <pkshih@realtek.com> wrote:
>
>
> > -----Original Message-----
> > From: Jeff Clay <jeffclay@gmail.com>
> > Sent: Wednesday, December 1, 2021 3:16 AM
> > To: linux-wireless@vger.kernel.org
> > Subject: Latency spikes in rtw89
> >
> > Hi, I am using the rtw89 driver for Realtek 8852AE in my Lenovo T14
> > AMD Gen2. I have obtained and installed this driver from source at
> > https://github.com/lwfinger/rtw89/tree/main I am having an issue where
> > the latency during a ping test to hosts on my LAN spikes to 200ms or
> > above. According to lwfinger, this is known and acceptable
> > https://github.com/lwfinger/rtw89/issues/85  However, I am hoping I
> > may be able to work with you to resolve this issue as a tester.
>
> We know this, and it is due to power saving; i.e. tradeoff between
> latency and power saving. We are thinking how to improve it entirely.
>
> --
> Ping-Ke
>

Re: Latency spikes in rtw89

[Larry Finger]

On 12/1/21 08:48, Jeff Clay wrote:
> Thank you for the information. Would the issue persist if I were to
> disable wireless power management?

That is an easy experiment to try. Use the "disable_ps_mode=y' module option for 
rtw89core.

Larry

RE: Latency spikes in rtw89

[Pkshih]

> -----Original Message-----
> From: Larry Finger <larry.finger@gmail.com> On Behalf Of Larry Finger
> Sent: Thursday, December 2, 2021 1:39 AM
> To: Jeff Clay <jeffclay@gmail.com>; Pkshih <pkshih@realtek.com>
> Cc: linux-wireless@vger.kernel.org
> Subject: Re: Latency spikes in rtw89
> 
> On 12/1/21 08:48, Jeff Clay wrote:
> > Thank you for the information. Would the issue persist if I were to
> > disable wireless power management?
> 
> That is an easy experiment to try. Use the "disable_ps_mode=y' module option for
> rtw89core.
> 

Another way is to use 'iw wlan0 set power_save off'.

--
Ping-Ke

Re: Latency spikes in rtw89

[Jeff Clay]

Setting "options rtw89core disable_ps_mode=Y" in
/etc/modprobe.d/rtw89.conf didn't help.

On Wed, Dec 1, 2021 at 11:39 AM Larry Finger <Larry.Finger@lwfinger.net> wrote:
>
> On 12/1/21 08:48, Jeff Clay wrote:
> > Thank you for the information. Would the issue persist if I were to
> > disable wireless power management?
>
> That is an easy experiment to try. Use the "disable_ps_mode=y' module option for
> rtw89core.
>
> Larry
>

Re: Latency spikes in rtw89

[Jeff Clay]

Thank you! That has resolved the issue.

On Wed, Dec 1, 2021 at 6:16 PM Pkshih <pkshih@realtek.com> wrote:
>
>
> > -----Original Message-----
> > From: Larry Finger <larry.finger@gmail.com> On Behalf Of Larry Finger
> > Sent: Thursday, December 2, 2021 1:39 AM
> > To: Jeff Clay <jeffclay@gmail.com>; Pkshih <pkshih@realtek.com>
> > Cc: linux-wireless@vger.kernel.org
> > Subject: Re: Latency spikes in rtw89
> >
> > On 12/1/21 08:48, Jeff Clay wrote:
> > > Thank you for the information. Would the issue persist if I were to
> > > disable wireless power management?
> >
> > That is an easy experiment to try. Use the "disable_ps_mode=y' module option for
> > rtw89core.
> >
>
> Another way is to use 'iw wlan0 set power_save off'.
>
> --
> Ping-Ke
>