2021-11-30 19:17:06

by Jeff Clay

[permalink] [raw]
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.


2021-12-01 01:33:57

by Ping-Ke Shih

[permalink] [raw]
Subject: RE: Latency spikes in rtw89


> -----Original Message-----
> From: Jeff Clay <[email protected]>
> Sent: Wednesday, December 1, 2021 3:16 AM
> To: [email protected]
> 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

2021-12-01 14:49:27

by Jeff Clay

[permalink] [raw]
Subject: Re: Latency spikes in rtw89

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 <[email protected]> wrote:
>
>
> > -----Original Message-----
> > From: Jeff Clay <[email protected]>
> > Sent: Wednesday, December 1, 2021 3:16 AM
> > To: [email protected]
> > 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
>

2021-12-01 17:39:26

by Larry Finger

[permalink] [raw]
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.

Larry


2021-12-02 00:16:17

by Ping-Ke Shih

[permalink] [raw]
Subject: RE: Latency spikes in rtw89


> -----Original Message-----
> From: Larry Finger <[email protected]> On Behalf Of Larry Finger
> Sent: Thursday, December 2, 2021 1:39 AM
> To: Jeff Clay <[email protected]>; Pkshih <[email protected]>
> Cc: [email protected]
> 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

2021-12-02 01:43:30

by Jeff Clay

[permalink] [raw]
Subject: Re: Latency spikes in rtw89

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 <[email protected]> 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
>

2021-12-02 01:46:22

by Jeff Clay

[permalink] [raw]
Subject: Re: Latency spikes in rtw89

Thank you! That has resolved the issue.

On Wed, Dec 1, 2021 at 6:16 PM Pkshih <[email protected]> wrote:
>
>
> > -----Original Message-----
> > From: Larry Finger <[email protected]> On Behalf Of Larry Finger
> > Sent: Thursday, December 2, 2021 1:39 AM
> > To: Jeff Clay <[email protected]>; Pkshih <[email protected]>
> > Cc: [email protected]
> > 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
>