Apple Catalina Appears to Introduce Massive Jitter

Thu Oct 29 12:28:49 UTC 2020

Ah yes, an example of what I am seeing:

Marks-MacBook-Pro.local (172.16.0.239) 2020-10-29T14:28:27+0200
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
Packets               Pings
  Host Loss%   Snt   Last   Avg  Best  Wrst StDev
  1. 172.16.0.254 0.8%   126    3.9  34.7   2.5 232.1  54.9

Mark.

On 10/29/20 14:07, Mark Tinka wrote:
> Hi all.
>
> I've been on High Sierra for several years now due to a limitation 
> with an app that couldn't deal with Apple's latest rounds of system 
> permissions since Mojave. Eventually, I gave up on waiting for them to 
> fix it and upgraded my older Butterfly keyboard laptop to Catalina 4 
> weeks ago.
>
> At the same time, I picked up the new Magic keyboard laptop 2 weeks 
> ago which came with Catalina.
>
> Over the past week, I've been troubleshooting a massive jitter issue 
> on Catalina, just between itself and my home router. For control, I 
> have a Windows PC (tower-top) using a wireless adapter to connect to 
> my home network. That has no jitter at all.
>
> I have noticed as much as 300ms+ jitter on Catalina.
>
> I then asked a few friends around the world to run tests for me on 
> their own Catalina installations to their local router over wi-fi, and 
> the results are the same. Jitter so high that what should be a 1ms - 
> 5ms latency can (for a short period) jump to 200ms+, 300ms+, 400ms+.
>
> On the off-chance that it is an issue with the new wireless chips on 
> the later MacBook models, one of my friends tested the same on a 2013 
> MacBook Pro running a beta version of Big Sur. Same story!
>
> Another friend in South East Asia, testing on a 2018 13-inch MacBook 
> Pro running Catalina, also had the same issue.
>
> A Google search suggests that this is some known issue since Mojave, 
> to do with Location Services, and some other apps, in a 
> non-deterministic way:
>
> https://apple.stackexchange.com/questions/263638/macbook-pro-experiencing-ping-spikes-to-local-router
>
> For me, even after disabling all or some Location Services features, 
> the problem remains.
>
> Is anyone else seeing this on their Catalina Mac's while on wi-fi? If 
> so, does anyone know what's going on here?
>
> Ideally, this wouldn't matter if it was just a cosmetic issue - but I 
> do actually see physical impact to performance of network access 
> to/from the laptop, which has all the hallmarks of high jitter and/or 
> packet loss.
>
> An app like Zoom, which can display network performance data for a 
> session in real-time, does indicate nominal packet loss for audio and 
> video on this device, while other devices on the same WLAN are happy.
>
> Thoughts?
>
> Mark.

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