Apple Catalina Appears to Introduce Massive Jitter

Thu Oct 29 16:05:32 UTC 2020

On the latest Catalina 10.15.7 from a MacBook Air (early 2014) via WiFi 
to Google Wifi Mesh router (only a single unit network):

Over 2.4Ghz through 3 interior walls:
--- 192.168.86.1 ping statistics ---
100 packets transmitted, 100 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 1.440/15.078/213.538/30.541 ms

Over 5Ghz through 1 door:
--- 192.168.86.1 ping statistics ---
100 packets transmitted, 100 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 1.557/24.614/137.233/39.015 ms

This is a real world test with several iPhones, 2.4GHz WiFi only 
cameras, and an iPad being used for zoom (remote school) while running 
these tests. If you were not aware, on a Mac you can hold the Option key 
while clicking on the WiFi icon to see more options as well as more 
information about your current WiFi connection, including the realtime 
Tx rate, channel, and when your Mac is searching for new networks (mine 
does this every few seconds, it seems).

 From an experience perspective, all applications seem to work fine for 
us. Including uploading to YouTube (a regular event as my spouse is a 
teacher) and Zoom/Teams/FaceTime/your teleconference app of choice (used 
by all of us).

--B

On 10/29/2020 7:28 AM, Mark Tinka wrote:
> 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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