Apple Catalina Appears to Introduce Massive Jitter - SOLVED!

Fri Oct 30 23:53:48 UTC 2020

Heya ! Doug!

Yeah I wouldn’t put this on BT either. On the other hand it seems that whether the scheduler is newreno or cubic that this situation persists pasts my previous suggestions. Seems tho that when you put strain on an upload that the jitter gets considerably worse... 90m out of a 100m link it starts to get to 1000+ms

-- 
 J. Hellenthal

The fact that there's a highway to Hell but only a stairway to Heaven says a lot about anticipated traffic volume.

> On Oct 30, 2020, at 16:59, Doug Barton <dougb at dougbarton.us> wrote:
> I would hesitate to blame BT. I have a macbook pro from ~1 year ago, on Catalina, and I use BT extensively ... mouse, keyboard, and headset. I do have location services trimmed down to just find my mac.
> 
> I ran: ping -c 1000 -i 0.1 <router address>
> 
> 1000 packets transmitted, 998 packets received, 0.2% packet loss
> round-trip min/avg/max/stddev = 1.255/2.378/9.095/0.634 ms
> 
> One thing that may contribute to blaming BT however is if you are using wifi on 2.4G only, and/or preferring it, as BT operates in the same frequency range neighborhood. My macbook is connected using 5G.
> 
> Happy to compare other settings if there is interest.
> 
> Doug
> 
> 
>> On 10/30/20 12:08 PM, Mark Tinka wrote:
>> Hi all.
>> So I may have fixed this for my end, and hopefully others may be able to use the same fix.
>> After a tip from Karl Auerbach and this link:
>> https://developer.apple.com/forums/thread/97805
>> ... I was able to fix the problem by disabling Bluetooth.
>> However, disabling Bluetooth was not enough. I also had to disable all Location Services.
>> After that, I re-enabled Location Services and only allowed for two features:
>>     - NetSpot
>>     - Find My Mac
>> With just those two location services, as well as Bluetooth disabled, I have no more high jitter.
>> App performance like Zoom and Youtube uploads are now crisp, with 0.0% packet loss.
>> So looks like that Bluetooth is a huge problem. Confirmed by opening the "Console" app, and adding "scan" in the filter bar, top right.
>> A peak latency of 13.5ms after 300 packets:
>> Marks-MacBook-Pro.local (172.16.0.239) 2020-10-30T21:06:05+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 0.0%   300    3.1   4.8   2.2  13.5   1.9
>> Mark.
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