Apple Catalina Appears to Introduce Massive Jitter

Fri Oct 30 06:41:44 UTC 2020

On 10/29/20 20:14, David Curado wrote:

> I was curious, so poked at this... my results from a macbook pro 2019 
> running Catalina 10.15.3
>
> sudo /usr/local/sbin/mtr -r 10.200.200.200
>
> Start: 2020-10-29T14:09:08-0400
> HOST: bos-mp36c                   Loss%   Snt Last   Avg  Best  Wrst StDev
>   1.|-- 10.200.200.200             0.0%    10 11.9  63.7   9.0 340.2 104.1
>
> sudo sysctl net.link.generic.system.hwcksum_tx=0
> net.link.generic.system.hwcksum_tx: 1 -> 0
> sudo sysctl net.link.generic.system.hwcksum_rx=0
> net.link.generic.system.hwcksum_rx: 1 -> 0
> sudo ifconfig en0 -rxcsum
>
> sudo /usr/local/sbin/mtr -r 10.200.200.200
>
> Start: 2020-10-29T14:09:43-0400
> HOST: bos-mp36c                   Loss%   Snt Last   Avg  Best  Wrst StDev
>   1.|-- 10.200.200.200             0.0%    10 19.8  13.6   9.8  20.9   4.5
>
> So, seems to make things better. =-)

I tried it again this morning, on the off-chance that the stars didn't 
align yesterday. Same deal:

sh-3.2# sysctl net.link.generic.system.hwcksum_tx=0
net.link.generic.system.hwcksum_tx: 1 -> 0
sh-3.2# sysctl net.link.generic.system.hwcksum_rx=0
net.link.generic.system.hwcksum_rx: 1 -> 0
sh-3.2# ifconfig en0 -rxcsum

Marks-MacBook-Pro.local (172.16.0.239) 2020-10-30T08:39:44+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%    28    1.9  28.7   1.9 218.9  56.1

Mark.