Puzzling clock offset spikes
paul at anastrophe.com
Thu Jul 5 16:53:05 UTC 2018
On 7/5/18 09:42, Gary E. Miller wrote:
> Yo Paul!
> On Wed, 4 Jul 2018 18:37:46 -0700
> Paul Theodoropoulos <paul at anastrophe.com> wrote:
>> What changed: I'd poked around with assorted parameters of the "dwc"
>> module, which apparently drives the USB subsystem. It got to where
>> I'd added all of these dwc module options to the /boot/cmdline.txt:
> You are runnning USB on a timekeeping RasPi? I stopped doing that
> when I noticed it wrecked havok with my measurements. Unplug!
I attach a microSD card in a USB adapter in order to perform backups,
but I do only intermittently - every few days to a week or so. I could
probably leave it attached to the ntpVIZ Raspi 1 and rsync over the LAN
though; I should probably do that, then I can back up on a more formal
> Of course the ethernet goes through USB on the RasPi, so minimize
> ethernet usage too.
Latency, jitter, etc, are terrible over wifi, and I have pretty good
wifi. When I monitor the netdata graphs in realtime over the WAN,
there's no visible change to the metrics, and that generates a lot of
https traffic, so I don't think that's it.
That said, latency and jitter were terrible when I first got my raspi 1
a couple of years ago; I've never tried it on the 3, so perhaps wifi on
the raspi 3 might not suffer those issues; I will have to look into
that. It'd be nice to be able to untether the little devil anyway, so I
could easily relocate it elsewhere in the house where ambient temps
might be smoother. I will check it out!
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