Latency jumps to 400000

Hey,
I was just running the latency test for over an hour. The max base jitter stayed at about 10000, but after coming back to the machine it jumped to over 400000.
During this test I was running 5 or 6 instances of glxgears, a flash video on youtube and creating 10GB files with random data from /dev/urandom to stress the machine.
The board I am using is a Baytrail J1900 from Gigabyte with onboard parallel port.

Any ideas what might have happend? Is it save to configure linuxcnc with the max jitter of about 10000?

Did you turn off all power management in the BIOS?
this is very important for minimum latency, as any
idle sleep/clock speed switching will cause havoc

Indeed there was one more setting I didn't turn off completely. However, after setting everything to "disabled" in the BIOS that offered me to do so and running the test again I got a max jitter of ~20k for 8 hours and currently see ~30k after 10 hours. Is there anything else I could look for?

Hi

The latency test is a cumulative one, so a single high spike of X ms will push the result to that level for the duration of the test.

A test with 6 x glxgears, moving some files and moving windows etc to cause redrawing is generally enough.
Trying to run flash videos, which you would never do on a running controller, is probably too much for an onboard video chip, which will rely upon system CPU and RAM.

To try to isolate spikes to a particular event, see my FAQs at the head of the Computer section for details of running the realtime latency test in a terminal.

Besides BIOS settings, the other line to look at is isolation of cpu cores via isolcupus boot line parameter (also discussed in the FAQs)
The specs I looked at suggest the 1900 has a 4 core processor.

regards