[SOLVED] TSC on Atom CPU and downscaling CPU frequency

[agent_kith]

I have been trying a setup consisting of an I3 laptop as a roon server and a Jetway NF9C atom board as a renderer running roonbridge.  more detail is available here https://www.stereo.net.au/forums/topic/8.../?page=124 
Some suggestions on the thread have been to use tsc as the timer and this is possible on the I3 but not on the Atom board


so@so-desktop:~$ dmesg | grep -i tsc
[    0.000000] tsc: Fast TSC calibration using PIT
[    0.000000] tsc: Detected 1862.228 MHz processor
[    0.355395] TSC synchronization [CPU#0 -> CPU#1]:
[    0.355397] Measured 64869 cycles TSC warp between CPUs, turning off TSC clock.
[    0.355403] tsc: Marking TSC unstable due to check_tsc_sync_source failed
[    0.654091] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x35af94fd872, max_idle_ns: 881590752918 ns

I tried another atom board with similar result. Is this an atom issue or SO?

Another suggestion was to underclock the CPU, this didnt seem possible within SO. Is it or will it be possibe?

Did you disable hyper-threading in your NF9C?

This message "Measured 64869 cycles TSC warp between CPUs, turning off TSC clock." means the time isn't sync'ed across the CPUs. i.e. CPU A is reporting the time as X, CPU B is reporting time at that moment is 64869 cycles after X.

My stereo is out of commision at the moment as my PSAudio P5 can't power up so can't test this out atm. It could be a linux kernel issue or a system one, can't be sure at the moment.

But for now, try the following:

1. Disable all power saving options in the BIOS
   
2. Look for HyperThreading and turn it off.
   
3. Make sure HPET is turned on in the BIOS (You can still tell Linux to use TSC even with this on).
   

If you can, generate a diagnostic file with all the options set above and send it to me to have a look.