[SOLVED] TSC on Atom CPU and downscaling CPU frequency

[agent_kith]

Hi I have been using Roonbridge and not sure this gets isolated to cpu1.

Not entirely sure as I havn't tested RoonBridge myself. One quick way to test is to go to the Snakeoil menu after RoonBridge has started and see if it's isolated. If it's not there, then it's likely the command to isolation the cores is executed before RoonBridge has started.

I think this happens with MediaCenter, and it's very likely Roon is affected as well (As RoonBridge uses C#, which is like JAVA and have more overheads, hence loading up will be slow).
 

Finally had a good listen to the 300hz kernel with both tsc and hpet clock and found I preferred the standard kernel in the end. I also compared it with an SOTM SMS200 ultra and really couldnt pick much between them so congrats on a great bit of software.

This is because I spent more time tweaking the standard kernel. If I start with a 300 Hz (or some other frequency, say 1000 Hz), then slowly tweak the other stuffs, who knows, it may beat the standard kernel then? Time is the enemy here as there're quite a few things to experiment with. And evaluation can be difficult. e.g. one may prefer the standard kernel, but this may be because it's less revealing than the 300 Hz one. Sometimes it's really hard to make the call. Sometimes to make the difference easier to perceive, I have to dial up the volume a lot higher than I'm comfortable with. And the longer one spend time auditioning the kernels, the more they all begin to sound the same.

It is amazing (and mysterious) why software can do this.
 

I also found that reducing vm stat polling "sysctl -w vm.stat_interval=3600" and to a lesser extent setting the hpet timer frequency " echo "8192" | sudo tee --append /proc/sys/dev/hpet/max-user-freq" helped. These were not my ideas but from @rmpfyf on SNA. 

Cool. I'm thinking of adding a feature that allows folks to enter custom bootup commands. When that is ready you can put these commands there (I'd probably make these the default).

 

I also tried to lower cpu frequency but the kernel did not allow it, is this something you have tried previously? 

CPU Frequency cannot be adjusted with the two kernels you have tried because that part of the code is disabled. Power saving features usually add latencies. You can install the CPUFfreq kernel to add this support if you like (e.g. useful when running on a notebook that's battery powered)...

Some motherboards allow you to adjust the CPU speed by changing the multiplier and/or the bus speed. I remember adjusting the CPU frequency to make it divisible by 44100 before back when I was using a full ATX PC before. FWIW now using a JS-2 with big hashimoto tranny and choke I don't think that's necessary any more. So in a way there may be a relationship between CPU speed and input power. (Disclaimer: I'm only guessing here!).