In PC port, there is no configCPU_CLOCK_HZ set, nor any of the RTOS code there uses it. What is frequency of timer with this port? Would setting this variable have any influence to the frequency of timer? If not, what is default value for it?

I figured it out. An all PCs, the frequency generator that runs the counter circuit works at the same frequency, so the configCPU_CLOCK_HZ is not needed.