On 25/11/2014 16:19, Viresh Kumar wrote: > On 25 November 2014 at 18:32, Mason <mpeg.blue@xxxxxxx> wrote: > >> As far as I can tell, on my SoC, the timer runs at 27 MHz. >> But I have no idea how often it fires an interrupt. > > 27 MHz is the freq it runs at, but we get interrupt based on the value > programmed in the timer counter. > > Look for CONFIG_HZ in your .config, that will tell you number of ticks > you are getting per second. > > But cpufreq works in another level and so it doesn't depend on both > these. If I remember correctly (please correct me if I am mistaken), the kernel keeps a list of timers, ordered by deadline, and dynamically configures the system timer to fire at the next deadline. > Look for: /sys/devices/system/cpu/cpufreq/ondemand/sampling_rate > this is the rate at which cpufreq core checks if cpu's freq require revisiting. I think setting the sampling rate to 50 ms should make the system reactive enough to load swings? >> This 'struct clk' is an elusive beast. >> Where is it defined? I only run into forward declarations. > > Its architecture specific. What's the architecture you are working on? > You may implement your own routine instead of cpufreq_generic_get(). The SoC is made by Sigma Designs. It is based on the ARM Cortex-A9. > Yes. Documentation/clk.txt. Oh boy! platform, device tree, cpu-freq, cpuidle, clk, ... so much to learn, so few hours in a day. > Yeah. You should be able to get some call from your architecture. OK, I have to fix that function along with the cpufreq update. Regards. -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
