BTW, I must not understand this whole thermald/powerclamp/kidle-inject because it seems like a dumb thing to do.
If you want to keep the CPU cool and prevent the fan kicking in, then limit the clock speed. Writing a process that instead kicks in and forces idle time seems overly complex and inefficient.
I must be missing something because it seems whoever wrote this missed the forest for the trees.
1. Removing this stuff as described in the 1st post restores the correct behavior. Under low CPU usage the fan is off and you get great battery life. As CPU usage ramps up, the fan turns on to cool the CPU and battery life shortens while you get full performance.
2. Having this stuff installed prevents the XPS-13 from getting full performance - even when plugged in!
It remains a mystery to me why anyone built this instead of simply throttling back the CPU speed. But at least it can be removed.
I'll try to explain the mystery. Powerclamp is another tool to limit power consumption. Reducing CPU speed is another way to do this, but one processor running fast while another is idle might use more power than having two running at less than maximum speed depending on the details. Forcing a processor to be idle part of the time can allow finer control over how long a processor is idle as compared to reducing speed (and equating reduced speed to idle time). Powerclamp just forces idle time; it doesn't have any logic to decide how idle the processor should be. It is not used to the exclusion of reducing CPU speed.
thermald is what decides when idle time should be forced and how much. It can make that decision to impose a power limit or a temperature limit.
Given your symptoms, I'd say something is misconfigured. I didn't experience the problems, but it does seem as though powerclamp isn't being used on my system. I might just not be looking when it is used, though.
Before moving to Mint i also experienced problems with powerclamp/thermald. However it was happening only when running windows on a vm. Disabling both solved the problem.
MRC01
80 Posts
0
June 1st, 2015 11:00
BTW, I must not understand this whole thermald/powerclamp/kidle-inject because it seems like a dumb thing to do.
If you want to keep the CPU cool and prevent the fan kicking in, then limit the clock speed. Writing a process that instead kicks in and forces idle time seems overly complex and inefficient.
I must be missing something because it seems whoever wrote this missed the forest for the trees.
MRC01
80 Posts
0
June 1st, 2015 13:00
I tested both ways and confirmed:
1. Removing this stuff as described in the 1st post restores the correct behavior. Under low CPU usage the fan is off and you get great battery life. As CPU usage ramps up, the fan turns on to cool the CPU and battery life shortens while you get full performance.
2. Having this stuff installed prevents the XPS-13 from getting full performance - even when plugged in!
It remains a mystery to me why anyone built this instead of simply throttling back the CPU speed. But at least it can be removed.
jjackowski
7 Posts
0
June 21st, 2015 19:00
I'll try to explain the mystery. Powerclamp is another tool to limit power consumption. Reducing CPU speed is another way to do this, but one processor running fast while another is idle might use more power than having two running at less than maximum speed depending on the details. Forcing a processor to be idle part of the time can allow finer control over how long a processor is idle as compared to reducing speed (and equating reduced speed to idle time). Powerclamp just forces idle time; it doesn't have any logic to decide how idle the processor should be. It is not used to the exclusion of reducing CPU speed.
thermald is what decides when idle time should be forced and how much. It can make that decision to impose a power limit or a temperature limit.
Given your symptoms, I'd say something is misconfigured. I didn't experience the problems, but it does seem as though powerclamp isn't being used on my system. I might just not be looking when it is used, though.
andrea.B
5 Posts
0
June 22nd, 2015 03:00
Just to share my experience
Before moving to Mint i also experienced problems with powerclamp/thermald. However it was happening only when running windows on a vm. Disabling both solved the problem.