Earlier quoted context omitted.
As long as we’re being pedantic, Mandelbrot is a name.
Names are words.
No, names can consist of more than one word. "New York City" for example is three words making up one name.
What should the CPU usage be of a fully-loaded CPU that has been throttled?
131–140 of 181 posts
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#132Earlier quoted context omitted.
> my cpu very quickly hit 99c also at 100% That should never happen and it's ridiculous that we just let manufacturers get way with it.
Why? 100c is typically the max nominal safe operating temp for CPUs. It would be a waste of resources to add additional cooling to computers not intended to run these type of workloads. Prime95 is basically a synthetic workload so it makes little sense to optimize for it.
How did you determine that 100c is safe?
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#133Earlier quoted context omitted.
> my cpu very quickly hit 99c also at 100% That should never happen and it's ridiculous that we just let manufacturers get way with it.
Why? 100c is typically the max nominal safe operating temp for CPUs. It would be a waste of resources to add additional cooling to computers not intended to run these type of workloads. Prime95 is basically a synthetic workload so it makes little sense to optimize for it.
Yeah, the thing is it doesn't only happen in prime95. Nowadays it's any prolonged use where the CPU is fully used, like video editing or gaming. Give an inch and they'll take a mile, as the saying goes.
Temperature junction throttling is a last resort. No laptop should rely on it in normal operation. Of course, both HP/Dell/Lenovo/etc and Intel benefit from increased sales so they don't care.
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#134Earlier quoted context omitted.
Why? 100c is typically the max nominal safe operating temp for CPUs. It would be a waste of resources to add additional cooling to computers not intended to run these type of workloads. Prime95 is basically a synthetic workload so it makes little sense to optimize for it.
How did you determine that 100c is safe?
The manufacturer did and put it in the datasheet of the CPU
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#135If you say “there are two perspectives on reporting this fact”, what you really mean to say is “there are two things to report here”
Exactly, why not report both? I for one would want to know both.
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#136Earlier quoted context omitted.
Why? 100c is typically the max nominal safe operating temp for CPUs. It would be a waste of resources to add additional cooling to computers not intended to run these type of workloads. Prime95 is basically a synthetic workload so it makes little sense to optimize for it.
Yeah, the thing is it doesn't only happen in prime95. Nowadays it's any prolonged use where the CPU is fully used, like video editing or gaming. Give an inch and they'll take a mile, as the saying goes. Temperature junction throttling is a last resort. No laptop should rely on it in normal operation. Of course, both HP/Dell/Lenovo/etc and Intel benefit from increased sales so they don't care.
Counterpoint - during typical (consumer) usage hardware spends most of the time idle. Hardware capable of sustaining the maximum workload indefinitely is likely to have a lower maximum in practice. Unsustainable bursts are likely to provide higher overall performance for typical workloads, so it makes sense to optimize the hardware design for those.
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#137Power saving and "throttling" (usually it's un-turboing) are different cases that shouldn't be conflated; in one case the processor could run faster but in the other it can't. Ultimately we may want different metrics depending on what they're going to be used for. If you calculate relative to base frequency you will get utilization over 100% which is going to confuse some people. Linux has done some work in this area…
MacOS has a weird solution to throttling. They put a fake process in the process list which looks like it consuming x% of the resources but really it is just blocking some usage to allow the CPU to cool.
I wished they would have a separate, properly named process for it. My old MB Pro (late 2015) was throtteling a lot and it took me very long to recognize, as it was just "kernel task" gobbling up cpu. Getting the machine cleaned out at a service center did help a lot, I wonder, whether redoing the thermal paste on the cpu would have improved it further, but I ended up replacing it with a current model.
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#138I don’t think the article’s solution is a good one. The CPU metric is on its own really hard to understand and complex. I’d rather have the OS to understand and report when the CPU is throttled and do the reporting accordingly. So the metrics are easier to interpret.
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#139Earlier quoted context omitted.
“Military power “ seems to fit perfectly… > The etiology of military power is from War Emergency Power (WEP) which in the WWII era was a higher than normal rating power (i.e. >100% rated power) setting on an aircraft engine. Such power settings were approved for short durations (typically 5 minutes or less) such as takeoff and battle maneuvers. > The term was quickly shortened to military power.
"Overdrive"
Turbo. I miss the old turbo button, even when it didn't actually do much of anything.
Re: What should the CPU usage be of a fully-loaded CPU that has been throttled?
#140I think there are two different use cases:
- measurement at thread level (top and the like) should report instructions retired per unit of time, not %CPU. We want to know how much work is being done. The explanation on why so much/so little requires more information (scheduler? cache misses? cpu throttling?)
- measurement at the CPU level (mpstat, etc) should report both %CPU (as "time active" vs "wall clock time") and active clock cycles per unit of time (dividing by clock stretching factor if used, and perhaps scaled to absolute max frequency and/or %CPU if one wants a percentage).
%CPU tells us whether we are making full use of the available time, and perhaps suggests to schedule threads differently if appropriate
Clock cycles tell us how much one CPU is affected by throttling (manual, automatic, due to C-state exits, etc), and this is an orthogonal indication on whether there is something at the system level that is making the CPU underutilized