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Comment by ianbertolacci | Hacker News Reader

We were also wondering about existing temperature conditions. For example, I might be running some super benchmark that pegs the core temperature high. What happens when Siri turns on? If it still shuts down the fan thats bad. I could potentially keep prompting Siri (to turn off the fan) and drive the temperature a bit higher.

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I don't have an app for monitoring cpu temps right now, and don't know if there is a CLI way to do it.

I was able to keep the fan off for probably a minute before I stopped. I am interested to find out if intel's cpu throttling kicked in.

edit: installed Intel Power Gadget.

with 4 cores pegged (4 actual cores), the CPU was turbo-boosted (3.0GHz on my laptop). As I prevented the fans from running via Siri, the cpu throttled back to normal rated speed. Temperature varied by a few degrees C hovering around 99C. I did this for approximately a minute or so.

It didn't go below the rated speed (2.5GHz on my laptop).

edit2: I did it again with 4 cores pegged and 4 HT cores pegged. It didn't throttle below 2.5, but I did see that the "yes" processes were throttled back. when I glanced before stopping, they were all at 80% instead of 95+%

There's no default utility for this. There's some sysctl values for the CPU and the GPU but they don't actually give you a temperature.

There's an API for this in IOKit. Easiest way I've found to get at it on the CLI is:

    gem install istats
    istats cpu temp | awk '{gsub(/[^0-9\.]/,"",$3);print $3}'

I installed Intel Power Gadget. It's pretty nice actually, no options to configure but it's pretty useful information.

Just FYI, I had to do the following:

    $ gem install istats
    ERROR:  Could not find a valid gem 'istats' (>= 0) in any repository
    ERROR:  Possible alternatives: iStats
    $ gem install iStats
    Fetching: sparkr-0.4.1.gem (100%)
    ERROR:  While executing gem ... (Gem::FilePermissionError)
        You don't have write permissions for the /Library/Ruby/Gems/2.0.0 directory.
    $ sudo gem install iStats
    Fetching: sparkr-0.4.1.gem (100%)
    Successfully installed sparkr-0.4.1
    [...]
    This could take a while...

Then, I discovered it uses sparklines for output:

    $ istats cpu
    CPU temp: 60.625°C

Which is pretty cool.

EDIT: the sparkline doesn't show here, but it's a little bar-chart histogram

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