Modal stacks cpu usage

Bob Sneidar bobsneidar at
Thu Oct 1 13:20:19 EDT 2020

I’ll weigh in here. I have noticed at times my Mac becoming slow and extremely laggy to input. Quitting all my apps, including LC seems to resolve it, although I never dug in any deeper. (Honestly I thought it was a Chrome or web page issue and I am used to those.) Next time I see the issue I will dig further.

Bob S

On Oct 1, 2020, at 9:28 AM, Richard Gaskin via use-livecode <use-livecode at<mailto:use-livecode at>> wrote:

Neville Smythe wrote:

> Typically LC cpu usage shows about 34%  (presumably of 1 core).  When
> a modal stack is opened it immediately ramps up to 99% ; the fan kicks
> in, and if left for a while the OS boosts the kernel_task daemon which
> I have been told is a protection device to prevent overheating. This
> has the effect of very markedly slowing down all apps as they get less
> cpu time.
> If the stack is opened in non-modal mode, cpu usage stays around 34% .
> I don’t understand why a modal stack should be a cpu hog, indeed it
> seems like a bug to me.

Confirmed here on macOS 10.14.5.  The CPU load is indeed quite dramatic with modal dialogs.

I also checked on Linux (Ubuntu 18.04), and LC does not exhibit the problem there.

Have you opened a bug report on this?

Richard Gaskin
Fourth World Systems
Software Design and Development for the Desktop, Mobile, and the Web

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