Error running on ARM based linux

[schveiguy]

Error running on ARM based linux

[schveiguy]

It seems that the array is empty that is being iterated over, and for some reason on Linux/ARM on this VM, this causes the error to occur. Still investigating, I'm not 100% sure it's OK for the list to be empty, but maybe it's ok and indeed an issue on phobos. Will debug further.

[schveiguy]

I figured it out. Three conditions are happening:

1. I have allocated only one CPU to the VM. This is reasonable for me, since I don't care about parallel execution here (this is a vibe-d app), and I don't want to consume resources from my main system.
2. std.parallelism assigns a default thread pool size as numCPUs - 1. i.e. 0 threads.
3. This array that reggae is looping over is of length 0. So it decides to use 0 as the work unit size, and hence the error.

I have to examine why 0 is a problem here. I think the reason for the numCPUs - 1 is because you obviously have the CPU you are using to call the function! But then why does it fail if it can only use that one?

For now, I can up the CPUs to 2 on my VM, and file a bug in Phobos.

[schveiguy]

Bug report: https://issues.dlang.org/show_bug.cgi?id=22745

[atilaneves]

It's from std.parallelism, so probably a Phobos bug on that platform.