Updated, PTAL

Is this really correct? I think we do use CPU threads not cores directly here, for example:

Intel® Core™ i7-4790 Processor has only 4 cores but 8 threads:
http://ark.intel.com/products/80806/Intel-Core-i7-4790-Processor-8M-Cache-up-to-4_00-GHz

@PeterDaveHello then on that processor, the number of make jobs should be 3.

It'll be 7, as you'll see 8 cores there, and it'll be faster than 3.

Perhaps the terms "core" and "thread" are used a bit loosely?

My intention is that there should always be at least one execution context, that is not from nvm install -s, that can run simultaneously - for example, to run kill.

I don't think the terms "core" and "thread" are used a bit loosely, I'll call it threads but not cores, they are different, at least, call them CPUs, as other common programs, I didn't see any common case which really needs to take the physical cores rather than the threads on the cores, maybe I should just send a PR to modify it again to call it NVM_CPUS.

If you really think we should use 3 cores not 7 threads in the hyper-threading cases, you should use the cpu cores info in /proc/cpuinfo or something like lscpu but not directly count the process in it.

$ lscpu 
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    2
Core(s) per socket:    4
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 30
Stepping:              5
CPU MHz:               2794.000
BogoMIPS:              5922.27
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              8192K
NUMA node0 CPU(s):     0-7

Do we really need to use the term "CORE" here? Maybe should open an issue for the discussion?

Sure, an issue is great.

@PeterDaveHello I'd say that Cores is still more appropriate than threads. I agree that if you have an Intel core with hyperthreading then you can run two threads at a time on each core, but most OSs spin up a bunch of threads and context switch between them, and I'd say that's the more common meaning of threads. From the OS, a processor with 4 physical cores and hyperthreading (or a single Power8 processor) would look like 8 "virtual cores" to the OS.

My activity monitor atm:

Task manager:

Happy to discuss further on an issue!

@gibfahn just reply to your activity monitor here, the threads term here is not about how many threads we have on CPU but how many threads the software created on the OS.

@PeterDaveHello that's what "threads" most commonly means to programmers - software threads created by the OS.