[tex4ht] what is the fastest way to convert large document to HTML?

[Nasser M. Abbasi]

>> The speed is AMAZING !!  minutes now instead of hours. It might be due to
>> the use of
>>
>>    make -j6 -f try-images.mk
>>

I have a question:  How does make4ht decide on using
make -j6 or other number for the parallel part?

I am asking, becuase as I am testing it, I see it used make -j1 in
here

----(this is on Linux VBox) -----------------
index-d6a6cb6c8ee1ee4f8e0d99c8affcaf33.svg
index-41454bd3eeafc1f1acc1d3fa55931416.svg
make -j1 -f index-images.mk
make[1]: Entering directory '/mnt/public_html/my_notes/solving_ODE/current_version'
make[1]: Warning: File 'index-images.mk' has modification time 1.5 s in the future
dvisvgm -v4 -n --exact -c 1.15,1.15 -p 2-15,17,19-24,26-33,35-38,40-47,49-57,59,61-67,69-74 index.idv 2> index-1.dlog
.....
------------------------

The above is running now a Linux VBox (I lost my Ubuntu linux subsystem
in windows, so I am resinstalling it again as we speak). In the example
with j6, I using that.

How is the numebr following "j" decided on?  On Linux Manjaro VBox, make is GNU

>make -v
GNU Make 4.2.1
Built for x86_64-unknown-linux-gnu

And on Ubuntu under windows 10, it is also gnu make:
>make -v
GNU Make 4.1
Built for x86_64-pc-linux-gnu

Or may be becuase on VBox, only one core can be used (as far as I know)
and make4ht checked for this, and that is why it used j1 while on
windows linux subsystem more cores can be used and it used all available there?

My PC happens to have 6 cores actually.

In this case, I will use windows 10 linux subsystem only for builds,
since then it can do j6. I justed wanted to check with the experts
if this is what happened.

thanks
--Nasser