image: let mksquashfs4 use all processors
Drop the -processors argument from the mksquashfs4 call, so it will use
all available processors. This dramatically reduces the time to create
squashfs filesystems.
The times below are observed when building an image for my main router,
the WatchGuard Firebox M300 (qoriq target):
Before:
real 4m45,973s
After:
real 0m23,497s
With this commit `mksquashfs` may use more cores than defined via `-j`.
This is the same behaviour as for archive creation of ImageBuilder, SDK
or toolchain. There is no trivial way to limit `mksquashfs` CPU core
usage to the amount of "free" make jobs since two running `mksquashfs`
instances would each run with the total allowed number (-j) of threads.
Signed-off-by: Stijn Tintel <[email protected]>
[extended reasoning in commit message]
Signed-off-by: Paul Spooren <[email protected]>
Stijn Tintel