Don't use `nproc --all` for getting cpu number. For example below,

Don't use `nproc --all` for getting cpu number. For example below,
sparc64 is reporting 128 as a total, but only 32 is online. So use only
online cpus for tests parallel runs.

$ nproc
32

$ nproc --all
128

$ lscpu
Architecture:        sparc64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Big Endian
CPU(s):              32
On-line CPU(s) list: 0-31
Thread(s) per core:  8
Core(s) per socket:  4
Socket(s):           1
Model name:          UltraSparc T5 (Niagara5)
Flags:               sun4v

Signed-off-by: Anatoly Pugachev <matorola@gmail.com>