Comment # 24 on bug 1191322 from Sinisa Bandin

(In reply to Sinisa Bandin from comment #19)
> (In reply to Ulrich Windl from comment #17)
> > (In reply to Sinisa Bandin from comment #15)
> > 
> > > Without parallel:
> > > real    0m43.247s
> > > user    0m32.279s
> > > sys     0m14.510s
> > > 
> > > With parallel:
> > > real    0m6.568s
> > > user    0m30.678s
> > > sys     0m9.899s
> > 
> > The fact that parallel execution uses less user and sys CPU made me wonder:
> > Did you flush the caches before each test?
> 
> No, this is all after running dracut a few times without "time" and doing
> some other random stuff. I just wanted to see the general effect, didn't
> mind about +/- 10%
> 
> Now that you say it, it is interesting observation... will take another try
> afternoon, flushing the caches before each run.

Update: today I ran
# echo 3 > /proc/sys/vm/drop_caches 
# time dracut --regenerate-all  --force
real    0m46.378s
user    0m33.050s
sys     0m15.357s

# time dracut --regenerate-all  --force
real    0m45.354s
user    0m33.651s
sys     0m15.396s


# echo 3 > /proc/sys/vm/drop_caches 
# time dracut --regenerate-all --regenerate-parallel --force
real    0m7.192s
user    0m30.539s
sys     0m10.914s

# time dracut --regenerate-all --regenerate-parallel --force
real    0m6.489s
user    0m30.081s
sys     0m10.178s

So cache plays no big role with Ryzen 7 and NVMe (in a laptop).