[OE-core] Some notes on speeding up do_package_write_rpm

[Khem Raj]

On Wed, Feb 8, 2012 at 6:54 AM, Richard Purdie
<richard.purdie at linuxfoundation.org> wrote:
> real    7m15.207s
> user    2m31.320s
> sys     0m27.720s
>
> and after, with the python script:
>
> real    5m23.727s
> user    3m25.540s
> sys     1m4.530s
>
> So in real terms its much faster but it claims to be using more user and
> sys resources. So it looks to be a performance speedup (and everything
> I've done would agree with that) but those user/sys numbers don't make
> sense.
>
> I find the first set of numbers odd anyway as how can something spending
> 2.5 minutes in user and 0.5 minutes in sys making a total of 3 minutes,
> take 7.25 minutes to run on a multicore system that is otherwise idle. I
> suspect somewhere, the accounting in the kernel is screwing up maybe in
> the handling of the many short lived processes we were triggering.

yeah could be its so small that it gets rounded off.

The
> real numbers correspond with my stopwatch so I'm happy to proceed with
> changes in this direction but if anyone does understand why those
> numbers would differ like that, I'd be interested to know about it.

I think it could be that there is more parallel threads now. since user+sys
is across all cpus so you see more user+sys but overall real time
is improved so its good.