Re: Build time measurements

[Andrew Doran <ad%netbsd.org@localhost>]

Hi Andreas,

On Fri, Mar 27, 2020 at 10:39:44AM +0200, Andreas Gustafsson wrote:
> On Wednesday, I said:
> > I will rerun the 24-core tests with these disabled for comparison.
> 
> Done.  To recap, with a stock GENERIC kernel, the numbers were:
> 
> 2016.09.06.06.27.17    3321.55 real      9853.49 user      5156.92 sys
> 2019.10.18.17.16.50    3767.63 real     10376.15 user     16100.99 sys
> 2020.03.17.22.03.41    2910.76 real      9696.10 user     18367.58 sys
> 2020.03.22.19.56.07    2711.14 real      9729.10 user     12068.90 sys
> 
> After disabling DIAGNOSTIC and acpicpu, they are:
> 
> 2016.09.06.06.27.17    3319.87 real      9767.39 user      4184.24 sys
> 2019.10.18.17.16.50    3525.65 real     10309.00 user     11618.57 sys
> 2020.03.17.22.03.41    2419.52 real      9577.58 user      9602.81 sys
> 2020.03.22.19.56.07    2363.06 real      9482.36 user      7614.66 sys

Thanks for repeating the tests.  For the sys time to still be that high in
relation to user, there's some other limiting factor.  Does that machine
have tmpfs /tmp?  Is NUMA enabled in the BIOS?  Different node number for
CPUs in recent kernels in dmesg is a good clue.  Is it a really old source
tree?  I would be interested to see lockstat output from a kernel build at
some point, if you're so inclined.

Cheers,
Andrew