Re: Increases in build system time

[Mateusz Guzik <mjguzik%gmail.com@localhost>]

On 11/14/19, Andreas Gustafsson <gson%gson.org@localhost> wrote:
>
> Hi all,
>
> Back in September, I wrote:
>> I'm trying to run a bisection to determine why builds hosted on recent
>> versions of NetBSD seem to be taking significantly more system time
>> than they used to, building the same thing.
>
> I finally have some results to report.  These are from builds of the
> NetBSD-8/amd64 release hosted on various versions of -current/amd64,
> on a HP DL360 G7 with dual Xeon L5630 CPUs (8 cores in all).  The
> amount of system time taken by each build was measured using time(1).
>
> Between a -current from September 2016 and one from October 2019, the
> system time more than doubled, from 4245 seconds to 9344 seconds.
> The time(1) output from the oldest and newest version was:
>
>     3930.86 real     15737.04 user      4245.26 sys
>     4461.47 real     16687.37 user      9344.68 sys
>

Can you get a kernel-side flamegraph?

# dtrace -x stackframes=100 -n 'profile-997 /arg0/ { @[stack()] =
count(); }' -o out.kern_stacks -c "your_build_command" or so.

cat out.kern_stacks | perl stackcollapse.pl | perl flamegraph.pl > fg.svg

See https://github.com/brendangregg/FlameGraph.git

I know it used to work fine, but tried it few months back in a vm and
profile- probes were not there. I don't know if it was a local wart.

-- 
Mateusz Guzik <mjguzik gmail.com>