On Fri, Aug 11, 2023 at 11:25 PM Martin Husemann <mar...@duskware.de> wrote:
>
> On Fri, Aug 11, 2023 at 07:04:01PM -0700, Kevin Bowling wrote:
> > A real example is doing a -j 8 kernel build. Up in the top of top(1),
> > I see global CPU usage in the high 90%. Down in the process list, I
> > see a few processes in the 1-10% range that do not add up to 800%. I
> > see some of the cc1 processes with 0% WCPU%/CPU%.
>
> I am not sure I see what you mean, for me typically there are a few gcc
> processes that take all the cpu, or later (close to the end) a few
> xz or gzip processes. At a few spots ld wins and hogs at least one cpu
> completely.
>
> At least it looks not completely off, the top area displays statistics for
> aggregated intervals, while many processes (besides the ones mentioned)
> are very short lived - so the display is mostly what I'd expect it to be.
>
> If you do "top -b" (so the list is not truncated) and save it to a file,
> do you get a snapshot that is still unreasonable from your POV? Can you
> share a concrete example?
Here's a sample, this one is a bit better since the cc1plus processes
stick around for a bit longer but it still shows the WCPU% not adding
up near the global CPU stats. I can annotate it as an image if it is
still not clear.
load averages: 6.15, 3.21, 1.67; up 0+04:56:56
12:37:26
142 threads: 2 runnable, 123 sleeping, 10 zombie, 7 on CPU
CPU0 states: 92.6% user, 0.0% nice, 7.4% system, 0.0% interrupt, 0.0% idle
CPU1 states: 91.6% user, 0.0% nice, 8.2% system, 0.0% interrupt, 0.2% idle
CPU2 states: 91.6% user, 0.0% nice, 8.4% system, 0.0% interrupt, 0.0% idle
CPU3 states: 89.4% user, 0.0% nice, 10.0% system, 0.0% interrupt, 0.6% idle
CPU4 states: 57.9% user, 0.0% nice, 10.2% system, 0.0% interrupt, 31.9% idle
CPU5 states: 99.8% user, 0.0% nice, 0.2% system, 0.0% interrupt, 0.0% idle
CPU6 states: 96.2% user, 0.0% nice, 3.4% system, 0.0% interrupt, 0.4% idle
CPU7 states: 97.0% user, 0.0% nice, 3.0% system, 0.0% interrupt, 0.0% idle
Memory: 7213M Act, 5392K Inact, 110M Wired, 105M Exec, 5933M File, 7165M Free
Swap: 16G Total, 16G Free / Pools: 1017M Used
PID LID USERNAME PRI STATE TIME WCPU CPU NAME COMMAND
1598 1598 kev009 25 CPU/5 0:26 98.03% 72.66% - cc1plus
6906 6906 kev009 25 CPU/7 0:26 96.51% 71.53% - cc1plus
29633 29633 kev009 25 CPU/2 0:01 64.58% 6.15% - cc1plus
6016 6016 kev009 25 CPU/6 0:01 75.00% 3.66% - cc1plus
5636 5636 kev009 25 CPU/1 0:01 50.00% 2.44% - cc1plus
2855 2855 kev009 85 poll/1 1:14 0.59% 0.59% - xfce4-terminal
1867 1867 kev009 85 poll/3 2:00 0.00% 0.00% - X
2041 2041 kev009 85 poll/0 0:19 0.00% 0.00% - xfwm4
1867 1629 kev009 85 poll/3 0:14 0.00% 0.00% - X
2016 2016 kev009 85 poll/7 0:07 0.00% 0.00% - xfce4-panel
2099 2099 kev009 85 poll/1 0:03 0.00% 0.00% - xfdesktop
2239 2239 kev009 85 select/0 0:02 0.00% 0.00% - xscreensaver
598 598 root 85 poll/2 0:01 0.00% 0.00% - dhcpcd
599 599 _dhcpcd 85 poll/3 0:01 0.00% 0.00% - dhcpcd
2016 2089 kev009 85 poll/0 0:01 0.00% 0.00% gmain xfce4-panel
774 774 kev009 85 poll/0 0:01 0.00% 0.00% - gvfsd-trash
18154 18154 kev009 43 CPU/3 0:00 0.00% 0.00% - top
3737 3737 kev009 25 CPU/0 0:00 0.00% 0.00% - cc1plus
15778 15778 kev009 25 RUN/3 0:00 0.00% 0.00% - cc1plus
9044 9044 kev009 25 RUN/3 0:00 0.00% 0.00% - cc1plus
3365 3365 kev009 86 wait/0 0:00 0.00% 0.00% - su
1 1 root 85 wait/3 0:00 0.00% 0.00% - init
23460 23460 kev009 85 poll/1 0:00 0.00% 0.00% - nbmake
1402 1402 kev009 85 poll/2 0:00 0.00% 0.00% - nbmake
19515 19515 kev009 85 ttyraw/0 0:00 0.00% 0.00% - sh
545 545 kev009 85 poll/6 0:00 0.00% 0.00% - thunar
2016 2087 kev009 85 poll/1 0:00 0.00% 0.00% gdbus xfce4-panel
2044 2205 kev009 85 poll/2 0:00 0.00% 0.00% gdbus xfsettingsd
2044 2019 kev009 85 poll/2 0:00 0.00% 0.00% gmain xfsettingsd
2044 2044 kev009 85 poll/2 0:00 0.00% 0.00% - xfsettingsd
2041 2267 kev009 85 poll/7 0:00 0.00% 0.00% gdbus xfwm4
2041 1886 kev009 85 poll/5 0:00 0.00% 0.00% gmain xfwm4
2036 2036 kev009 85 poll/3 0:00 0.00% 0.00% - ssh-agent
1617 2037 kev009 85 poll/4 0:00 0.00% 0.00% gdbus
at-spi2-registry
1617 2021 kev009 85 poll/6 0:00 0.00% 0.00% gmain
at-spi2-registry
1617 1617 kev009 85 poll/1 0:00 0.00% 0.00% -
at-spi2-registry
> For FreeBSD showing the values more like you expect I'd blame that on clang/
> llvm being slow, but I'll be shot for this remark :-)
There's probably something to that.
> But still specualting without data: one thing that could make a serious
> difference is the device you are running your build.sh on having a
> suboptimal driver spending a lot of cpu in the kernel for the IO the
> build produces.
> Martin
