Messages in this thread | | | Subject | Re: [PATCH 7/7] docs: proc.rst: stat: Note the interrupt counter wrap-around | From | Randy Dunlap <> | Date | Fri, 10 Sep 2021 20:59:26 -0700 |
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On 9/10/21 8:48 PM, Alexei Lozovsky wrote: > Let's make wrap-around documented behavior so that userspace has no > excuses for not handling it properly if they want accurate values. > > Both "intr" and "softirq" counters (as well as many others, actually) > can and will wrap-around, given enough time since boot. > > Signed-off-by: Alexei Lozovsky <me@ilammy.net> > --- > Documentation/filesystems/proc.rst | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst > index 042c418f4090..06a0e3aa2e0e 100644 > --- a/Documentation/filesystems/proc.rst > +++ b/Documentation/filesystems/proc.rst > @@ -1513,6 +1513,13 @@ interrupts serviced including unnumbered architecture specific interrupts; > each subsequent column is the total for that particular numbered interrupt. > Unnumbered interrupts are not shown, only summed into the total. > > +.. note:: > + > + Interrupt counters on most platforms are 32-bit, including the total count. > + Depending on the system load, ths values will sooner or later wrap around.
these
> + If you want accurate accouting of the rate and *real* number of interrupts
accounting
> + serviced, you should monitor the value closely and handle wrap-arounds. > + > The "ctxt" line gives the total number of context switches across all CPUs. > > The "btime" line gives the time at which the system booted, in seconds since >
thanks. -- ~Randy
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