Re: CPU report in first line of "vmstat 1" is meaningless

On Tuesday, October 19, 2010 10:40:56 am Lars Engels wrote:
> On Tue, Oct 19, 2010 at 08:54:38AM -0400, John Baldwin wrote:
> > On Monday, October 18, 2010 3:30:11 pm Ed Maste wrote:
> > > On Mon, Oct 18, 2010 at 01:11:42PM -0500, Dan Nelson wrote:
> > > 
> > > > Maybe only blank it out on 32-bit machines?  It's a long, and a 64-bit
> > > > cp_time value essentially won't roll over (at 1 billion increments per
> > > > second it will roll over in 500 years; we currently increment 133 times per
> > > > second, I think).  If the value can be calculated accurately, it should be
> > > > printed.
> > > 
> > > Well, it won't roll over, but it's still different from all following
> > > lines (in that it effectively shows user/system/idle CPU usage since
> > > boot on the first line, and a snapshot over the last interval from then
> > > on).  I think it's still better to avoid printing it in that case.
> > 
> > All of the first line is that way though.  To do this "right" you'd need to
> > blank out the entire first line.
> > 
> > vm_stat and iostat on OS X have the current FreeBSD behavior (instant first
> > line that summarizes all activity since uptime), so I'd be inclined to just
> > leave the existing behavior.
> 
> I'd be very happy if all vmstat and iostat would get a command line
> switch to suppress the "summary since last reboot" line.
> This information may be useful for some cases but in other cases, like
> creating performance data for monitoring systems like Icinga / Nagios
> one has to remove the first line(s) manually.

I would be fine with that, but I wouldn't alter the format of that line by
default.

-- 
John Baldwin