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Thank you. This makes alot of sence.
This also explains why using CPUBurn the system CPU usage indicates a
percentage, as there is now wait time for that process.
Mike
----- Original Message -----
From: "Julian Anastasov" <ja@xxxxxx>
To: "Joseph Mack" <mack.joseph@xxxxxxx>
Cc: <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Sent: Monday, September 10, 2001 3:54 PM
Subject: Re: CPU Usage
>
> Hello,
>
> On Mon, 10 Sep 2001, Joseph Mack wrote:
>
> > > Michael McConnell wrote:
> > >
> > > Top doesn't display CPU usage of IPChains or IPVSADM
> > > VMStat doesn't display CPU usage of IPChains or IPVSADM
> >
> > ipchains and ipvsadm are user tools that configure the kernel.
> > After you've run them, they go away and the kernel does it's new
> > thing (which you'll see in "system").
> >
> > Unfortunately for some reason
> > that no-one has explained to me "top/system" doesn't see everything.
> > I can have a VS-DR director which is running 50Mbps on a 100Mpbs link
> > and the load average doesn't get above 0.03 and system to be
> > negligable. I would expect it to be higher.
>
> Yes, the column is named "%CPU", i.e. the CPU spend for
> one process related to all processes. As for the load average, it is
> based on the length (number of processes except the current one) of
> the queue with all processes in running state. As we know, LVS does
> not interract with any processes except the ipvsadm. So, the normal
> mode is the LVS box just to forward packets without spending any CPU
> cycles for processes. This is the reason we to see load average 0.00
>
> OTOH, vmstat reads /proc/stat and there are the counters
> for all CPU times. Considering the current value for jiffies (the
> kernel tick counter) the user apps can see the system, the user and
> the idle CPU time. LVS is somewhere in the system time. For more
> accurate measurement for the CPU cycles in the kernel there are some
> kernel patches/tools that are exactly for this job - to see what time
> takes the CPU in some kernel functions.
>
> > Joe
>
> Regards
>
> --
> Julian Anastasov <ja@xxxxxx>
>
>
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