Invalid memory stats from vmstat and sysctl vm.vmtotal?

[Damien Fleuriot]

On 12/1/11 11:44 AM, Steven Hartland wrote:
> ----- Original Message ----- From: "Jason Hellenthal" <jhell at DataIX.net>
> 
>> This goes along with the thoughts I had about 4 months ago tending to
>> some
>> zfs statistics as well top showing greater than 100% actual CPU usage.
>> This
>> is a big pet peave of mine. Its like saying you ate 134% of a bannanna
>> when
>> in all reallity it is impossible. You can never have more than 100%
>> usage of
>> anything and when seen is a clear notice that some math is considerably
>> incorrect leading to other such miscalculations to be performed.
>> Things like
>> the above already have checks in place that ensure no boundries are being
>> crossed/overflowed or underrun but it surely makes processing results
>> building
>> future products a bitch. One instance is the calculation of threads
>> for example
>> firefox can be seen using upto or more 338% of the CPU. Thats
>> impossible its
>> like saying anyones CPU grew by 400%.
> 
> I could understand a bit of overflow as stats are snapshots which may not
> be instuntanious, but 31GB instead of under 8GB is hardly a rounding
> issue /
> overflow.
> 
> With respect to top showing greater than 100% by how much are you talking?
> Do your realise that each core = 100%? So if you have a quad core your
> system
> total will be 400% not 100%?
> 

That's his point, you cannot use 400% of a system as a whole, his point
is that top should report 100% where each core accounts for 25%