Re: [Qemu-devel] [PATCH 0/2] Reduce lock contention on TCG hot-path

[Paolo Bonzini]

On 02/07/2016 09:08, Alex Bennée wrote:
> Hmm I was doing from memory but it should be the mean of the sum of the
> squares of the deviation:
> 
>         # calculate deviation
>         deviation = 0
>         for r in res:
>             deviation += (r.time - avg_time)**2
> 
>         deviation = deviation / count

This is the population variance.  "Standard deviation" and "variance"
usually refer to the sample standard deviation and sample variance,
where you divide by count-1.

For the population stdev and sample stdev you have to take the square root.

LibreOffice agrees with Emilio, giving a sample stdev of 0.2742 and a
population stdev of 0.2453

Paolo