Re: Calculate average latencies on the fly

[John Kacur <jkacur@redhat.com>]

On Sat, 19 Nov 2016, Piotr Gregor wrote:

> Hi John, Clark,
> 
> Recently I observed jitter of > 100 000 during tests of virtualized system.
> In that case 30 years would change into 0.3 year which is not as much.
> The jitter depends on the hardware/software you test, what if someone
> deliberately wishes to measure jitter of more than this or he is just
> out of luck and gets huge values?
> Also, the limit will change if the type of average changes, but if it
> is calculated in the way I proposed, it will always work.
> Apart from this, since the benign possibility exists - why not to fix this
> if the fix is easy.
> 

I already explained why. Everytime you do a floating point long division 
you are potentially accumulating small errors. Something is terribly 
wrong if you are getting a diff of greater than 100,000, if that really 
is true you need to fix it right away instead of run cyclictest for a 
long period of time.

John>