Floating point problem

[Martin Spier <mspier@xxxxxxxxxxx>]

Ran into a small problem with "value" floating point precision on pmwebd json responses.

Cumulative values get too big and I start having problems like this:

{

 "timestamp": {

  "s": 1406323733,

  "us": 288692

 },

 "values": [

  {

   "pmid": 2143289348,

   "name": "kernel.pct.cpu.user",

   "instances": [

    {

     "value": 7.94874E+10

    }

   ]

  }

 ]

}

Since I'm trying to calculate % usage in this case, subtracting previous value from current and normalizing by delta in time, at this point I can't get any useful information to plot due to the low precision.

Any suggestions?

-Martin