User's Guide Part 2

Managing performance Chapter 6 Operation
phn-0896_009v003
6-128
UNDER DEVELOPMENT
Feb 2010
Diagnostics plotter
To further enhance the diagnostic capabilities of the PTP 600 Series, the storage of
link performance histograms has been extended to 31. To optimize RAM (volatile
memory) usage a cascading histogram approach has been adopted. The root histogram
is identical to the histograms in earlier releases of the software, that is data is stored
for one hour at a resolution of one second. Previously, the histograms were simple
cyclic buffers which never stored more that the last one hour of data. The new
cascading histogram approach daisy chains multiple histograms together. When the
first histogram fills up the overflow from the first is used as an input to the next
histogram in line. To optimize memory utilization, a statistical analysis is performed on
the overflow to reduce the amount of data to be stored. In the case of the PTP 600
Series the cascading histograms are defined as:
• Histogram 1: 1 hour at a resolution of 1 second
• Histogram 2: 24 hours at a resolution of 1 minute
• Histogram 3: 30 Days at a resolution of 1 hour
For example, when histogram 1 fills up and starts to overflow the first minute of
overflow is analyzed and the maximum, minimum and mean over that minute are
computed and inserted into histogram 2. When histogram 2 fills up and starts to
overflow the first hour of overflow is analyzed and the maximum, minimum and mean
over that hour is computed and inserted into histogram 3. When histogram 3 starts to
overflow, the overflow data is simply discarded.