Intel CONTROLLERS 413808 - Manual (Page 739)

Intel ® 413808 and 413812 I/O Controllers in TPER Mode
October 2007 Developer’s Manual
Order Number: 317805-001US 739
PMON Unit—Intel ® 413808 and 413812
Example 11. Head of Queue Histogram Example
A histogram can be created using two counters working together. The following applies
to all of the histogram examples:
• Start with idle system (reset counters).
• Only one slice of a histogram is measured per experiment, therefore histograms
can only be generated for repeatable workloads.
• Repeat these steps, changing threshold value and using an unchanging repeatable
workload to generate data for histogram.
This example demonstrates how often has a pre-amount of time elapsed when a
certain event takes place.
An alternative way to represent the data in the preceding table is as follow:
For X=1 to 3
Write Threshold (bucket size = X) into Data Register 0
Write Event Register 0 (Increment = QueueNotEmpty)
Write Event Register 1 (Increment = Threshold Event 0)
Start Counter 0 immediately
Restart Counter 0 (with Threshold Condition Code set to =)
whenever QueueExitEvent triggers it
Start Counter 1 immediately
Run workload
Sample Counter 1
Read Data Register 1
End For
Table 485. Head of Queue Histogram Example
Opcode Target Counter Increment Event Decrement Event Trigger Event
Write Threshold (bucket size) in Data
Register
0
Write Event Register 0 Queue Not Empty
Write Event Register 1 Threshold Event 0
Start 0 Queue Empty
Restart (CC is =) 0 Queue Exit
Start 1 Immed (000h)
-- Run Workload --
Sample 1 Immed (000h)
Read Data Register 0
-- Repeat entire sequence with new bucket
size --