Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
947
PMON Unit—Intel
®
81341 and 81342
18.0
PMON Unit
18.1
PMON Counters
The Performance Monitoring (
PMON
) counters enable performance monitoring and
gathering statistics of internal hardware events in real-time. This implementation
provides users with direct event counting and timing for performance monitoring and
system debugging purposes. It provides enough visibility into the internal architecture
to perform utilization studies, workload characterization, and application tuning.
18.2
Overview
At the heart of the
PMON
functionality are counters with associated registers. Each
counter has a corresponding command, event, status, and data register. The
PMON
unit implements eight counters.
Signals representing events from throughout the chip are routed to the
PMON
unit.
Software can select which events are recorded during a measurement session. The
starting, stopping, and sampling of the counters can be controlled by either software or
hardware. This can be done in a time-based (polling) or event-based fashion. Each
counter can be incremented or decremented by different events. In addition to simple
counting of events the unit can provide data for histograms, queue analysis, and
conditional event counting (example: How many times did event A happen before the
first event B took place).
Figure 155. Example Block Diagram of Component with Counter
S
E
L
E
C
T
L
O
G
IC
COUNTERS
+ / -
+ / -
+ / -
Indicator Output Pin
Programming
Interface
.
.
.
Event
Inputs
B6296-01