Development Tools User’s Guide
185
Intel
®
IXP2400/IXP2800 Network Processors
Performance Monitoring Unit
3.4.3.2
Threshold Sampling Macro
Threshold macros are closely related to
Monitors
. They are used to count the number of times or
the duration that a monitor met some specified condition (typically equal to a constant). Threshold
macros use two counters. The first is a monitor. The value of this counter is compared with a
constant, and the result of this comparison becomes the input to a second counter (acting as a
monitor). So the second counter counts either the number of times or the duration that the first
counter satisfies the comparison.
Note:
The Reset on Sample option applies to the second counter; i.e. the first counter (to which the
comparison function is being applied) is always reset when a sample is taken.
Figure 63. Threshold Sampling Macro
Table 7. Threshold Sampling Macro Dialog Box
Type
Description
Reset on Sample
Specifies whether the counter is reset between samples.
Threshold
Value that is compared to the first counter.
Duration
Specifies whether the second counter is incremented once for each occurrence of the
compare function being satisfied or once for each cycle that the compare function is
satisfied. This should almost always be selected.
Compare
Function
The comapre functions are: