I
NTEL
® X
EON
® P
ROCESSOR
7500 S
ERIES
U
NCORE
P
ROGRAMMING
G
UIDE
UNCORE PERFORMANCE MONITORING
2-126
Table 2-96. W_MSR_PMON_GLOBAL_STATUS Register Fields
Table 2-97. W_MSR_PMON_GLOBAL_OVF_CTRL Register Fields
2.8.3.2
W-Box PMON state - Counter/Control Pairs
The following table defines the layout of the W-Box performance monitor control registers. The main
task of these configuration registers is to select the event to be monitored by their respective data
counter. Setting the .ev_sel and .umask fields performs the event selection. The .en bit must be set to
1 to enable counting.
Additional control bits include:
- .pmi_enable governs what to do if an overflow is detected.
- .threshold - since C-Box counters can increment by a value greater than 1, a threshold can be applied.
If the .threshold is set to a non-zero value, that value is compared against the incoming count for that
event in each cycle. If the incoming count is >= the threshold value, then the event count captured in
the data register will be incremented by 1. (Not present in fixed counter)
- .invert - Changes the .threshold test condition to ‘<‘ (Not present in fixed counter)
- .edge_detect - Rather than accumulating the raw count each cycle (for events that can increment by
1 per cycle), the register can capture transitions from no event to an event incoming. (Not present in
fixed counter)
Field
Bits
HW
Reset
Val
Description
ov_fixed
31
0 If an overflow is detected from the WBOX PMON fixed counter, this bit
will be set.
ig
30:4
0 Read zero; writes ignored. (?)
ov
3:0
0 If an overflow is detected from the corresponding WBOX PMON
register, it’s overflow bit will be set.
Field
Bits
HW
Reset
Val
Description
clr_ov_fixed
31
0 Writing ‘1’ to bit in field causes corresponding bit in ‘Overflow PerfMon
Counter’ field in W_MSR_PMON_GLOBAL_STATUS register to be
cleared to 0.
ig
30:4
0 Read zero; writes ignored. (?)
clr_ov
5:0
0 Writing ‘1’ to bit in field causes corresponding bit in ‘Overflow PerfMon
Counter’ field in W_MSR_PMON_GLOBAL_STATUS register to be
cleared to 0.