I
NTEL
® X
EON
® P
ROCESSOR
7500 S
ERIES
U
NCORE
P
ROGRAMMING
G
UIDE
UNCORE PERFORMANCE MONITORING
2-127
Table 2-98. W_MSR_PMON_EVT_SEL_{3-0} Register – Field Definitions
Table 2-99. W_MSR_PMON_FIXED_CTR_CTL Register – Field Definitions
The W-Box performance monitor data registers are 48b wide. A counter overflow occurs when a carry
out bit from bit 47 is detected. Software can force all uncore counting to freeze after N events by
preloading a monitor with a count value of (2
48
- 1) - N and setting the control register to send a PMI to
the U-Box. Upon receipt of the PMI, the U-Box will disable counting (
). During the interval of time between overflow and global disable, the counter value
will wrap and continue to collect events.
In this way, software can capture the precise number of events that occurred between the time uncore
counting was enabled and when it was disabled (or ‘frozen’) with minimal skew.
If accessible, software can continuously read the data registers without disabling event collection.
Field
Bits
HW
Reset
Val
Description
ig
63
0 Read zero; writes ignored. (?)
rsv
62:61
0 Reserved; Must write to 0 else behavior is undefined.
ig
60:51
0 Read zero; writes ignored. (?)
rsv
50
0 Reserved; Must write to 0 else behavior is undefined.
ig
49:32
0 Read zero; writes ignored. (?)
thresh
31:24
0 Threshold used for counter comparison.
invert
23
0 Invert threshold comparison. When ‘0’, the comparison will be thresh >=
event. When ‘1’, the comparison will be threshold < event.
en
22
0 Counter enable
ig
21
0 Read zero; writes ignored. (?)
pmi_en
20
0 PMI Enable. If bit is set, when corresponding counter overflows, a PMI
exception is sent to the U-Box.
ig
17:16
0 Read zero; writes ignored. (?)
edge_detect
18
0 Edge Detect. When bit is set, 0->1 transition of a one bit event input will
cause counter to increment. When bit is 0, counter will increment for
however long event is asserted.
ig
17:16
0 Read zero; writes ignored. (?)
umask
15:8
0 In W-Box, this field is used to enable core scope events per core. Bit 0
masks Core 0, bit 1 masks Core 1, etc.
ev_sel
7:0
0 Event Select
Field
Bits
HW
Reset
Val
Description
ig
63:3
0 Read zero; writes ignored. (?)
rsv
2
0 Reserved; Must write to 0 else behavior is undefined.
pmi_en
1
0 PMI Enable. If bit is set, when corresponding counter overflows, a PMI
exception is sent to the U-Box.
en
0
0 Counter enable