Intel 64 and IA-32 Architectures Software Developers Manual Volume 3B, System Programming Guide Part 2

Table Of Contents
Vol. 3 18-85
DEBUGGING AND PERFORMANCE MONITORING
Edge Detect (bit 18): When set causes the counter to increment when a
deasserted to asserted transition occurs for the conditions that can be expressed
by any of the fields in this register.
PMI (bit 20): When set, the uncore will generate an interrupt request when this
counter overflowed. This request will be routed to the logical processors as
enabled in the PMI enable bits (EN_PMI_COREx) in the register
MSR_UNCORE_PERF_GLOBAL_CTRL.
EN (bit 22): When clear, this counter is locally disabled. When set, this counter is
locally enabled and counting starts when the corresponding EN_PCx bit in
MSR_UNCORE_PERF_GLOBAL_CTRL is set.
INV (bit 23): When clear, the Counter Mask field is interpreted as greater than or
equal to. When set, the Counter Mask field is interpreted as less than.
Counter Mask (bits 31:24): When this field is clear, it has no effect on counting.
When set to a value other than zero, the logical processor compares this field to
the event counts on each core clock cycle. If INV is clear and the event counts are
greater than or equal to this field, the counter is incremented by one. If INV is set
and the event counts are less than this field, the counter is incremented by one.
Otherwise the counter is not incremented.
Figure 18-33 shows the layout of MSR_UNCORE_FIXED_CTR_CTRL.
EN (bit 0): When clear, the uncore fixed-function counter is locally disabled.
When set, it is locally enabled and counting starts when the EN_FC0 bit in
MSR_UNCORE_PERF_GLOBAL_CTRL is set.
PMI (bit 2): When set, the uncore will generate an interrupt request when the
uncore fixed-function counter overflowed. This request will be routed to the
logical processors as enabled in the PMI enable bits (EN_PMI_COREx) in the
register MSR_UNCORE_PERF_GLOBAL_CTRL.
Both the general-purpose counters (MSR_UNCORE_PerfCntr) and the fixed-function
counter (MSR_UNCORE_FixedCntr0) are 48 bits wide. They support both counting
Figure 18-33. Layout of MSR_UNCORE_FIXED_CTR_CTRL MSR
87 031
Reserved
63
245
6
PMI - Generate PMI on overflow
EN - Enable
RESET Value — 0x00000000_00000000