DESCRIPTION
Each fixed-function PMC measures a specific hardware event. The number of fixed-function PMCs implemented in a CPU can vary. The number of fixed-function PMCs present can be determined at runtime by using function
pmc_cpuinfo(3).
Intel uncore fixed-function PMCs are documented in Volume 3B: System Programming Guide, Part 2, Intel(R) 64 and IA-32 Architectures Software Developes Manual, Order Number: 253669-033US, Intel Corporation, December 2009.
PMC Capabilities
Fixed-function PMCs support the following capabilities:
| Capability |
Support |
| PMC_CAP_CASCADE |
No |
| PMC_CAP_EDGE |
No |
| PMC_CAP_INTERRUPT |
No |
| PMC_CAP_INVERT |
No |
| PMC_CAP_READ |
Yes |
| PMC_CAP_PRECISE |
No |
| PMC_CAP_SYSTEM |
No |
| PMC_CAP_TAGGING |
No |
| PMC_CAP_THRESHOLD |
No |
| PMC_CAP_USER |
No |
| PMC_CAP_WRITE |
Yes |
Class Name Prefix
These PMCs are named using a class name prefix of “
ucf-”.
Event Specifiers (Fixed Function PMCs)
The fixed function PMCs are selectable using the following event names:
-
UCLOCK
-
(Fixed Function Counter 0) The fixed-function uncore counter increments at the rate of the U-clock. The frequency of the uncore clock domain can be determined from the uncore clock ratio which is available in the PCI configuration space register at offset C0H under device number 0 and Function 0.