pmc.ucf(3)

pmc.ucf3

Measurement events for intel uncore fixed function performance counters.

Usage

#include <pmc.h>

Library

library “libpmc”

Overview

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:

CapabilitySupport
PMC_CAP_CASCADENo
PMC_CAP_EDGENo
PMC_CAP_INTERRUPTNo
PMC_CAP_INVERTNo
PMC_CAP_READYes
PMC_CAP_PRECISENo
PMC_CAP_SYSTEMNo
PMC_CAP_TAGGINGNo
PMC_CAP_THRESHOLDNo
PMC_CAP_USERNo
PMC_CAP_WRITEYes

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.

Releases

39 releases since FreeBSD 7.4-RELEASE; the text changed 28 times.

  1. 7.4
  2. 8.1
  3. 8.2
  4. 8.3
  5. 8.4
  6. 9.0
  7. 9.1
  8. 9.2
  9. 9.3
  10. 10.0
  11. 10.1
  12. 10.2
  13. 10.3
  14. 10.4
  15. 11.0
  16. 11.1
  17. 11.2
  18. 11.3
  19. 11.4
  20. 12.0
  21. 12.1
  22. 12.2
  23. 12.3
  24. 12.4
  25. 13.0
  26. 13.1–13.2
  27. 13.3–14.5
  28. 15.0–15.1
  29. 16.0

History

The pmc library first appeared in FreeBSD 6.0.

Authors

The library “libpmc” library was written by Joseph Koshy ⟨[email protected]⟩.

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.