PMC_ENABLE(3)

💖 NAME 💖

Okay so welcome to the PMC_ENABLE(3) page from the Library Functions Manual, bestie — this is the whole administrative control of hardware performance counters situation.

pmc_disable, pmc_enable — administrative control of hardware performance counters 💅

---

🎀 LIBRARY 🎀

Performance Counters Library (libpmc, -lpmc) ✨

---

🌸 SYNOPSIS 🌸

#include <pmc.h>

int
pmc_disable(int cpu, int pmc);

int
pmc_enable(int cpu, int pmc);

---

🦋 DESCRIPTION 🦋

These functions let you disable and enable specific hardware performance monitoring counters in a system administratively — like, you're doing admin things to the counters, no cap.

The hardware performance counters available on each CPU are numbered using small non-negative integers, in a system dependent manner. Disabled counters will not be available to applications for use — periodt, they're off the menu 😭.

The invoking process needs to have the PRIV_PMC_MANAGE privilege to perform these operations. No privilege, no counter management — them's the rules 🔥.

Function pmc_disable() disables the hardware counter numbered by argument pmc on CPU number cpu.

Function pmc_enable() enables the hardware counter numbered by argument pmc on CPU number cpu.

---

🧚 IMPLEMENTATION NOTES 🧚

Heads up, bestie: hardware PMCs that are currently in use by applications cannot be disabled.

Allocation of a process scope software PMC marks all hardware PMCs in the system with the same pmc number as being in-use. So yeah, that's a whole vibe check for the counters 😌.

---

🫶 RETURN VALUES 🫶

Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error. Slay when it's zero, sigh when it's minus one 💀.

---

💀 ERRORS 💀

A call to these functions may fail with the following errors:

• [EBUSY] — Function pmc_disable() specified a hardware PMC that is currently in use.
• [EINVAL] — Arguments cpu or pmc were invalid.
• [ENXIO] — Argument cpu specified a disabled or absent CPU.
• [EPERM] — The current process lacks sufficient privilege to perform this operation.

---

🔥 SEE ALSO 🔥

Go peek at these, iykyk: pmc(3), pmc_cpuinfo(3), pmc_pmcinfo(3), hwpmc(4), pmccontrol(8), priv_check(9) 🦋✨

---

And that's the tea ☕: this is the Debian edition, dated September 22, 2008, for PMC_ENABLE(3) — stay iconic and keep those counters handled, bestie 💖🫶👑