---
name: "dtrace_profile"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/dtrace_profile"
---

# dtrace\_profile(4)

a DTrace provider for firing probes at a given time interval

## NAME

**dtrace\_profile** – a DTrace provider for firing probes at a given time interval

## SYNOPSIS

**profile****:::profile-***rate*\[*unit*\]

**profile****:::tick-***rate*\[*unit*\]

## DESCRIPTION

The **profile** provider implements three special probes related to the life cycle of the DTrace program itself.

### Probes

The **profile****:::profile** probes fire on all CPUs and are suitable for measuring the whole system periodically.

The **profile****:::tick** probes fire on a single CPU, potentially a different one every time. They are useful, e.g., for printing partial results periodically.

### Rate and Time Units

The **profile** provider probes will fire at the specified *rate*.

The default unit is **hz**. The **profile** provider supports the following time units:

| | |
| --- | --- |
| **Time** **Unit** | **Definition** |
| **ns**, **nsec** | nanoseconds |
| **us**, **usec** | microseconds |
| **ms**, **msec** | milliseconds |
| **s**, **sec** | seconds |
| **m**, **min** | minutes |
| **h**, **hour** | hours |
| **d**, **day** | days |
| **hz** | Hertz (frequency per second) |

### Probe Arguments

The arguments of the **profile** provider probes are:

- *arg0*

  The PC (program counter) in the kernel when the probe triggered, or 0 if the process was not in the kernel at that time.

- *arg1*

  The PC in the user process when the probe triggered, or 0 if the process was in the kernel when the probe triggered.

Use arguments *arg0* and *arg1* to tell if the **profile** provider probe fired in the kernel or in the userspace context.

## IMPLEMENTATION NOTES

The [sysctl(8)](/sysctl/8.md) variable *kern.dtrace.profile.aframes* controls the number of skipped artificial frames for the **profile** provider.

## EXAMPLES

### Example 1 : Profiling On-CPU Kernel Stack Traces

The following DTrace one-liner uses the **profile** provider to collect stack traces over 60 seconds.

```
dtrace -x stackframes=100 -n 'profile-197 /arg0/ {@[stack()] = count();} tick-60s {exit(0);}
```

The system is profiled at the 197 Hz to avoid sampling in lockstep with other periodic activities. This unnatural frequency minimizes the chance of overlapping with other events.

Option **-x** **stackframes=100** increases the maximum number of kernel stack frames to unwind during **stack**().

Checking if *arg0* is not zero makes sure that profiling happens when the program is in the kernel context.

Refer to **https://www.brendangregg.com/flamegraphs.html** to learn about generating flame graphs from the obtained stack traces.

## SEE ALSO

[dtrace(1)](/dtrace/1.md), [tracing(7)](/tracing/7.md) *The illumos Dynamic Tracing Guide*, 2008, Chapter profile Provider, https://www.illumos.org/books/dtrace/chp-profile.html. Brendan Gregg and Jim Mauro, *DTrace: Dynamic Tracing in Oracle Solaris, Mac OS X and FreeBSD*, Prentice Hall, pp. 24–25, 2011, https://www.brendangregg.com/dtracebook/.

## AUTHORS

This manual page was written by Mateusz Piotrowski ⟨*0mp@FreeBSD.org*⟩.