---
name: "xfsdist.bt"
section: "8"
platform: "linux"
package: "bpftrace"
version: "0.27.0-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/xfsdist.bt"
---

# xfsdist.bt(8)

Summarize XFS operation latency. Uses bpftrace/eBPF.

## NAME

xfsdist.bt - Summarize XFS operation latency. Uses bpftrace/eBPF.

## SYNOPSIS

**xfsdist.bt**

## DESCRIPTION

This tool summarizes time (latency) spent in common XFS file operations: reads, writes, opens, and syncs, and presents it as a power-of-2 histogram. It uses an in-kernel eBPF map to store the histogram for efficiency.

Since this works by tracing the xfs\_file\_operations interface functions, it will need updating to match any changes to these functions.

Since this uses BPF, only the root user can use this tool.

## REQUIREMENTS

CONFIG\_BPF and bpftrace.

## EXAMPLES

- Trace XFS operation time, and print a summary on Ctrl-C:

  \# **xfsdist.bt**

## FIELDS

- 0th

  The operation name (shown in "@\[...\]") is printed before each I/O histogram.

- 1st, 2nd

  This is a range of latency, in microseconds (shown in "\[...)" set notation).

- 3rd

  A column showing the count of operations in this range.

- 4th

  This is an ASCII histogram representing the count column.

## OVERHEAD

This adds low-overhead instrumentation to these XFS operations, including reads and writes from the file system cache. Such reads and writes can be very frequent (depending on the workload; eg, 1M/sec), at which point the overhead of this tool may become noticeable. Measure and quantify before use.

## SOURCE

This is from bpftrace.

-

  https://github.com/bpftrace/bpftrace

Also look in the bpftrace distribution for a companion \_examples.txt file containing example usage, output, and commentary for this tool.

This is a bpftrace version of the bcc tool of the same name. The bcc tool may provide more options and customizations.

-

  https://github.com/iovisor/bcc

## OS

Linux

## STABILITY

Unstable - in development.

## AUTHOR

Brendan Gregg

## SEE ALSO

[biolatency.bt(8)](/biolatency.bt/8.md)