BCC - Tools for BPF-based Linux IO analysis, networking, monitoring, and more
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yonghong-song fix compilation error with llvm trunk (8.0.0) (#1924)
LLVM commit https://reviews.llvm.org/D49741 removed
function DEARFContext::getCompileUnitAtIndex() and caused
the bcc compilation failure.

Change usage of getCompileUnitAtIndex() to the one
recommended in the above llvm commit.

Signed-off-by: Yonghong Song <yhs@fb.com>
Latest commit 0284325 Aug 13, 2018
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SPECS Fedora 28 support (#1820) Jul 23, 2018
cmake Fedora 28 support (#1820) Jul 23, 2018
debian Prepare debian changelog for v0.6.1 tag Jul 23, 2018
docs Documentation: Added table for program type and its helper functions (#… Aug 7, 2018
examples Update scripts to use `increment` (#1905) Aug 1, 2018
images update tools diagram Apr 3, 2017
introspection add missing types in bps Jun 11, 2018
man sslsniff: add NSS support (#1908) Aug 4, 2018
scripts Fedora 28 support (#1820) Jul 23, 2018
snapcraft Upgrade llvm toolchain version Feb 24, 2018
src fix compilation error with llvm trunk (8.0.0) (#1924) Aug 13, 2018
tests python3 fixes and testing support (#1916) Aug 9, 2018
tools Merge pull request #1918 from jeromemarchand/llcstat Aug 9, 2018
.clang-format Add TableStorage class for wrapping bpf map tracking Apr 3, 2017
.dockerignore Add multiple build support styles Jul 7, 2015
.gitignore Debian jessie compile/test work in progress. Feb 9, 2017
.travis.yml Script to check that the lists of helpers are in sync Feb 14, 2018
CMakeLists.txt Fedora 28 support (#1820) Jul 23, 2018
CODEOWNERS Add /tests/ to CODEOWNERS Aug 23, 2017
CONTRIBUTING-SCRIPTS.md Mention the smoke tests for new tool contributions Sep 4, 2017
Dockerfile.debian Fixes for debian and ubuntu docker build Aug 17, 2017
Dockerfile.ubuntu Fixes for debian and ubuntu docker build Aug 17, 2017
FAQ.txt Updated the FAQ with the error produced if python[2-3]-bcc isn't inst… Feb 5, 2018
INSTALL.md Adding Fedora 28 to the list of fedora versions (#1898) Aug 9, 2018
LICENSE.txt Create LICENSE.txt Jun 5, 2015
LINKS.md Link to article on how Circonus uses bcc May 8, 2018
QUICKSTART.md add Quick Start Guide for bcc docker Dec 1, 2016
README.md bcc: criticalstat: Add an atomic critical section tracer (#1801) Jun 19, 2018


BCC Logo

BPF Compiler Collection (BCC)

BCC is a toolkit for creating efficient kernel tracing and manipulation programs, and includes several useful tools and examples. It makes use of extended BPF (Berkeley Packet Filters), formally known as eBPF, a new feature that was first added to Linux 3.15. Much of what BCC uses requires Linux 4.1 and above.

eBPF was described by Ingo Molnár as:

One of the more interesting features in this cycle is the ability to attach eBPF programs (user-defined, sandboxed bytecode executed by the kernel) to kprobes. This allows user-defined instrumentation on a live kernel image that can never crash, hang or interfere with the kernel negatively.

BCC makes BPF programs easier to write, with kernel instrumentation in C (and includes a C wrapper around LLVM), and front-ends in Python and lua. It is suited for many tasks, including performance analysis and network traffic control.


This example traces a disk I/O kernel function, and populates an in-kernel power-of-2 histogram of the I/O size. For efficiency, only the histogram summary is returned to user-level.

# ./bitehist.py
Tracing... Hit Ctrl-C to end.
     kbytes          : count     distribution
       0 -> 1        : 3        |                                      |
       2 -> 3        : 0        |                                      |
       4 -> 7        : 211      |**********                            |
       8 -> 15       : 0        |                                      |
      16 -> 31       : 0        |                                      |
      32 -> 63       : 0        |                                      |
      64 -> 127      : 1        |                                      |
     128 -> 255      : 800      |**************************************|

The above output shows a bimodal distribution, where the largest mode of 800 I/O was between 128 and 255 Kbytes in size.

See the source: bitehist.py. What this traces, what this stores, and how the data is presented, can be entirely customized. This shows only some of many possible capabilities.


See INSTALL.md for installation steps on your platform.


See FAQ.txt for the most common troubleshoot questions.

Reference guide

See docs/reference_guide.md for the reference guide to the bcc and bcc/BPF APIs.


Some of these are single files that contain both C and Python, others have a pair of .c and .py files, and some are directories of files.






BPF Introspection:

Tools that help to introspect BPF programs.

  • introspection/bps.c: List all BPF programs loaded into the kernel. 'ps' for BPF programs. Examples.


BPF guarantees that the programs loaded into the kernel cannot crash, and cannot run forever, but yet BPF is general purpose enough to perform many arbitrary types of computation. Currently, it is possible to write a program in C that will compile into a valid BPF program, yet it is vastly easier to write a C program that will compile into invalid BPF (C is like that). The user won't know until trying to run the program whether it was valid or not.

With a BPF-specific frontend, one should be able to write in a language and receive feedback from the compiler on the validity as it pertains to a BPF backend. This toolkit aims to provide a frontend that can only create valid BPF programs while still harnessing its full flexibility.

Furthermore, current integrations with BPF have a kludgy workflow, sometimes involving compiling directly in a linux kernel source tree. This toolchain aims to minimize the time that a developer spends getting BPF compiled, and instead focus on the applications that can be written and the problems that can be solved with BPF.

The features of this toolkit include:

  • End-to-end BPF workflow in a shared library
    • A modified C language for BPF backends
    • Integration with llvm-bpf backend for JIT
    • Dynamic (un)loading of JITed programs
    • Support for BPF kernel hooks: socket filters, tc classifiers, tc actions, and kprobes
  • Bindings for Python
  • Examples for socket filters, tc classifiers, and kprobes
  • Self-contained tools for tracing a running system

In the future, more bindings besides python will likely be supported. Feel free to add support for the language of your choice and send a pull request!



At Red Hat Summit 2015, BCC was presented as part of a session on BPF. A multi-host vxlan environment is simulated and a BPF program used to monitor one of the physical interfaces. The BPF program keeps statistics on the inner and outer IP addresses traversing the interface, and the userspace component turns those statistics into a graph showing the traffic distribution at multiple granularities. See the code here.



Already pumped up to commit some code? Here are some resources to join the discussions in the IOVisor community and see what you want to work on.

External links

Looking for more information on BCC and how it's being used? You can find links to other BCC content on the web in LINKS.md.