1What: /sys/kernel/debug/tracing 2Date: May 2008 3KernelVersion: 2.6.27 4Contact: linux-trace-kernel@vger.kernel.org 5Description: 6 7 The ftrace was first added to the kernel, its interface was placed 8 into the debugfs file system under the "tracing" directory. Access 9 to the files were in /sys/kernel/debug/tracing. As systems wanted 10 access to the tracing interface without having to enable debugfs, a 11 new interface was created called "tracefs". This was a stand alone 12 file system and was usually mounted in /sys/kernel/tracing. 13 14 To allow older tooling to continue to operate, when mounting 15 debugfs, the tracefs file system would automatically get mounted in 16 the "tracing" directory of debugfs. The tracefs interface was added 17 in January 2015 in the v4.1 kernel. 18 19 All tooling should now be using tracefs directly and the "tracing" 20 directory in debugfs should be removed by January 2030. 21