perf_event ABI breakage

perf_event has a unique design philosophy. Part of that involves having the source code for the flagship perf tool included in the Linux kernel source tree. The claim is that this will enhance the ABI. In practice the ABI is frequently broken, and as long as the userspace perf tool still works none of the kernel developers seem to notice or care.

The sysfs layout is particularly troublesome. Some of the files are documented in Documentation/ABI/testing/ but since it is "testing" the developers don't feel the need to keep things stable.

What follows is a list of recent ABI breakage. I haven't included things from the early pre-2.6.34 days (perf support started with 2.6.31) as any new interface takes a while to shake out. Those early kernels did have problems though, and PAPI still carries the workaround for them.

4.0

3.18

3.14


3.10


3.7


3.3


3.2


3.0


2.6.38


2.6.37


2.6.34


See also: Built-in Kernel Event Changes
Back to unofficial perf_event page