The goal of the perfmon2 project is to provide a standard interface in the Linux kernel to access the hardware performance counters of all modern processors. The project has been in development for several years and has now reached a satisfactory level of features: counting and sampling in per-thread and per-cpu modes, multiplexing of event sets, customizable in-kernel sampling buffers. All major processors architectures are supported, thanks to contributions from many developers. Advanced hardware features such as Intel PEBS and AMD IBS are also supported.

A detailed overview of the interface was presented at the previous edition of this workshop. This year, we provide an update on the status of the interface. We describe what has changed since last year and we address the sticking issue of the merge with the mainline Linux kernel and in particular: where we are, what are the concerns, how we are addressing them, what is a possible time line.