On Wed, Mar 18, 2020 at 09:11:34PM -0700, Ian Rogers wrote:

This patch links perf with the libpfm4 library if it is available and
NO_LIBPFM4 isn't passed to the build. The libpfm4 library contains hardware
event tables for all processors supported by perf_events. It is a helper
library that helps convert from a symbolic event name to the event
encoding required by the underlying kernel interface. This
library is open-source and available from: http://perfmon2.sf.net.

With this patch, it is possible to specify full hardware events
by name. Hardware filters are also supported. Events must be
specified via the --pfm-events and not -e option. Both options
are active at the same time and it is possible to mix and match:

$ perf stat --pfm-events inst_retired:any_p:c=1:i -e cycles ....

v4 is a rebase on git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git
   branch perf/core and re-adds the tools/build/feature/test-libpfm4.c
   missed in v3.

ugh.. I might have waited too long, but I can't apply it
anymore on Arnaldo's perf/core, sorry

jirka