On Wed, Mar 11, 2020 at 9:13 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > On Tue, Mar 10, 2020 at 02:39:23PM -0700, Stephane Eranian wrote: > > On Tue, Mar 10, 2020 at 12:59 PM Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote: > > > > > > On Tue, Mar 10, 2020 at 11:50:03AM -0700, Ian Rogers wrote: > > > > This patch links perf with the libpfm4 library. > > > > This library contains all the hardware event tables for all > > > > processors supported by perf_events. This is a helper library > > > > that help 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. > > > > > > For most CPUs the builtin perf JSON event support should make > > > this redundant. > > > > > We decided to post this patch to propose an alternative to the JSON > > file approach. It could be an option during the build. > > The libpfm4 library has been around for 15 years now. Therefore, it > > supports a lot of processors core and uncore and it is very portable. > > The key value add I see is that this is a library that can be, and has > > been, used by tool developers directly in their apps. It can > > work with more than Linux perf_events interface. It is not tied to the > > interface. It has well defined and documented entry points. > > We do use libpfm4 extensively at Google in both the perf tool and > > applications. The PAPI toolkit also relies on this library. > > > > I don't see this as competing with the JSON approach. It is just an > > option I'd like to offer to users especially those familiar > > with it in their apps. > > I dont mind having it, in fact I found really old email where I'm > asking Peter about that ;-) and he wasn't very keen about that: > https://lore.kernel.org/lkml/1312806326.10488.30.camel@twins/ > > not sure what was the actual reason at that time and if anything > changed since.. Peter? > > btw I can't apply even that v2 on latest Arnaldo's branch > > jirka Thanks Jiri, the patches were done on tip.git/master, perhaps there is a conflict with the Documents Makefile due to adding better man page dates? I'll try to repro building on https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/ on the perf/core branch unless you have a different suggestion? I also noticed a warning crept into the Makefile.config in the v2 patch set that should be removed. Ian
