From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: * X-Spam-Status: No, score=1.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RDNS_NONE,SPF_HELO_NONE,SPF_NONE autolearn=no autolearn_force=no version=3.4.0 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:21990 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730264AbgCKQNz (ORCPT ); Wed, 11 Mar 2020 12:13:55 -0400 Date: Wed, 11 Mar 2020 17:13:20 +0100 From: Jiri Olsa To: Stephane Eranian Cc: Andi Kleen , Ian Rogers , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Yonghong Song , Andrii Nakryiko , Greg Kroah-Hartman , Thomas Gleixner , Igor Lubashev , Alexey Budankov , Florian Fainelli , Adrian Hunter , Jiwei Sun , yuzhoujian , Kan Liang , Jin Yao , Leo Yan , John Garry , LKML , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH] perf tools: add support for lipfm4 Message-ID: <20200311161320.GA254105@krava> References: <20200310185003.57344-1-irogers@google.com> <20200310195915.GA1676879@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: On Tue, Mar 10, 2020 at 02:39:23PM -0700, Stephane Eranian wrote: > On Tue, Mar 10, 2020 at 12:59 PM Andi Kleen 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