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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_NONE,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 8F89C7D918 for ; Wed, 11 Mar 2020 16:13:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730246AbgCKQNy (ORCPT ); Wed, 11 Mar 2020 12:13:54 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:55135 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730248AbgCKQNx (ORCPT ); Wed, 11 Mar 2020 12:13:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583943232; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=C2dn7dDfcp/5qsKW13nLYAsv37ZI1/+LekwqWkQ/smk=; b=EgqmOoQHKFpPx7nDexAl8sZiCoLGJnSYSJ3JbgBLPDWTHgjrarEV/YNOWDSF2Gj4wGG+vG OjvRWrzS2AsNJL+o00LiMzZXE3vyPaJoEieB8TFuTbGKhIu7Wt1W6NZh1ajk/gaMV+b9UH 0wuUueKK2buH9gbz+TAJTTeXdUrBEG0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-152-31R9xhpePXm_8X4A4fDqgQ-1; Wed, 11 Mar 2020 12:13:45 -0400 X-MC-Unique: 31R9xhpePXm_8X4A4fDqgQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 37D8CDB21; Wed, 11 Mar 2020 16:13:42 +0000 (UTC) Received: from krava (ovpn-204-40.brq.redhat.com [10.40.204.40]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 06C818F354; Wed, 11 Mar 2020 16:13:34 +0000 (UTC) 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: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Archived-At: List-Archive: List-Post: 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