Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752071AbeAPUFZ (ORCPT + 1 other); Tue, 16 Jan 2018 15:05:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:36684 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750796AbeAPUFX (ORCPT ); Tue, 16 Jan 2018 15:05:23 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D086921746 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org Date: Tue, 16 Jan 2018 17:05:20 -0300 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: Ingo Molnar , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , David Ahern , Hendrick Brueckner , Namhyung Kim , Thomas Richter , Wang Nan Subject: Re: [PATCH 2/5] perf unwind: Do not look at globals Message-ID: <20180116200520.GG16107@kernel.org> References: <20180116142438.19520-1-acme@kernel.org> <20180116142438.19520-3-acme@kernel.org> <20180116151915.GC17819@krava> <20180116153621.GC16107@kernel.org> <20180116182650.GE16107@kernel.org> <20180116194909.GB6183@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180116194909.GB6183@krava> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Em Tue, Jan 16, 2018 at 08:49:09PM +0100, Jiri Olsa escreveu: > On Tue, Jan 16, 2018 at 03:26:50PM -0300, Arnaldo Carvalho de Melo wrote: > > SNIP > > > diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c > > index c0debc3f79b6..c0815a37fdb5 100644 > > --- a/tools/perf/builtin-c2c.c > > +++ b/tools/perf/builtin-c2c.c > > @@ -2390,9 +2390,10 @@ static int setup_callchain(struct perf_evlist *evlist) > > enum perf_call_graph_mode mode = CALLCHAIN_NONE; > > > > if ((sample_type & PERF_SAMPLE_REGS_USER) && > > - (sample_type & PERF_SAMPLE_STACK_USER)) > > + (sample_type & PERF_SAMPLE_STACK_USER)) { > > mode = CALLCHAIN_DWARF; > > - else if (sample_type & PERF_SAMPLE_BRANCH_STACK) > > + dwarf_callchain_users = true; > > + } else if (sample_type & PERF_SAMPLE_BRANCH_STACK) > > mode = CALLCHAIN_LBR; > > else if (sample_type & PERF_SAMPLE_CALLCHAIN) > > mode = CALLCHAIN_FP; > > diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c > > index dd4df9a5cd06..6593779224d5 100644 > > --- a/tools/perf/builtin-report.c > > +++ b/tools/perf/builtin-report.c > > @@ -338,9 +338,10 @@ static int report__setup_sample_type(struct report *rep) > > > > if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) { > > if ((sample_type & PERF_SAMPLE_REGS_USER) && > > - (sample_type & PERF_SAMPLE_STACK_USER)) > > + (sample_type & PERF_SAMPLE_STACK_USER)) { > > callchain_param.record_mode = CALLCHAIN_DWARF; > > - else if (sample_type & PERF_SAMPLE_BRANCH_STACK) > > + dwarf_callchain_users = true; > > + } else if (sample_type & PERF_SAMPLE_BRANCH_STACK) > > callchain_param.record_mode = CALLCHAIN_LBR; > > else > > callchain_param.record_mode = CALLCHAIN_FP; > > diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c > > index c1cce474c0f1..08bc818f371b 100644 > > --- a/tools/perf/builtin-script.c > > +++ b/tools/perf/builtin-script.c > > @@ -2919,9 +2919,10 @@ static void script__setup_sample_type(struct perf_script *script) > > > > if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) { > > if ((sample_type & PERF_SAMPLE_REGS_USER) && > > - (sample_type & PERF_SAMPLE_STACK_USER)) > > + (sample_type & PERF_SAMPLE_STACK_USER)) { > > callchain_param.record_mode = CALLCHAIN_DWARF; > > - else if (sample_type & PERF_SAMPLE_BRANCH_STACK) > > + dwarf_callchain_users = true; > > + } else if (sample_type & PERF_SAMPLE_BRANCH_STACK) > > callchain_param.record_mode = CALLCHAIN_LBR; > > else > > callchain_param.record_mode = CALLCHAIN_FP; > > diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c > > index ac40e05bcab4..260418969120 100644 > > --- a/tools/perf/tests/dwarf-unwind.c > > +++ b/tools/perf/tests/dwarf-unwind.c > > @@ -173,6 +173,7 @@ int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unu > > } > > > > callchain_param.record_mode = CALLCHAIN_DWARF; > > + dwarf_callchain_users = true; > > > > if (init_live_machine(machine)) { > > pr_err("Could not init machine\n"); > > diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c > > index 082505d08d72..32ef7bdca1cf 100644 > > --- a/tools/perf/util/callchain.c > > +++ b/tools/perf/util/callchain.c > > @@ -37,6 +37,15 @@ struct callchain_param callchain_param = { > > CALLCHAIN_PARAM_DEFAULT > > }; > > > > +/* > > + * Are there any events usind DWARF callchains? > > + * > > + * I.e. > > + * > > + * -e cycles/call-graph=dwarf/ > > + */ > > +bool dwarf_callchain_users; > > hum, I don't follow.. this bool seems to mirror the usage of > 'param->record_mode = CALLCHAIN_DWARF', whats the difference? > > also, the patch title says 'Do not look at globals', while inside you The first version didn't look at globals, the second one doesn't look at an _specific_ global variable, the global config for --call-graph, which is a global variable, callchain_param, which _we_ can't touch at apply_config_terms(), since that is about _just_ that event, not all of them. > add new global dwarf_callchain_users and work with it.. what do I miss? > > I'll check tomorrow with clean head ;-) Look closely at apply_config_terms() it passes a _local_ variable to perf_evsel__config_callchain(evsel, opts, ¶m); It will not affect any globals that tools/perf/util/unwind-libunwind-local.c could possibly use... and that is the problem. :-) The right fix, as I said, is more involved and may allow us to remove these two global variables, both callchain_param and dwarf_callchain_users. We need to have per-evsel unwind ops, per thread addr_space continues to be used by the dwarf unwinder _for the events sampled in that thread_, etc. The prepare_unwind is to be made to evsel and thread (for thread we need to look at one of its executable maps, to determine if it is 32-bit or 64-bit, etc, but not necessarily at that insert_map part, etc). - Arnaldo