Re: [PATCH 2/5] perf unwind: Do not look at globals

From: Jiri Olsa
Date: Tue Jan 16 2018 - 14:49:20 EST


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
add new global dwarf_callchain_users and work with it.. what do I miss?

I'll check tomorrow with clean head ;-)

jirka