Commit 6bedfab6 authored by Jiri Olsa's avatar Jiri Olsa Committed by Ingo Molnar
Browse files

perf tools: Disable user-space callchain/stack dumps for function trace events 

User space callchains and user space stack dump were disabled
for function trace event. Mailing list discussions:

  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2



Catching up with perf and disabling user space callchains and
DWARF unwind (uses user stack dump) for function trace event.

Adding following warnings when callchains are used
for function trace event:

  # perf record -g -e ftrace:function ...
  Disabling user space callchains for function trace event.
  ...

  # ./perf record --call-graph=dwarf -e ftrace:function ...
  Cannot use DWARF unwind for function trace event, falling back to framepointers.
  Disabling user space callchains for function trace event.
  ...

Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1393775800-13524-4-git-send-email-jolsa@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 63c45f4b

tools/perf/util/evsel.c

+30 −11
Original line number Diff line number Diff line
@@ -500,6 +500,34 @@ int perf_evsel__group_desc(struct perf_evsel *evsel, char *buf, size_t size) 
	return ret;

}



static void

perf_evsel__config_callgraph(struct perf_evsel *evsel,

			     struct record_opts *opts)

{

	bool function = perf_evsel__is_function_event(evsel);

	struct perf_event_attr *attr = &evsel->attr;



	perf_evsel__set_sample_bit(evsel, CALLCHAIN);



	if (opts->call_graph == CALLCHAIN_DWARF) {

		if (!function) {

			perf_evsel__set_sample_bit(evsel, REGS_USER);

			perf_evsel__set_sample_bit(evsel, STACK_USER);

			attr->sample_regs_user = PERF_REGS_MASK;

			attr->sample_stack_user = opts->stack_dump_size;

			attr->exclude_callchain_user = 1;

		} else {

			pr_info("Cannot use DWARF unwind for function trace event,"

				" falling back to framepointers.\n");

		}

	}



	if (function) {

		pr_info("Disabling user space callchains for function trace event.\n");

		attr->exclude_callchain_user = 1;

	}

}



/*

 * The enable_on_exec/disabled value strategy:

 *
@@ -595,17 +623,8 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts) 
		attr->mmap_data = track;

	}



	if (opts->call_graph_enabled) {

		perf_evsel__set_sample_bit(evsel, CALLCHAIN);



		if (opts->call_graph == CALLCHAIN_DWARF) {

			perf_evsel__set_sample_bit(evsel, REGS_USER);

			perf_evsel__set_sample_bit(evsel, STACK_USER);

			attr->sample_regs_user = PERF_REGS_MASK;

			attr->sample_stack_user = opts->stack_dump_size;

			attr->exclude_callchain_user = 1;

		}

	}

	if (opts->call_graph_enabled)

		perf_evsel__config_callgraph(evsel, opts);



	if (target__has_cpu(&opts->target))

		perf_evsel__set_sample_bit(evsel, CPU);

tools/perf/util/evsel.h

+18 −0
Original line number Diff line number Diff line
@@ -315,6 +315,24 @@ static inline bool perf_evsel__is_group_event(struct perf_evsel *evsel) 
	return perf_evsel__is_group_leader(evsel) && evsel->nr_members > 1;

}



/**

 * perf_evsel__is_function_event - Return whether given evsel is a function

 * trace event

 *

 * @evsel - evsel selector to be tested

 *

 * Return %true if event is function trace event

 */

static inline bool perf_evsel__is_function_event(struct perf_evsel *evsel)

{

#define FUNCTION_EVENT "ftrace:function"



	return evsel->name &&

	       !strncmp(FUNCTION_EVENT, evsel->name, sizeof(FUNCTION_EVENT));



#undef FUNCTION_EVENT

}



struct perf_attr_details {

	bool freq;

	bool verbose;

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