Commit f0a0251c authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf intel-pt: Add support for synthesizing branch stacks for regular events 



Use the new thread_stack__br_sample_late() function to create a thread
stack for regular events.

Example:

 # perf record --kcore --aux-sample -e '{intel_pt//,cycles:ppp}' -c 10000 uname
 Linux
 [ perf record: Woken up 2 times to write data ]
 [ perf record: Captured and wrote 0.743 MB perf.data ]
 # perf report --itrace=Le --stdio | head -30 | tail -18

 # Samples: 11K of event 'cycles:ppp'
 # Event count (approx.): 11648
 #
 # Overhead  Command  Source Shared Object  Source Symbol                 Target Symbol                 Basic Block Cycles
 # ........  .......  ....................  ............................  ............................  ..................
 #
      5.49%  uname    libc-2.30.so          [.] _dl_addr                  [.] _dl_addr                  -
      2.41%  uname    ld-2.30.so            [.] _dl_relocate_object       [.] _dl_relocate_object       -
      2.31%  uname    ld-2.30.so            [.] do_lookup_x               [.] do_lookup_x               -
      2.17%  uname    [kernel.kallsyms]     [k] unmap_page_range          [k] unmap_page_range          -
      2.05%  uname    ld-2.30.so            [k] _dl_start                 [k] _dl_start                 -
      1.97%  uname    ld-2.30.so            [.] _dl_lookup_symbol_x       [.] _dl_lookup_symbol_x       -
      1.94%  uname    [kernel.kallsyms]     [k] filemap_map_pages         [k] filemap_map_pages         -
      1.60%  uname    [kernel.kallsyms]     [k] __handle_mm_fault         [k] __handle_mm_fault         -
      1.44%  uname    [kernel.kallsyms]     [k] page_add_file_rmap        [k] page_add_file_rmap        -
      1.12%  uname    [kernel.kallsyms]     [k] vma_interval_tree_insert  [k] vma_interval_tree_insert  -
      0.94%  uname    [kernel.kallsyms]     [k] perf_iterate_ctx          [k] perf_iterate_ctx          -

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20200429150751.12570-8-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3749e0bb

tools/perf/util/intel-pt.c

+66 −7
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ struct intel_pt { 
	bool use_thread_stack;

	bool callstack;

	unsigned int br_stack_sz;

	unsigned int br_stack_sz_plus;

	int have_sched_switch;

	u32 pmu_type;

	u64 kernel_start;
@@ -130,6 +131,7 @@ struct intel_pt { 
	unsigned int range_cnt;



	struct ip_callchain *chain;

	struct branch_stack *br_stack;

};



enum switch_state {
@@ -911,6 +913,44 @@ static void intel_pt_add_callchain(struct intel_pt *pt, 
	sample->callchain = pt->chain;

}



static struct branch_stack *intel_pt_alloc_br_stack(struct intel_pt *pt)

{

	size_t sz = sizeof(struct branch_stack);



	sz += pt->br_stack_sz * sizeof(struct branch_entry);

	return zalloc(sz);

}



static int intel_pt_br_stack_init(struct intel_pt *pt)

{

	struct evsel *evsel;



	evlist__for_each_entry(pt->session->evlist, evsel) {

		if (!(evsel->core.attr.sample_type & PERF_SAMPLE_BRANCH_STACK))

			evsel->synth_sample_type |= PERF_SAMPLE_BRANCH_STACK;

	}



	pt->br_stack = intel_pt_alloc_br_stack(pt);

	if (!pt->br_stack)

		return -ENOMEM;



	return 0;

}



static void intel_pt_add_br_stack(struct intel_pt *pt,

				  struct perf_sample *sample)

{

	struct thread *thread = machine__findnew_thread(pt->machine,

							sample->pid,

							sample->tid);



	thread_stack__br_sample_late(thread, sample->cpu, pt->br_stack,

				     pt->br_stack_sz, sample->ip,

				     pt->kernel_start);



	sample->branch_stack = pt->br_stack;

}



static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,

						   unsigned int queue_nr)

{
@@ -929,10 +969,7 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt, 
	}



	if (pt->synth_opts.last_branch) {

		size_t sz = sizeof(struct branch_stack);



		sz += pt->br_stack_sz * sizeof(struct branch_entry);

		ptq->last_branch = zalloc(sz);

		ptq->last_branch = intel_pt_alloc_br_stack(pt);

		if (!ptq->last_branch)

			goto out_free;

	}
@@ -1963,7 +2000,7 @@ static int intel_pt_sample(struct intel_pt_queue *ptq) 
		thread_stack__event(ptq->thread, ptq->cpu, ptq->flags,

				    state->from_ip, state->to_ip, ptq->insn_len,

				    state->trace_nr, pt->callstack,

				    pt->br_stack_sz,

				    pt->br_stack_sz_plus,

				    pt->mispred_all);

	} else {

		thread_stack__set_trace_nr(ptq->thread, ptq->cpu, state->trace_nr);
@@ -2609,6 +2646,8 @@ static int intel_pt_process_event(struct perf_session *session, 
	if (event->header.type == PERF_RECORD_SAMPLE) {

		if (pt->synth_opts.add_callchain && !sample->callchain)

			intel_pt_add_callchain(pt, sample);

		if (pt->synth_opts.add_last_branch && !sample->branch_stack)

			intel_pt_add_br_stack(pt, sample);

	}



	if (event->header.type == PERF_RECORD_AUX &&
@@ -3370,13 +3409,33 @@ int intel_pt_process_auxtrace_info(union perf_event *event, 
			goto err_delete_thread;

	}



	if (pt->synth_opts.last_branch)

	if (pt->synth_opts.last_branch || pt->synth_opts.add_last_branch) {

		pt->br_stack_sz = pt->synth_opts.last_branch_sz;

		pt->br_stack_sz_plus = pt->br_stack_sz;

	}



	if (pt->synth_opts.add_last_branch) {

		err = intel_pt_br_stack_init(pt);

		if (err)

			goto err_delete_thread;

		/*

		 * Additional branch stack size to cater for tracing from the

		 * actual sample ip to where the sample time is recorded.

		 * Measured at about 200 branches, but generously set to 1024.

		 * If kernel space is not being traced, then add just 1 for the

		 * branch to kernel space.

		 */

		if (intel_pt_tracing_kernel(pt))

			pt->br_stack_sz_plus += 1024;

		else

			pt->br_stack_sz_plus += 1;

	}



	pt->use_thread_stack = pt->synth_opts.callchain ||

			       pt->synth_opts.add_callchain ||

			       pt->synth_opts.thread_stack ||

			       pt->synth_opts.last_branch;

			       pt->synth_opts.last_branch ||

			       pt->synth_opts.add_last_branch;



	pt->callstack = pt->synth_opts.callchain ||

			pt->synth_opts.add_callchain ||

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