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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Clark Williams <williams@redhat.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	Kan Liang <kan.liang@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>, Jiri Olsa <jolsa@redhat.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Alexey Budankov <alexey.budankov@linux.intel.com>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Pavel Gerasimov <pavel.gerasimov@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
	Stephane Eranian <eranian@google.com>,
	Vitaly Slobodskoy <vitaly.slobodskoy@intel.com>
Subject: [PATCH 58/60] perf top: Add option to enable the LBR stitching approach
Date: Mon, 20 Apr 2020 08:53:14 -0300	[thread overview]
Message-ID: <20200420115316.18781-59-acme@kernel.org> (raw)
In-Reply-To: <20200420115316.18781-1-acme@kernel.org>

From: Kan Liang <kan.liang@linux.intel.com>

With the LBR stitching approach, the reconstructed LBR call stack
can break the HW limitation. However, it may reconstruct invalid call
stacks in some cases, e.g. exception handing such as setjmp/longjmp.
Also, it may impact the processing time especially when the number of
samples with stitched LBRs are huge.

Add an option to enable the approach.
The option must be used with --call-graph lbr.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Pavel Gerasimov <pavel.gerasimov@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com>
Link: http://lore.kernel.org/lkml/20200319202517.23423-16-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-top.txt |  9 +++++++++
 tools/perf/builtin-top.c              | 11 +++++++++++
 tools/perf/util/top.h                 |  1 +
 3 files changed, 21 insertions(+)

diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt
index 487737a725e9..20227dabc208 100644
--- a/tools/perf/Documentation/perf-top.txt
+++ b/tools/perf/Documentation/perf-top.txt
@@ -319,6 +319,15 @@ Default is to monitor all CPUS.
 	go straight to the histogram browser, just like 'perf top' with no events
 	explicitely specified does.
 
+--stitch-lbr::
+	Show callgraph with stitched LBRs, which may have more complete
+	callgraph. The option must be used with --call-graph lbr recording.
+	Disabled by default. In common cases with call stack overflows,
+	it can recreate better call stacks than the default lbr call stack
+	output. But this approach is not full proof. There can be cases
+	where it creates incorrect call stacks from incorrect matches.
+	The known limitations include exception handing such as
+	setjmp/longjmp will have calls/returns not match.
 
 INTERACTIVE PROMPTING KEYS
 --------------------------
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 289cf83e658a..6b067a5ba1d5 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -33,6 +33,7 @@
 #include "util/map.h"
 #include "util/mmap.h"
 #include "util/session.h"
+#include "util/thread.h"
 #include "util/symbol.h"
 #include "util/synthetic-events.h"
 #include "util/top.h"
@@ -775,6 +776,9 @@ static void perf_event__process_sample(struct perf_tool *tool,
 	if (machine__resolve(machine, &al, sample) < 0)
 		return;
 
+	if (top->stitch_lbr)
+		al.thread->lbr_stitch_enable = true;
+
 	if (!machine->kptr_restrict_warned &&
 	    symbol_conf.kptr_restrict &&
 	    al.cpumode == PERF_RECORD_MISC_KERNEL) {
@@ -1571,6 +1575,8 @@ int cmd_top(int argc, const char **argv)
 		    "Sort the output by the event at the index n in group. "
 		    "If n is invalid, sort by the first event. "
 		    "WARNING: should be used on grouped events."),
+	OPT_BOOLEAN(0, "stitch-lbr", &top.stitch_lbr,
+		    "Enable LBR callgraph stitching approach"),
 	OPTS_EVSWITCH(&top.evswitch),
 	OPT_END()
 	};
@@ -1640,6 +1646,11 @@ int cmd_top(int argc, const char **argv)
 		}
 	}
 
+	if (top.stitch_lbr && !(callchain_param.record_mode == CALLCHAIN_LBR)) {
+		pr_err("Error: --stitch-lbr must be used with --call-graph lbr\n");
+		goto out_delete_evlist;
+	}
+
 	if (opts->branch_stack && callchain_param.enabled)
 		symbol_conf.show_branchflag_count = true;
 
diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h
index f117d4f4821e..45dc84ddff37 100644
--- a/tools/perf/util/top.h
+++ b/tools/perf/util/top.h
@@ -36,6 +36,7 @@ struct perf_top {
 	bool		   use_tui, use_stdio;
 	bool		   vmlinux_warned;
 	bool		   dump_symtab;
+	bool		   stitch_lbr;
 	struct hist_entry  *sym_filter_entry;
 	struct evsel 	   *sym_evsel;
 	struct perf_session *session;
-- 
2.21.1


  parent reply	other threads:[~2020-04-20 11:57 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-20 11:52 [GIT PULL] perf/core improvements and fixes Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 01/60] perf stat: Honour --timeout for forked workloads Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 02/60] perf tools: Synthesize bpf_trampoline/dispatcher ksymbol event Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 03/60] perf machine: Set ksymbol dso as loaded on arrival Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 04/60] perf annotate: Add basic support for bpf_image Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 05/60] capabilities: Introduce CAP_PERFMON to kernel and user space Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 06/60] perf/core: Open access to the core for CAP_PERFMON privileged process Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 07/60] perf/core: open access to probes " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 08/60] perf tools: Support CAP_PERFMON capability Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 09/60] drm/i915/perf: Open access for CAP_PERFMON privileged process Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 10/60] trace/bpf_trace: " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 11/60] powerpc/perf: open " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 12/60] parisc/perf: " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 13/60] drivers/perf: Open " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 14/60] drivers/oprofile: " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 15/60] doc/admin-guide: Update perf-security.rst with CAP_PERFMON information Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 16/60] doc/admin-guide: update kernel.rst " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 17/60] perf script: Simplify auxiliary event printing functions Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 18/60] perf bench: Add event synthesis benchmark Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 19/60] tools api fs: Make xxx__mountpoint() more scalable Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 20/60] perf synthetic-events: save 4kb from 2 stack frames Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 21/60] perf expr: Add expr_ prefix for parse_ctx and parse_id Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 22/60] perf expr: Add expr_scanner_ctx object Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 23/60] perf metrictroup: Split the metricgroup__add_metric function Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 24/60] perf script: Add flamegraph.py script Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 25/60] perf auxtrace: Add ->evsel_is_auxtrace() callback Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 26/60] perf intel-pt: Implement " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 27/60] perf intel-bts: " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 28/60] perf arm-spe: " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 29/60] perf cs-etm: " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 30/60] perf s390-cpumsf: " Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 31/60] perf auxtrace: For reporting purposes, un-group AUX area event Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 32/60] perf auxtrace: Add an option to synthesize callchains for regular events Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 33/60] perf thread-stack: Add thread_stack__sample_late() Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 34/60] perf evsel: Be consistent when looking which evsel PERF_SAMPLE_ bits are set Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 35/60] perf evsel: Add support for synthesized sample type Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 36/60] perf intel-pt: Add support for synthesizing callchains for regular events Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 37/60] perf evsel: Move and globalize perf_evsel__find_pmu() and perf_evsel__is_aux_event() Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 38/60] perf evlist: Move leader-sampling configuration Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 39/60] perf evsel: Rearrange perf_evsel__config_leader_sampling() Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 40/60] perf evlist: Allow multiple read formats Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 41/60] perf tools: Add support for leader-sampling with AUX area events Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 42/60] perf stat: Force error in fallback on :k events Arnaldo Carvalho de Melo
2020-04-20 11:52 ` [PATCH 43/60] tools lib traceevent: Take care of return value of asprintf Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 44/60] perf pmu: Add support for PMU capabilities Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 45/60] perf doc: allow ASCIIDOC_EXTRA to be an argument Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 46/60] perf parser: Add support to specify rXXX event with pmu Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 47/60] perf header: Support CPU PMU capabilities Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 48/60] perf machine: Remove the indent in resolve_lbr_callchain_sample Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 49/60] perf machine: Refine the function for LBR call stack reconstruction Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 50/60] perf machine: Factor out lbr_callchain_add_kernel_ip() Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 51/60] perf machine: Factor out lbr_callchain_add_lbr_ip() Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 52/60] perf thread: Add a knob for LBR stitch approach Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 53/60] perf thread: Save previous sample for LBR stitching approach Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 54/60] perf callchain: Save previous cursor nodes " Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 55/60] perf callchain: Stitch LBR call stack Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 56/60] perf report: Add option to enable the LBR stitching approach Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 57/60] perf script: " Arnaldo Carvalho de Melo
2020-04-20 11:53 ` Arnaldo Carvalho de Melo [this message]
2020-04-20 11:53 ` [PATCH 59/60] perf c2c: " Arnaldo Carvalho de Melo
2020-04-20 11:53 ` [PATCH 60/60] perf hist: Add fast path for duplicate entries check Arnaldo Carvalho de Melo
2020-04-22 12:09 ` [GIT PULL] perf/core improvements and fixes Ingo Molnar
2020-04-23 21:28   ` Daniel Díaz
2020-04-24 13:07     ` Arnaldo Carvalho de Melo
2020-04-24 14:10       ` Andreas Gerstmayr
2020-05-04 19:07         ` Daniel Díaz
2020-05-05 16:37           ` Arnaldo Carvalho de Melo
2020-05-05 16:57             ` Daniel Díaz
2020-05-05 17:03               ` Arnaldo Carvalho de Melo
2020-05-08 13:04     ` [tip: perf/core] perf flamegraph: Use /bin/bash for report and record scripts tip-bot2 for Arnaldo Carvalho de Melo

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