From: kan.liang@linux.intel.com
To: peterz@infradead.org, acme@redhat.com, mingo@kernel.org,
linux-kernel@vger.kernel.org
Cc: jolsa@kernel.org, namhyung@kernel.org,
vitaly.slobodskoy@intel.com, pavel.gerasimov@intel.com,
ak@linux.intel.com, eranian@google.com, mpe@ellerman.id.au,
Kan Liang <kan.liang@linux.intel.com>
Subject: [PATCH V4 09/13] perf report: Add option to enable the LBR stitching approach
Date: Tue, 19 Nov 2019 06:34:07 -0800 [thread overview]
Message-ID: <20191119143411.3482-10-kan.liang@linux.intel.com> (raw)
In-Reply-To: <20191119143411.3482-1-kan.liang@linux.intel.com>
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.
# To display the perf.data header info, please use
# --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 6K of event 'cycles'
# Event count (approx.): 6492797701
#
# Children Self Command Shared Object Symbol
# ........ ........ ............... ..................
# .................................
#
99.99% 99.99% tchain_edit tchain_edit [.] f43
|
---main
f1
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|
--99.65%--f32
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Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
tools/perf/Documentation/perf-report.txt | 11 +++++++++++
tools/perf/builtin-report.c | 6 ++++++
2 files changed, 17 insertions(+)
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 8dbe2119686a..b42bd38e5790 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -476,6 +476,17 @@ include::itrace.txt[]
This option extends the perf report to show reference callgraphs,
which collected by reference event, in no callgraph event.
+--stitch-lbr::
+ Show callgraph with stitched LBRs, which may have more complete
+ callgraph. The perf.data file must have been obtained using
+ perf record --call-graph lbr.
+ 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.
+
--socket-filter::
Only report the samples on the processor socket that match with this filter
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 585805f51f15..00c1d8a47b18 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -84,6 +84,7 @@ struct report {
bool header_only;
bool nonany_branch_mode;
bool group_set;
+ bool stitch_lbr;
int max_stack;
struct perf_read_values show_threads_values;
struct annotation_options annotation_opts;
@@ -267,6 +268,9 @@ static int process_sample_event(struct perf_tool *tool,
return -1;
}
+ if (rep->stitch_lbr)
+ al.thread->lbr_stitch_enable = true;
+
if (symbol_conf.hide_unresolved && al.sym == NULL)
goto out_put;
@@ -1229,6 +1233,8 @@ int cmd_report(int argc, const char **argv)
"Show full source file name path for source lines"),
OPT_BOOLEAN(0, "show-ref-call-graph", &symbol_conf.show_ref_callgraph,
"Show callgraph from reference event"),
+ OPT_BOOLEAN(0, "stitch-lbr", &report.stitch_lbr,
+ "Enable LBR callgraph stitching approach"),
OPT_INTEGER(0, "socket-filter", &report.socket_filter,
"only show processor socket that match with this filter"),
OPT_BOOLEAN(0, "raw-trace", &symbol_conf.raw_trace,
--
2.17.1
next prev parent reply other threads:[~2019-11-19 14:35 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-19 14:33 [PATCH V4 00/13] Stitch LBR call stack kan.liang
2019-11-19 14:33 ` [PATCH V4 01/13] perf/core: Add new branch sample type for LBR TOS kan.liang
2019-11-19 19:02 ` Stephane Eranian
2019-11-19 22:25 ` Liang, Kan
2019-11-19 22:51 ` Stephane Eranian
2019-11-20 15:06 ` Liang, Kan
2019-11-19 14:34 ` [PATCH V4 02/13] perf/x86/intel: Output LBR TOS information kan.liang
2019-11-19 14:34 ` [PATCH V4 03/13] perf tools: Support new branch sample type for LBR TOS kan.liang
2019-11-19 19:00 ` Stephane Eranian
2019-11-19 21:31 ` Peter Zijlstra
2019-11-19 22:17 ` Liang, Kan
2019-11-19 14:34 ` [PATCH V4 04/13] perf header: Add check for event attr kan.liang
2019-11-19 14:34 ` [PATCH V4 05/13] perf pmu: Add support for PMU capabilities kan.liang
2019-11-19 14:34 ` [PATCH V4 06/13] perf header: Support CPU " kan.liang
2019-11-19 14:34 ` [PATCH V4 07/13] perf machine: Refine the function for LBR call stack reconstruction kan.liang
2019-11-19 14:34 ` [PATCH V4 08/13] perf tools: Stitch LBR call stack kan.liang
2019-11-19 14:34 ` kan.liang [this message]
2019-11-19 14:34 ` [PATCH V4 10/13] perf script: Add option to enable the LBR stitching approach kan.liang
2019-11-19 14:34 ` [PATCH V4 11/13] perf top: " kan.liang
2019-11-19 14:34 ` [PATCH V4 12/13] perf c2c: " kan.liang
2019-11-19 14:34 ` [RFC PATCH V4 13/13] perf hist: Add fast path for duplicate entries check approach kan.liang
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