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* [PATCH 1/4] perf, tools: Add support for skipping itrace instructions
@ 2016-03-25 23:02 Andi Kleen
  2016-03-25 23:02 ` [PATCH 2/4] perf, tools: Add probing for udev86 Andi Kleen
                   ` (2 more replies)
  0 siblings, 3 replies; 11+ messages in thread
From: Andi Kleen @ 2016-03-25 23:02 UTC (permalink / raw)
  To: acme; +Cc: jolsa, linux-kernel, Andi Kleen, Adrian Hunter

From: Andi Kleen <ak@linux.intel.com>

When using perf script to look at PT traces it is often
useful to ignore the initialization code at the beginning.

On larger traces which may have many millions of instructions
in initialization code doing that in a pipeline can be very
slow, with perf script spending a lot of CPU time calling
printf and writing data.

This patch adds an extension to the --itrace argument
that skips 'n' events (instructions, branches or transactions)
at the beginning. This is much more efficient.

Cc: Adrian Hunter <adrian.hunter@intel.com>

v2:
Add support for BTS (Adrian Hunter)
Document in itrace.txt
Fix branch check
Check transactions and instructions too
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 tools/perf/Documentation/intel-pt.txt |  7 +++++++
 tools/perf/Documentation/itrace.txt   |  8 ++++++++
 tools/perf/util/auxtrace.c            |  7 +++++++
 tools/perf/util/auxtrace.h            |  2 ++
 tools/perf/util/intel-bts.c           |  5 +++++
 tools/perf/util/intel-pt.c            | 22 ++++++++++++++++++++--
 6 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
index be764f9..c6c8318 100644
--- a/tools/perf/Documentation/intel-pt.txt
+++ b/tools/perf/Documentation/intel-pt.txt
@@ -672,6 +672,7 @@ The letters are:
 	d	create a debug log
 	g	synthesize a call chain (use with i or x)
 	l	synthesize last branch entries (use with i or x)
+	s	skip initial number of events
 
 "Instructions" events look like they were recorded by "perf record -e
 instructions".
@@ -730,6 +731,12 @@ from one sample to the next.
 
 To disable trace decoding entirely, use the option --no-itrace.
 
+It is also possible to skip events generated (instructions, branches, transactions)
+at the beginning. This is useful to ignore initialization code.
+
+	--itrace=i0nss1000000
+
+skips the first million instructions.
 
 dump option
 -----------
diff --git a/tools/perf/Documentation/itrace.txt b/tools/perf/Documentation/itrace.txt
index 65453f4..e2a4c5e 100644
--- a/tools/perf/Documentation/itrace.txt
+++ b/tools/perf/Documentation/itrace.txt
@@ -7,6 +7,7 @@
 		d	create a debug log
 		g	synthesize a call chain (use with i or x)
 		l	synthesize last branch entries (use with i or x)
+		s       skip initial number of events
 
 	The default is all events i.e. the same as --itrace=ibxe
 
@@ -24,3 +25,10 @@
 
 	Also the number of last branch entries (default 64, max. 1024) for
 	instructions or transactions events can be specified.
+
+	It is also possible to skip events generated (instructions, branches, transactions)
+	at the beginning. This is useful to ignore initialization code.
+
+	--itrace=i0nss1000000
+
+	skips the first million instructions.
diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index ec164fe..c916901 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -940,6 +940,7 @@ void itrace_synth_opts__set_default(struct itrace_synth_opts *synth_opts)
 	synth_opts->period = PERF_ITRACE_DEFAULT_PERIOD;
 	synth_opts->callchain_sz = PERF_ITRACE_DEFAULT_CALLCHAIN_SZ;
 	synth_opts->last_branch_sz = PERF_ITRACE_DEFAULT_LAST_BRANCH_SZ;
+	synth_opts->initial_skip = 0;
 }
 
 /*
@@ -1064,6 +1065,12 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 				synth_opts->last_branch_sz = val;
 			}
 			break;
+		case 's':
+			synth_opts->initial_skip = strtoul(p, &endptr, 10);
+			if (p == endptr)
+				goto out_err;
+			p = endptr;
+			break;
 		case ' ':
 		case ',':
 			break;
diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index e5a8e2d..8214292 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -68,6 +68,7 @@ enum itrace_period_type {
  * @last_branch_sz: branch context size
  * @period: 'instructions' events period
  * @period_type: 'instructions' events period type
+ * @initial_skip: skip N events at the beginning.
  */
 struct itrace_synth_opts {
 	bool			set;
@@ -86,6 +87,7 @@ struct itrace_synth_opts {
 	unsigned int		last_branch_sz;
 	unsigned long long	period;
 	enum itrace_period_type	period_type;
+	unsigned long		initial_skip;
 };
 
 /**
diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
index eb0e7f8..e3cc105 100644
--- a/tools/perf/util/intel-bts.c
+++ b/tools/perf/util/intel-bts.c
@@ -66,6 +66,7 @@ struct intel_bts {
 	u64				branches_id;
 	size_t				branches_event_size;
 	bool				synth_needs_swap;
+	unsigned long			num_events;
 };
 
 struct intel_bts_queue {
@@ -275,6 +276,10 @@ static int intel_bts_synth_branch_sample(struct intel_bts_queue *btsq,
 	union perf_event event;
 	struct perf_sample sample = { .ip = 0, };
 
+	if (bts->synth_opts.initial_skip &&
+	    bts->num_events++ <= bts->synth_opts.initial_skip)
+		return 0;
+
 	event.sample.header.type = PERF_RECORD_SAMPLE;
 	event.sample.header.misc = PERF_RECORD_MISC_USER;
 	event.sample.header.size = sizeof(struct perf_event_header);
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 05d8158..07f0020 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -100,6 +100,8 @@ struct intel_pt {
 	u64 cyc_bit;
 	u64 noretcomp_bit;
 	unsigned max_non_turbo_ratio;
+
+	unsigned long num_events;
 };
 
 enum switch_state {
@@ -972,6 +974,10 @@ static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)
 	if (pt->branches_filter && !(pt->branches_filter & ptq->flags))
 		return 0;
 
+	if (pt->synth_opts.initial_skip &&
+	    pt->num_events++ < pt->synth_opts.initial_skip)
+		return 0;
+
 	event->sample.header.type = PERF_RECORD_SAMPLE;
 	event->sample.header.misc = PERF_RECORD_MISC_USER;
 	event->sample.header.size = sizeof(struct perf_event_header);
@@ -1028,6 +1034,10 @@ static int intel_pt_synth_instruction_sample(struct intel_pt_queue *ptq)
 	union perf_event *event = ptq->event_buf;
 	struct perf_sample sample = { .ip = 0, };
 
+	if (pt->synth_opts.initial_skip &&
+	    pt->num_events++ < pt->synth_opts.initial_skip)
+		return 0;
+
 	event->sample.header.type = PERF_RECORD_SAMPLE;
 	event->sample.header.misc = PERF_RECORD_MISC_USER;
 	event->sample.header.size = sizeof(struct perf_event_header);
@@ -1085,6 +1095,10 @@ static int intel_pt_synth_transaction_sample(struct intel_pt_queue *ptq)
 	union perf_event *event = ptq->event_buf;
 	struct perf_sample sample = { .ip = 0, };
 
+	if (pt->synth_opts.initial_skip &&
+	    pt->num_events++ < pt->synth_opts.initial_skip)
+		return 0;
+
 	event->sample.header.type = PERF_RECORD_SAMPLE;
 	event->sample.header.misc = PERF_RECORD_MISC_USER;
 	event->sample.header.size = sizeof(struct perf_event_header);
@@ -1196,14 +1210,18 @@ static int intel_pt_sample(struct intel_pt_queue *ptq)
 	ptq->have_sample = false;
 
 	if (pt->sample_instructions &&
-	    (state->type & INTEL_PT_INSTRUCTION)) {
+	    (state->type & INTEL_PT_INSTRUCTION) &&
+	    (!pt->synth_opts.initial_skip ||
+	     pt->num_events++ >= pt->synth_opts.initial_skip)) {
 		err = intel_pt_synth_instruction_sample(ptq);
 		if (err)
 			return err;
 	}
 
 	if (pt->sample_transactions &&
-	    (state->type & INTEL_PT_TRANSACTION)) {
+	    (state->type & INTEL_PT_TRANSACTION) &&
+	    (!pt->synth_opts.initial_skip ||
+	     pt->num_events++ >= pt->synth_opts.initial_skip)) {
 		err = intel_pt_synth_transaction_sample(ptq);
 		if (err)
 			return err;
-- 
2.5.5

^ permalink raw reply	[flat|nested] 11+ messages in thread
* New attempt at adding an disassembler to perf
@ 2017-01-03  9:00 Andi Kleen
  2017-01-03  9:00 ` [PATCH 4/4] perf, tools, script: Add brstackasm output for branch stacks Andi Kleen
  0 siblings, 1 reply; 11+ messages in thread
From: Andi Kleen @ 2017-01-03  9:00 UTC (permalink / raw)
  To: acme; +Cc: jolsa, mingo, linux-kernel

A native disassembler in perf is very useful, in particular with perf script to trace 
instruction streams, but also for other analysis. Previously I attempted
to do this using the udis86 library, but that was rejected because:
- udis86 was not maintained anymore and lacking recent instructions
- udis86 is dynamically linked and gives a runtime dependency.
Doing this needs a full disassembler, not just a decoder, so the existing
instruction decoder cannot be used without major changes.

This patchkit addresses these issues.  Intel recently released an open source version
of the XED disassembler library, which is used in many other Intel software.
It is very well maintained, uptodate, and supports static linking, so there is no
runtime dependency. This version adds XED support to perf, and uses it to implement
assembler output in perf script. It also fixes a range of issues in the previous
version, see the individual change logs.

Available in 
git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc.git perf/xed-3

v1: First post of XED version

-Andi

^ permalink raw reply	[flat|nested] 11+ messages in thread
end of thread, other threads:[~2017-01-09 19:14 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-03-25 23:02 [PATCH 1/4] perf, tools: Add support for skipping itrace instructions Andi Kleen
2016-03-25 23:02 ` [PATCH 2/4] perf, tools: Add probing for udev86 Andi Kleen
2016-03-27 11:26   ` Jiri Olsa
2016-03-25 23:02 ` [PATCH 3/4] perf, tools, script: Add support for printing assembler Andi Kleen
2016-03-27 11:05   ` Jiri Olsa
2016-03-27 15:35     ` Andi Kleen
2016-03-25 23:02 ` [PATCH 4/4] perf, tools, script: Add brstackasm output for branch stacks Andi Kleen
2017-01-03  9:00 New attempt at adding an disassembler to perf Andi Kleen
2017-01-03  9:00 ` [PATCH 4/4] perf, tools, script: Add brstackasm output for branch stacks Andi Kleen
2017-01-08 14:19   ` Jiri Olsa
2017-01-09 19:14     ` Andi Kleen
2017-01-08 14:20   ` Jiri Olsa

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