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[PATCH 1/2] perf intel-pt-decoder: Report instruction bytes and length in sample

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  [PATCH 1/2] perf intel-pt-decoder: Report instruction bytes and length in sample Andi Kleen <andi@firstfloor.org> - 2016-09-30 06:00 +0200
    Re: [PATCH 1/2] perf intel-pt-decoder: Report instruction bytes and  length in sample Adrian Hunter <adrian.hunter@intel.com> - 2016-09-30 12:20 +0200
      Re: [PATCH 1/2] perf intel-pt-decoder: Report instruction bytes and  length in sample Andi Kleen <andi@firstfloor.org> - 2016-10-04 02:40 +0200

#1493878 — [PATCH 1/2] perf intel-pt-decoder: Report instruction bytes and length in sample

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

Change the Intel PT decoder to pass up the length and the instruction
bytes of the decoded or sampled instruction in the perf sample.

The decoder already knows this information, we just need to pass it
up. Since it is only a couple of movs it is not very expensive.

Used in the next patch.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 tools/perf/util/event.h                                  | 3 +++
 tools/perf/util/intel-pt-decoder/intel-pt-decoder.c      | 2 ++
 tools/perf/util/intel-pt-decoder/intel-pt-decoder.h      | 3 +++
 tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h | 2 +-
 tools/perf/util/intel-pt.c                               | 5 +++++
 5 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 8d363d5e65a2..c735c53a26f8 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -177,6 +177,8 @@ enum {
 	PERF_IP_FLAG_TRACE_BEGIN	|\
 	PERF_IP_FLAG_TRACE_END)
 
+#define MAX_INSN 16
+
 struct perf_sample {
 	u64 ip;
 	u32 pid, tid;
@@ -193,6 +195,7 @@ struct perf_sample {
 	u32 flags;
 	u16 insn_len;
 	u8  cpumode;
+	char insn[MAX_INSN];
 	void *raw_data;
 	struct ip_callchain *callchain;
 	struct branch_stack *branch_stack;
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index 8ff6c6a61291..8a5e21abb790 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -949,6 +949,8 @@ out:
 out_no_progress:
 	decoder->state.insn_op = intel_pt_insn->op;
 	decoder->state.insn_len = intel_pt_insn->length;
+	memcpy(decoder->state.insn, intel_pt_insn->buf,
+	       sizeof(decoder->state.insn));
 
 	if (decoder->tx_flags & INTEL_PT_IN_TX)
 		decoder->state.flags |= INTEL_PT_IN_TX;
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
index 02c38fec1c37..fbd7d08d97d5 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
@@ -20,6 +20,8 @@
 #include <stddef.h>
 #include <stdbool.h>
 
+#define MAX_INSN			16
+
 #include "intel-pt-insn-decoder.h"
 
 #define INTEL_PT_IN_TX		(1 << 0)
@@ -66,6 +68,7 @@ struct intel_pt_state {
 	uint32_t flags;
 	enum intel_pt_insn_op insn_op;
 	int insn_len;
+	char insn[MAX_INSN];
 };
 
 struct intel_pt_insn;
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h
index b0adbf37323e..47e196dec224 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h
@@ -20,7 +20,7 @@
 #include <stdint.h>
 
 #define INTEL_PT_INSN_DESC_MAX		32
-#define INTEL_PT_INSN_DBG_BUF_SZ	16
+#define INTEL_PT_INSN_DBG_BUF_SZ	16 /* Must be >= MAX_INSN */
 
 enum intel_pt_insn_op {
 	INTEL_PT_OP_OTHER,
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index b9cc353cace2..363eba09c609 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -140,6 +140,7 @@ struct intel_pt_queue {
 	u32 flags;
 	u16 insn_len;
 	u64 last_insn_cnt;
+	char insn[MAX_INSN];
 };
 
 static void intel_pt_dump(struct intel_pt *pt __maybe_unused,
@@ -817,6 +818,7 @@ static void intel_pt_sample_flags(struct intel_pt_queue *ptq)
 		if (ptq->state->flags & INTEL_PT_IN_TX)
 			ptq->flags |= PERF_IP_FLAG_IN_TX;
 		ptq->insn_len = ptq->state->insn_len;
+		memcpy(ptq->insn, ptq->state->insn, MAX_INSN);
 	}
 }
 
@@ -997,6 +999,7 @@ static int intel_pt_synth_branch_sample(struct intel_pt_queue *ptq)
 	sample.cpu = ptq->cpu;
 	sample.flags = ptq->flags;
 	sample.insn_len = ptq->insn_len;
+	memcpy(sample.insn, ptq->insn, MAX_INSN);
 
 	/*
 	 * perf report cannot handle events without a branch stack when using
@@ -1058,6 +1061,7 @@ static int intel_pt_synth_instruction_sample(struct intel_pt_queue *ptq)
 	sample.cpu = ptq->cpu;
 	sample.flags = ptq->flags;
 	sample.insn_len = ptq->insn_len;
+	memcpy(sample.insn, ptq->insn, MAX_INSN);
 
 	ptq->last_insn_cnt = ptq->state->tot_insn_cnt;
 
@@ -1120,6 +1124,7 @@ static int intel_pt_synth_transaction_sample(struct intel_pt_queue *ptq)
 	sample.cpu = ptq->cpu;
 	sample.flags = ptq->flags;
 	sample.insn_len = ptq->insn_len;
+	memcpy(sample.insn, ptq->insn, MAX_INSN);
 
 	if (pt->synth_opts.callchain) {
 		thread_stack__sample(ptq->thread, ptq->chain,
-- 
2.5.5

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#1494015 — Re: [PATCH 1/2] perf intel-pt-decoder: Report instruction bytes and length in sample

On 30/09/16 06:49, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> Change the Intel PT decoder to pass up the length and the instruction
> bytes of the decoded or sampled instruction in the perf sample.
> 
> The decoder already knows this information, we just need to pass it
> up. Since it is only a couple of movs it is not very expensive.

The decoder doesn't always fill the instruction buffer because it caches the
results from walking basic blocks.  That means the bytes from the last
instruction in the basic block would need to be added to the cache.

I wonder if we shouldn't look at something more sophisticated e.g. a python
script that can do full disassembly.

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#1495121 — Re: [PATCH 1/2] perf intel-pt-decoder: Report instruction bytes and length in sample

On Fri, Sep 30, 2016 at 01:07:17PM +0300, Adrian Hunter wrote:
> On 30/09/16 06:49, Andi Kleen wrote:
> > From: Andi Kleen <ak@linux.intel.com>
> > 
> > Change the Intel PT decoder to pass up the length and the instruction
> > bytes of the decoded or sampled instruction in the perf sample.
> > 
> > The decoder already knows this information, we just need to pass it
> > up. Since it is only a couple of movs it is not very expensive.
> 
> The decoder doesn't always fill the instruction buffer because it caches the
> results from walking basic blocks.  That means the bytes from the last
> instruction in the basic block would need to be added to the cache.

I fixed this and posted a new version.
> 
> I wonder if we shouldn't look at something more sophisticated e.g. a python
> script that can do full disassembly.

I had an earlier version that used a disassembler library, but that
wasn't appreciated, so now switched to this simpler method.
Assembler output can be done with a sed + objdump hack now.

-Andi

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