[PATCH 11/25] perf intel-pt: Add LBR information to synthesized PEBS sample

Arnaldo Carvalho de Melo
2019-06-21T17:40:14Z

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

Add LBR information from PEBS data in the Intel PT trace to the
synthesized PEBS sample.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190610072803.10456-10-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/intel-pt.c | 72 ++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index f83dd10bb7d0..db00c13dc36f 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -1628,6 +1628,58 @@ static void intel_pt_add_xmm(struct regs_dump *intr_regs, u64 *pos,
}
}

+#define LBR_INFO_MISPRED (1ULL << 63)
+#define LBR_INFO_IN_TX (1ULL << 62)
+#define LBR_INFO_ABORT (1ULL << 61)
+#define LBR_INFO_CYCLES 0xffff
+
+/* Refer kernel's intel_pmu_store_pebs_lbrs() */
+static u64 intel_pt_lbr_flags(u64 info)
+{
+ union {
+ struct branch_flags flags;
+ u64 result;
+ } u = {
+ .flags = {
+ .mispred = !!(info & LBR_INFO_MISPRED),
+ .predicted = !(info & LBR_INFO_MISPRED),
+ .in_tx = !!(info & LBR_INFO_IN_TX),
+ .abort = !!(info & LBR_INFO_ABORT),
+ .cycles = info & LBR_INFO_CYCLES,
+ }
+ };
+
+ return u.result;
+}
+
+static void intel_pt_add_lbrs(struct branch_stack *br_stack,
+ const struct intel_pt_blk_items *items)
+{
+ u64 *to;
+ int i;
+
+ br_stack->nr = 0;
+
+ to = &br_stack->entries[0].from;
+
+ for (i = INTEL_PT_LBR_0_POS; i <= INTEL_PT_LBR_2_POS; i++) {
+ u32 mask = items->mask[i];
+ const u64 *from = items->val[i];
+
+ for (; mask; mask >>= 3, from += 3) {
+ if ((mask & 7) == 7) {
+ *to++ = from[0];
+ *to++ = from[1];
+ *to++ = intel_pt_lbr_flags(from[2]);
+ br_stack->nr += 1;
+ }
+ }
+ }
+}
+
+/* INTEL_PT_LBR_0, INTEL_PT_LBR_1 and INTEL_PT_LBR_2 */
+#define LBRS_MAX (INTEL_PT_BLK_ITEM_ID_CNT * 3)
+
static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
{
const struct intel_pt_blk_items *items = &ptq->state->items;
@@ -1694,6 +1746,26 @@ static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
intel_pt_add_xmm(&sample.intr_regs, pos, items, regs_mask);
}

+ if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
+ struct {
+ struct branch_stack br_stack;
+ struct branch_entry entries[LBRS_MAX];
+ } br;
+
+ if (items->mask[INTEL_PT_LBR_0_POS] ||
+ items->mask[INTEL_PT_LBR_1_POS] ||
+ items->mask[INTEL_PT_LBR_2_POS]) {
+ intel_pt_add_lbrs(&br.br_stack, items);
+ sample.branch_stack = &br.br_stack;
+ } else if (pt->synth_opts.last_branch) {
+ intel_pt_copy_last_branch_rb(ptq);
+ sample.branch_stack = ptq->last_branch;
+ } else {
+ br.br_stack.nr = 0;
+ sample.branch_stack = &br.br_stack;
+ }
+ }
+
return intel_pt_deliver_synth_event(pt, ptq, event, &sample, sample_type);
}

--
2.20.1