[PATCH V3 1/3] perf report: Support Retire Latency

kan.liang
2023-02-02T19:22:30Z

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

The Retire Latency field is added in the var3_w of the
PERF_SAMPLE_WEIGHT_STRUCT. The Retire Latency reports pipeline stall
of this instruction compared to the previous instruction in cycles.
That's quite useful to display the information with perf mem report.

The p_stage_cyc for Power is also from the var3_w. Union the p_stage_cyc
and retire_lat to share the code.

Implement X86 specific codes to display the X86 specific header.

Add a new sort key retire_lat for the Retire Latency.

Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---

The kernel patches have been merged. The V3 only includes the perf tool
patches. The V2 can be found at
https://lore.kernel.org/lkml/20230104201349.1451191-1-kan.liang@linux.intel.com/

No change from V2.

tools/perf/Documentation/perf-report.txt | 2 ++
tools/perf/arch/x86/util/event.c | 21 +++++++++++++++++++++
tools/perf/util/sample.h | 5 ++++-
tools/perf/util/sort.c | 2 ++
tools/perf/util/sort.h | 2 ++
5 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 9b0c0dbf9a77..c242e8da6b1a 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -115,6 +115,8 @@ OPTIONS
- p_stage_cyc: On powerpc, this presents the number of cycles spent in a
pipeline stage. And currently supported only on powerpc.
- addr: (Full) virtual address of the sampled instruction
+ - retire_lat: On X86, this reports pipeline stall of this instruction compared
+ to the previous instruction in cycles. And currently supported only on X86

By default, comm, dso and symbol keys are used.
(i.e. --sort comm,dso,symbol)
diff --git a/tools/perf/arch/x86/util/event.c b/tools/perf/arch/x86/util/event.c
index a3acefe6d0c6..e4288d09f3a0 100644
--- a/tools/perf/arch/x86/util/event.c
+++ b/tools/perf/arch/x86/util/event.c
@@ -89,6 +89,7 @@ void arch_perf_parse_sample_weight(struct perf_sample *data,
else {
data->weight = weight.var1_dw;
data->ins_lat = weight.var2_w;
+ data->retire_lat = weight.var3_w;
}
}

@@ -100,5 +101,25 @@ void arch_perf_synthesize_sample_weight(const struct perf_sample *data,
if (type & PERF_SAMPLE_WEIGHT_STRUCT) {
*array &= 0xffffffff;
*array |= ((u64)data->ins_lat << 32);
+ *array |= ((u64)data->retire_lat << 48);
}
}
+
+const char *arch_perf_header_entry(const char *se_header)
+{
+ if (!strcmp(se_header, "Local Pipeline Stage Cycle"))
+ return "Local Retire Latency";
+ else if (!strcmp(se_header, "Pipeline Stage Cycle"))
+ return "Retire Latency";
+
+ return se_header;
+}
+
+int arch_support_sort_key(const char *sort_key)
+{
+ if (!strcmp(sort_key, "p_stage_cyc"))
+ return 1;
+ if (!strcmp(sort_key, "local_p_stage_cyc"))
+ return 1;
+ return 0;
+}
diff --git a/tools/perf/util/sample.h b/tools/perf/util/sample.h
index 60ec79d4eea4..33b08e0ac746 100644
--- a/tools/perf/util/sample.h
+++ b/tools/perf/util/sample.h
@@ -92,7 +92,10 @@ struct perf_sample {
u8 cpumode;
u16 misc;
u16 ins_lat;
- u16 p_stage_cyc;
+ union {
+ u16 p_stage_cyc;
+ u16 retire_lat;
+ };
bool no_hw_idx; /* No hw_idx collected in branch_stack */
char insn[MAX_INSN];
void *raw_data;
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index d7d0f997873a..4a648231fe72 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -2133,6 +2133,8 @@ static struct sort_dimension common_sort_dimensions[] = {
DIM(SORT_LOCAL_PIPELINE_STAGE_CYC, "local_p_stage_cyc", sort_local_p_stage_cyc),
DIM(SORT_GLOBAL_PIPELINE_STAGE_CYC, "p_stage_cyc", sort_global_p_stage_cyc),
DIM(SORT_ADDR, "addr", sort_addr),
+ DIM(SORT_LOCAL_RETIRE_LAT, "local_retire_lat", sort_local_p_stage_cyc),
+ DIM(SORT_GLOBAL_RETIRE_LAT, "retire_lat", sort_global_p_stage_cyc),
};

#undef DIM
diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index 921715e6aec4..9a91d0df2833 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -237,6 +237,8 @@ enum sort_type {
SORT_LOCAL_PIPELINE_STAGE_CYC,
SORT_GLOBAL_PIPELINE_STAGE_CYC,
SORT_ADDR,
+ SORT_LOCAL_RETIRE_LAT,
+ SORT_GLOBAL_RETIRE_LAT,

/* branch stack specific sort keys */
__SORT_BRANCH_STACK,
--
2.35.1