[PATCH V3 6/6] tools/perf: Enable perf script to present the DTL entries
Athira Rajeev
atrajeev at linux.ibm.com
Tue Sep 16 15:25:36 AEST 2025
The process_event() function in "builtin-script.c" invokes
perf_sample__fprintf_synth() for displaying PERF_TYPE_SYNTH
type events.
if (attr->type == PERF_TYPE_SYNTH && PRINT_FIELD(SYNTH))
perf_sample__fprintf_synth(sample, evsel, fp);
perf_sample__fprintf_synth() process the sample depending on the value
in evsel->core.attr.config. Introduce perf_sample__fprintf_synth_vpadtl()
and invoke this for PERF_SYNTH_POWERPC_VPA_DTL
Sample output:
./perf record -a -e sched:*,vpa_dtl/dtl_all/ -c 1000000000 sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.300 MB perf.data ]
./perf script
perf 13322 [002] 233.835807: sched:sched_switch: perf:13322 [120] R ==> migration/2:27 [0]
migration/2 27 [002] 233.835811: sched:sched_migrate_task: comm=perf pid=13322 prio=120 orig_cpu=2 dest_cpu=3
migration/2 27 [002] 233.835818: sched:sched_stat_runtime: comm=migration/2 pid=27 runtime=9214 [ns]
migration/2 27 [002] 233.835819: sched:sched_switch: migration/2:27 [0] S ==> swapper/2:0 [120]
swapper 0 [002] 233.835822: vpa-dtl: timebase: 338954486062657 dispatch_reason:decrementer_interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:435, ready_to_enqueue_time:0, waiting_to_ready_time:34775058, processor_id: 202 c0000000000f8094 plpar_hcall_norets_notrace+0x18 ([kernel.kallsyms])
swapper 0 [001] 233.835886: vpa-dtl: timebase: 338954486095398 dispatch_reason:priv_doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:542, ready_to_enqueue_time:0, waiting_to_ready_time:1245360, processor_id: 201 c0000000000f8094 plpar_hcall_norets_notrace+0x18 ([kernel.kallsyms])
Tested-by: Venkat Rao Bagalkote <venkat88 at linux.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev at linux.ibm.com>
---
Changelog:
v3:
Addressed review comments from Adrian
- Remove unnecessary line continuation and line length
- Return number of chars printed for perf_sample__fprintf_synth_vpadtl
- Added Tested by from Venkat
v2:
Addressed review comments from Adrian
- Removed default callback and used perf_sample__fprintf_synth_vpadtl
- fix build failure when using NO_AUXTRACE=1 by
adding code around HAVE_AUXTRACE_SUPPORT
tools/perf/builtin-script.c | 30 ++++++++++++++++++++++++++++++
tools/perf/util/event.h | 3 +++
2 files changed, 33 insertions(+)
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index d9fbdcf72f25..bda5e4914ee7 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -43,6 +43,7 @@
#include <linux/stringify.h>
#include <linux/time64.h>
#include <linux/zalloc.h>
+#include <linux/unaligned.h>
#include <sys/utsname.h>
#include "asm/bug.h"
#include "util/mem-events.h"
@@ -2003,6 +2004,33 @@ static int perf_sample__fprintf_synth_iflag_chg(struct perf_sample *sample, FILE
return len + perf_sample__fprintf_pt_spacing(len, fp);
}
+#ifdef HAVE_AUXTRACE_SUPPORT
+static int perf_sample__fprintf_synth_vpadtl(struct perf_sample *data, FILE *fp)
+{
+ struct powerpc_vpadtl_entry *dtl = (struct powerpc_vpadtl_entry *)data->raw_data;
+ int len;
+
+ len = fprintf(fp, "timebase: %" PRIu64 " dispatch_reason:%s, preempt_reason:%s,\n"
+ "enqueue_to_dispatch_time:%d, ready_to_enqueue_time:%d,"
+ "waiting_to_ready_time:%d, processor_id: %d",
+ get_unaligned_be64(&dtl->timebase),
+ dispatch_reasons[dtl->dispatch_reason],
+ preempt_reasons[dtl->preempt_reason],
+ be32_to_cpu(dtl->enqueue_to_dispatch_time),
+ be32_to_cpu(dtl->ready_to_enqueue_time),
+ be32_to_cpu(dtl->waiting_to_ready_time),
+ be16_to_cpu(dtl->processor_id));
+
+ return len;
+}
+#else
+static int perf_sample__fprintf_synth_vpadtl(struct perf_sample *data __maybe_unused,
+ FILE *fp __maybe_unused)
+{
+ return 0;
+}
+#endif
+
static int perf_sample__fprintf_synth(struct perf_sample *sample,
struct evsel *evsel, FILE *fp)
{
@@ -2025,6 +2053,8 @@ static int perf_sample__fprintf_synth(struct perf_sample *sample,
return perf_sample__fprintf_synth_evt(sample, fp);
case PERF_SYNTH_INTEL_IFLAG_CHG:
return perf_sample__fprintf_synth_iflag_chg(sample, fp);
+ case PERF_SYNTH_POWERPC_VPA_DTL:
+ return perf_sample__fprintf_synth_vpadtl(sample, fp);
default:
break;
}
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 7e0e58979e9c..64c63b59d617 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -271,6 +271,9 @@ struct powerpc_vpadtl_entry {
u64 srr1;
};
+extern const char *dispatch_reasons[11];
+extern const char *preempt_reasons[10];
+
static inline void *perf_synth__raw_data(void *p)
{
return p + 4;
--
2.47.1
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