[PATCH 08/14] tools/perf: process auxtrace events and display in perf report -D

Athira Rajeev atrajeev at linux.ibm.com
Fri Aug 15 18:34:01 AEST 2025


Add vpa dtl pmu auxtrace process function for "perf report -D".
The auxtrace event processing functions are defined in file
"util/powerpc-vpadtl.c". Data structures used includes "struct
powerpc_vpadtl_queue", "struct powerpc_vpadtl" to store the auxtrace
buffers in queue. Different PERF_RECORD_XXX are generated
during recording. PERF_RECORD_AUXTRACE_INFO is processed first
since it is of type perf_user_event_type and perf session event
delivers perf_session__process_user_event() first. Define function
powerpc_vpadtl_process_auxtrace_info() to handle the processing of
PERF_RECORD_AUXTRACE_INFO records. In this function, initialize
the aux buffer queues using auxtrace_queues__init(). Setup the
required infrastructure for aux data processing. The data is collected
per CPU and auxtrace_queue is created for each CPU.

Define powerpc_vpadtl_process_event() function to process
PERF_RECORD_AUXTRACE records. In this, add the event to queue using
auxtrace_queues__add_event() and process the buffer in
powerpc_vpadtl_dump_event(). The first entry in the buffer with
timebase as zero has boot timebase and frequency. Remaining data is of
format for "struct dtl_entry". Define the translation for
dispatch_reasons and preempt_reasons, report this when dump trace is
invoked via powerpc_vpadtl_dump()

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 report -D

   0 0 0x39b10 [0x30]: PERF_RECORD_AUXTRACE size: 0x690  offset: 0  ref: 0  idx: 0  tid: -1  cpu: 0
   .
   . ... VPA DTL PMU data: size 1680 bytes, entries is 35
   .  00000000: boot_tb: 21349649546353231, tb_freq: 512000000
   .  00000030: dispatch_reason:decrementer interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:7064, ready_to_enqueue_time:187, waiting_to_ready_time:6611773
   .  00000060: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:146, ready_to_enqueue_time:0, waiting_to_ready_time:15359437
   .  00000090: dispatch_reason:decrementer interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:4868, ready_to_enqueue_time:232, waiting_to_ready_time:5100709
   .  000000c0: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:179, ready_to_enqueue_time:0, waiting_to_ready_time:30714243
   .  000000f0: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:197, ready_to_enqueue_time:0, waiting_to_ready_time:15350648
   .  00000120: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:213, ready_to_enqueue_time:0, waiting_to_ready_time:15353446
   .  00000150: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:212, ready_to_enqueue_time:0, waiting_to_ready_time:15355126
   .  00000180: dispatch_reason:decrementer interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:6368, ready_to_enqueue_time:164, waiting_to_ready_time:5104665

Signed-off-by: Athira Rajeev <atrajeev at linux.ibm.com>
---
 tools/perf/util/Build            |   1 +
 tools/perf/util/auxtrace.c       |   2 +
 tools/perf/util/powerpc-vpadtl.c | 299 +++++++++++++++++++++++++++++++
 3 files changed, 302 insertions(+)
 create mode 100644 tools/perf/util/powerpc-vpadtl.c

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 4959e7a990e4..5ead46dc98e7 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -136,6 +136,7 @@ perf-util-$(CONFIG_AUXTRACE) += arm-spe-decoder/
 perf-util-$(CONFIG_AUXTRACE) += hisi-ptt.o
 perf-util-$(CONFIG_AUXTRACE) += hisi-ptt-decoder/
 perf-util-$(CONFIG_AUXTRACE) += s390-cpumsf.o
+perf-util-$(CONFIG_AUXTRACE) += powerpc-vpadtl.o
 
 ifdef CONFIG_LIBOPENCSD
 perf-util-$(CONFIG_AUXTRACE) += cs-etm.o
diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index f587d386c5ef..bd1404f26bb7 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -1395,6 +1395,8 @@ int perf_event__process_auxtrace_info(struct perf_session *session,
 		err = hisi_ptt_process_auxtrace_info(event, session);
 		break;
 	case PERF_AUXTRACE_VPA_PMU:
+		err = powerpc_vpadtl_process_auxtrace_info(event, session);
+		break;
 	case PERF_AUXTRACE_UNKNOWN:
 	default:
 		return -EINVAL;
diff --git a/tools/perf/util/powerpc-vpadtl.c b/tools/perf/util/powerpc-vpadtl.c
new file mode 100644
index 000000000000..ea7b59c45f4a
--- /dev/null
+++ b/tools/perf/util/powerpc-vpadtl.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VPA DTL PMU support
+ */
+
+#include <endian.h>
+#include <errno.h>
+#include <byteswap.h>
+#include <inttypes.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <linux/log2.h>
+#include <elf.h>
+#include <limits.h>
+
+#include "cpumap.h"
+#include "color.h"
+#include "evsel.h"
+#include "evlist.h"
+#include "machine.h"
+#include "session.h"
+#include "util.h"
+#include "thread.h"
+#include "debug.h"
+#include "auxtrace.h"
+#include "powerpc-vpadtl.h"
+#include "map.h"
+#include "symbol_conf.h"
+#include "symbol.h"
+
+/*
+ * The DTL entries are of below format
+ */
+struct dtl_entry {
+	u8      dispatch_reason;
+	u8      preempt_reason;
+	u16     processor_id;
+	u32     enqueue_to_dispatch_time;
+	u32     ready_to_enqueue_time;
+	u32     waiting_to_ready_time;
+	u64     timebase;
+	u64     fault_addr;
+	u64     srr0;
+	u64     srr1;
+};
+
+/*
+ * Structure to save the auxtrace queue
+ */
+struct powerpc_vpadtl {
+	struct auxtrace			auxtrace;
+	struct auxtrace_queues		queues;
+	struct auxtrace_heap		heap;
+	u32				auxtrace_type;
+	struct perf_session		*session;
+	struct machine			*machine;
+	u32				pmu_type;
+};
+
+struct boottb_freq {
+	u64     boot_tb;
+	u64     tb_freq;
+	u64     timebase;
+	u64     padded[3];
+};
+
+struct powerpc_vpadtl_queue {
+	struct powerpc_vpadtl	*vpa;
+	unsigned int		queue_nr;
+	struct auxtrace_buffer	*buffer;
+	struct thread		*thread;
+	bool			on_heap;
+	bool			done;
+	pid_t			pid;
+	pid_t			tid;
+	int			cpu;
+};
+
+const char *dispatch_reasons[11] = {
+	"external_interrupt",
+	"firmware_internal_event",
+	"H_PROD",
+	"decrementer_interrupt",
+	"system_reset",
+	"firmware_internal_event",
+	"conferred_cycles",
+	"time_slice",
+	"virtual_memory_page_fault",
+	"expropriated_adjunct",
+	"priv_doorbell"};
+
+const char *preempt_reasons[10] = {
+	"unused",
+	"firmware_internal_event",
+	"H_CEDE",
+	"H_CONFER",
+	"time_slice",
+	"migration_hibernation_page_fault",
+	"virtual_memory_page_fault",
+	"H_CONFER_ADJUNCT",
+	"hcall_adjunct",
+	"HDEC_adjunct"};
+
+#define	dtl_entry_size	48
+
+/*
+ * Function to dump the dispatch trace data when perf report
+ * is invoked with -D
+ */
+static void powerpc_vpadtl_dump(struct powerpc_vpadtl *vpa __maybe_unused,
+			 unsigned char *buf, size_t len)
+{
+	struct dtl_entry *dtl;
+	int pkt_len, pos = 0;
+	const char *color = PERF_COLOR_BLUE;
+
+	color_fprintf(stdout, color,
+			". ... VPA DTL PMU data: size %zu bytes, entries is %zu\n",
+			len, len/dtl_entry_size);
+
+	if (len % dtl_entry_size)
+		len = len - (len % dtl_entry_size);
+
+	while (len) {
+		pkt_len = 48;
+		printf(".");
+		color_fprintf(stdout, color, "  %08x: ", pos);
+		dtl = (struct dtl_entry *)buf;
+		if (dtl->timebase != 0) {
+			printf("dispatch_reason:%s, preempt_reason:%s, enqueue_to_dispatch_time:%d, ready_to_enqueue_time:%d, waiting_to_ready_time:%d\n",
+					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));
+		} else {
+			struct boottb_freq *boot_tb = (struct boottb_freq *)buf;
+
+			printf("boot_tb: %" PRIu64 ", tb_freq: %" PRIu64 "\n", boot_tb->boot_tb, boot_tb->tb_freq);
+		}
+
+		pos += pkt_len;
+		buf += pkt_len;
+		len -= pkt_len;
+	}
+}
+
+static void powerpc_vpadtl_dump_event(struct powerpc_vpadtl *vpa, unsigned char *buf,
+			       size_t len)
+{
+	printf(".\n");
+	powerpc_vpadtl_dump(vpa, buf, len);
+}
+
+static int powerpc_vpadtl_process_event(struct perf_session *session __maybe_unused,
+				 union perf_event *event __maybe_unused,
+				 struct perf_sample *sample __maybe_unused,
+				 const struct perf_tool *tool __maybe_unused)
+{
+	return 0;
+}
+
+/*
+ * Process PERF_RECORD_AUXTRACE records
+ */
+static int powerpc_vpadtl_process_auxtrace_event(struct perf_session *session,
+					  union perf_event *event,
+					  const struct perf_tool *tool __maybe_unused)
+{
+	struct powerpc_vpadtl *vpa = container_of(session->auxtrace, struct powerpc_vpadtl,
+					     auxtrace);
+	struct auxtrace_buffer *buffer;
+	off_t data_offset;
+	int fd = perf_data__fd(session->data);
+	int err;
+
+	if (perf_data__is_pipe(session->data)) {
+		data_offset = 0;
+	} else {
+		data_offset = lseek(fd, 0, SEEK_CUR);
+		if (data_offset == -1)
+			return -errno;
+	}
+
+	err = auxtrace_queues__add_event(&vpa->queues, session, event,
+					 data_offset, &buffer);
+	if (err)
+		return err;
+
+	/* Dump here now we have copied a piped trace out of the pipe */
+	if (dump_trace) {
+		if (auxtrace_buffer__get_data(buffer, fd)) {
+			powerpc_vpadtl_dump_event(vpa, buffer->data,
+					     buffer->size);
+			auxtrace_buffer__put_data(buffer);
+		}
+	}
+
+	return 0;
+}
+
+static int powerpc_vpadtl_flush(struct perf_session *session __maybe_unused,
+			 const struct perf_tool *tool __maybe_unused)
+{
+	return 0;
+}
+
+static void powerpc_vpadtl_free_queue(void *priv)
+{
+	struct powerpc_vpadtl_queue *vpaq = priv;
+
+	if (!vpaq)
+		return;
+
+	free(vpaq);
+}
+
+static void powerpc_vpadtl_free_events(struct perf_session *session)
+{
+	struct powerpc_vpadtl *vpa = container_of(session->auxtrace, struct powerpc_vpadtl,
+					     auxtrace);
+	struct auxtrace_queues *queues = &vpa->queues;
+	unsigned int i;
+
+	for (i = 0; i < queues->nr_queues; i++) {
+		powerpc_vpadtl_free_queue(queues->queue_array[i].priv);
+		queues->queue_array[i].priv = NULL;
+	}
+	auxtrace_queues__free(queues);
+}
+
+static void powerpc_vpadtl_free(struct perf_session *session)
+{
+	struct powerpc_vpadtl *vpa = container_of(session->auxtrace, struct powerpc_vpadtl,
+					     auxtrace);
+
+	auxtrace_heap__free(&vpa->heap);
+	powerpc_vpadtl_free_events(session);
+	session->auxtrace = NULL;
+	free(vpa);
+}
+
+static const char * const powerpc_vpadtl_info_fmts[] = {
+	[POWERPC_VPADTL_TYPE]		= "  PMU Type           %"PRId64"\n",
+};
+
+static void powerpc_vpadtl_print_info(__u64 *arr)
+{
+	if (!dump_trace)
+		return;
+
+	fprintf(stdout, powerpc_vpadtl_info_fmts[POWERPC_VPADTL_TYPE], arr[POWERPC_VPADTL_TYPE]);
+}
+
+/*
+ * Process the PERF_RECORD_AUXTRACE_INFO records and setup
+ * the infrastructure to process auxtrace events. PERF_RECORD_AUXTRACE_INFO
+ * is processed first since it is of type perf_user_event_type.
+ * Initialise the aux buffer queues using auxtrace_queues__init().
+ * auxtrace_queue is created for each CPU.
+ */
+int powerpc_vpadtl_process_auxtrace_info(union perf_event *event,
+				  struct perf_session *session)
+{
+	struct perf_record_auxtrace_info *auxtrace_info = &event->auxtrace_info;
+	size_t min_sz = sizeof(u64) * POWERPC_VPADTL_TYPE;
+	struct powerpc_vpadtl *vpa;
+	int err;
+
+	if (auxtrace_info->header.size < sizeof(struct perf_record_auxtrace_info) +
+					min_sz)
+		return -EINVAL;
+
+	vpa = zalloc(sizeof(struct powerpc_vpadtl));
+	if (!vpa)
+		return -ENOMEM;
+
+	err = auxtrace_queues__init(&vpa->queues);
+	if (err)
+		goto err_free;
+
+	vpa->session = session;
+	vpa->machine = &session->machines.host; /* No kvm support */
+	vpa->auxtrace_type = auxtrace_info->type;
+	vpa->pmu_type = auxtrace_info->priv[POWERPC_VPADTL_TYPE];
+
+	vpa->auxtrace.process_event = powerpc_vpadtl_process_event;
+	vpa->auxtrace.process_auxtrace_event = powerpc_vpadtl_process_auxtrace_event;
+	vpa->auxtrace.flush_events = powerpc_vpadtl_flush;
+	vpa->auxtrace.free_events = powerpc_vpadtl_free_events;
+	vpa->auxtrace.free = powerpc_vpadtl_free;
+	session->auxtrace = &vpa->auxtrace;
+
+	powerpc_vpadtl_print_info(&auxtrace_info->priv[0]);
+
+	return 0;
+
+err_free:
+	free(vpa);
+	return err;
+}
-- 
2.47.1



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