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

[Adrian Hunter <adrian.hunter@intel.com>]

On 15/08/2025 11:34, Athira Rajeev wrote:
> 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@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"

Are all these #includes really needed

> +
> +/*
> + * 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;
> +};

struct dtl_entry is moved in a later patch.
Maybe call it vpadtl_entry or powerpc_vpadtl_entry and
put it in perf/util/event.h since it is eventually needed
in perf/builtin-script.c

> +
> +/*
> + * 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

sizeof(struct dtl_entry) ?

> +
> +/*
> + * 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;

dtl_entry_size ?

> +		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));

Lines are getting a bit long

> +		} 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);

Might be worth adding a helper like

static struct powerpc_vpadtl *session_to_vpa(struct perf_session *session)
{
	return 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);

auxtrace_queues__add_event() is only needed here if there is no
auxtrace index, however an auxtrace index is always written for
new perf.data files.  The index gets processed and data queued
by auxtrace_queues__process_index() which is added in patch 11.

Piped data, on the other hand, has no index and needs to be
handled here.

So:

	if (perf_data__is_pipe(session->data)) {
		err = auxtrace_queues__add_event(&vpa->queues, session, event, 0, &buffer);
		if (err)
			return err;
	}


> +	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);

Unnecessary line wrap

> +			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);

This is the same as free(queues->queue_array[i].priv)

> +		queues->queue_array[i].priv = NULL;

Could all be reduced to zfree(queues->queue_array[i].priv)

> +	}
> +	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;
> +}