[PATCH v2 11/13] perf: cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet
James Clark
james.clark at arm.com
Wed Jul 20 09:07:02 PDT 2022
On 04/07/2022 09:11, Mike Leach wrote:
> When using dynamically assigned CoreSight trace IDs the drivers can output
> the ID / CPU association as a PERF_RECORD_AUX_OUTPUT_HW_ID packet.
>
> Update cs-etm decoder to handle this packet by setting the CPU/Trace ID
> mapping.
>
> Signed-off-by: Mike Leach <mike.leach at linaro.org>
> ---
> tools/include/linux/coresight-pmu.h | 14 ++
> .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 9 +
> tools/perf/util/cs-etm.c | 167 +++++++++++++++++-
> 3 files changed, 185 insertions(+), 5 deletions(-)
>
> diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
> index 31d007fab3a6..4e8b3148f939 100644
> --- a/tools/include/linux/coresight-pmu.h
> +++ b/tools/include/linux/coresight-pmu.h
> @@ -7,6 +7,8 @@
> #ifndef _LINUX_CORESIGHT_PMU_H
> #define _LINUX_CORESIGHT_PMU_H
>
> +#include <linux/bits.h>
> +
> #define CORESIGHT_ETM_PMU_NAME "cs_etm"
>
> /*
> @@ -40,4 +42,16 @@
> #define ETM4_CFG_BIT_RETSTK 12
> #define ETM4_CFG_BIT_VMID_OPT 15
>
> +/*
> + * Interpretation of the PERF_RECORD_AUX_OUTPUT_HW_ID payload.
> + * Used to associate a CPU with the CoreSight Trace ID.
> + * [63:16] - unused SBZ
> + * [15:08] - Trace ID
> + * [07:00] - Version
> + */
> +#define CS_AUX_HW_ID_VERSION_MASK GENMASK_ULL(7, 0)
> +#define CS_AUX_HW_ID_TRACE_ID_MASK GENMASK_ULL(15, 8)
> +
> +#define CS_AUX_HW_ID_CURR_VERSION 0
> +
> #endif
> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> index 31fa3b45134a..d1dd73310707 100644
> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> @@ -611,6 +611,8 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
> return resp;
> }
>
> +#define CS_TRACE_ID_MASK GENMASK(6, 0)
> +
> static int
> cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
> struct cs_etm_trace_params *t_params,
> @@ -625,6 +627,7 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
> switch (t_params->protocol) {
> case CS_ETM_PROTO_ETMV3:
> case CS_ETM_PROTO_PTM:
> + csid = (t_params->etmv3.reg_idr & CS_TRACE_ID_MASK);
> cs_etm_decoder__gen_etmv3_config(t_params, &config_etmv3);
> decoder->decoder_name = (t_params->protocol == CS_ETM_PROTO_ETMV3) ?
> OCSD_BUILTIN_DCD_ETMV3 :
> @@ -632,11 +635,13 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
> trace_config = &config_etmv3;
> break;
> case CS_ETM_PROTO_ETMV4i:
> + csid = (t_params->etmv4.reg_traceidr & CS_TRACE_ID_MASK);
> cs_etm_decoder__gen_etmv4_config(t_params, &trace_config_etmv4);
> decoder->decoder_name = OCSD_BUILTIN_DCD_ETMV4I;
> trace_config = &trace_config_etmv4;
> break;
> case CS_ETM_PROTO_ETE:
> + csid = (t_params->ete.reg_traceidr & CS_TRACE_ID_MASK);
> cs_etm_decoder__gen_ete_config(t_params, &trace_config_ete);
> decoder->decoder_name = OCSD_BUILTIN_DCD_ETE;
> trace_config = &trace_config_ete;
> @@ -645,6 +650,10 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
> return -1;
> }
>
> + /* if the CPU has no trace ID associated, no decoder needed */
> + if (csid == CS_UNUSED_TRACE_ID)
> + return 0;
> +
> if (d_params->operation == CS_ETM_OPERATION_DECODE) {
> if (ocsd_dt_create_decoder(decoder->dcd_tree,
> decoder->decoder_name,
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index df9d67901f8d..ffce858f21fd 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -217,6 +217,139 @@ static int cs_etm__map_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
> return 0;
> }
>
> +static int cs_etm__metadata_get_trace_id(u8 *trace_chan_id, u64 *cpu_metadata)
> +{
> + u64 cs_etm_magic = cpu_metadata[CS_ETM_MAGIC];
> +
> + switch (cs_etm_magic) {
> + case __perf_cs_etmv3_magic:
> + *trace_chan_id = cpu_metadata[CS_ETM_ETMTRACEIDR];
> + break;
> + case __perf_cs_etmv4_magic:
> + case __perf_cs_ete_magic:
> + *trace_chan_id = cpu_metadata[CS_ETMV4_TRCTRACEIDR];
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> +static int cs_etm__metadata_set_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
> +{
> + u64 cs_etm_magic = cpu_metadata[CS_ETM_MAGIC];
> +
> + switch (cs_etm_magic) {
> + case __perf_cs_etmv3_magic:
> + cpu_metadata[CS_ETM_ETMTRACEIDR] = trace_chan_id;
> + break;
> + case __perf_cs_etmv4_magic:
> + case __perf_cs_ete_magic:
> + cpu_metadata[CS_ETMV4_TRCTRACEIDR] = trace_chan_id;
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> +/*
> + * FIELD_GET (linux/bitfield.h) not available outside kernel code,
> + * and the header contains too many dependencies to just copy over,
> + * so roll our own based on the original
> + */
> +#define __bf_shf(x) (__builtin_ffsll(x) - 1)
> +#define FIELD_GET(_mask, _reg) \
> + ({ \
> + (typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \
> + })
> +> +/*
> + * Handle the PERF_RECORD_AUX_OUTPUT_HW_ID event.
> + *
> + * The payload associates the Trace ID and the CPU.
> + * The routine is tolerant of seeing multiple packets with the same association,
> + * but a CPU / Trace ID association changing during a session is an error.
> + */
> +static int cs_etm__process_aux_output_hw_id(struct perf_session *session,
> + union perf_event *event)
> +{
> + struct cs_etm_auxtrace *etm;
> + struct perf_sample sample;
> + struct int_node *inode;
> + struct evsel *evsel;
> + u64 *cpu_data;
> + u64 hw_id;
> + int cpu, version, err;
> + u8 trace_chan_id, curr_chan_id;
> +
> + /* extract and parse the HW ID */
> + hw_id = event->aux_output_hw_id.hw_id;
> + version = FIELD_GET(CS_AUX_HW_ID_VERSION_MASK, hw_id);
> + trace_chan_id = FIELD_GET(CS_AUX_HW_ID_TRACE_ID_MASK, hw_id);
> +
> + /* check that we can handle this version */
> + if (version > CS_AUX_HW_ID_CURR_VERSION)
> + return -EINVAL;
> +
> + /* get access to the etm metadata */
> + etm = container_of(session->auxtrace, struct cs_etm_auxtrace, auxtrace);
> + if (!etm || !etm->metadata)
> + return -EINVAL;
> +
> + /* parse the sample to get the CPU */
> + evsel = evlist__event2evsel(session->evlist, event);
> + if (!evsel)
> + return -EINVAL;
> + err = evsel__parse_sample(evsel, event, &sample);
> + if (err)
> + return err;
> + cpu = sample.cpu;
> + if (cpu == -1) {
> + /* no CPU in the sample - possibly recorded with an old version of perf */
> + pr_err("CS_ETM: no CPU AUX_OUTPUT_HW_ID sample. Use compatible perf to record.");
> + return -EINVAL;
> + }
> +
> + /*
> + * look to see if the metadata contains a valid trace ID.
> + * if so we mapped it before and it must be the same as the ID in the packet.
> + */
> + cpu_data = etm->metadata[cpu];
> + err = cs_etm__metadata_get_trace_id(&curr_chan_id, cpu_data);
> + if (err)
> + return err;
> + if (CS_IS_VALID_TRACE_ID(curr_chan_id) && (curr_chan_id != trace_chan_id)) {
> + pr_err("CS_ETM: mismatch between CPU trace ID and HW_ID packet ID\n");
> + return -EINVAL;
> + }
> +
> + /* next see if the ID is mapped to a CPU, and it matches the current CPU */
> + inode = intlist__find(traceid_list, trace_chan_id);
> + if (inode) {
> + cpu_data = inode->priv;
> + if ((int)cpu_data[CS_ETM_CPU] != cpu) {
> + pr_err("CS_ETM: map mismatch between HW_ID packet CPU and Trace ID\n");
> + return -EINVAL;
> + }
> + return 0;
> + }
> +
> + /* not one we've seen before - lets map it */
> + err = cs_etm__map_trace_id(trace_chan_id, cpu_data);
> + if (err)
> + return err;
> +
> + /*
> + * if we are picking up the association from the packet, need to plug
> + * the correct trace ID into the metadata for setting up decoders later.
> + */
> + err = cs_etm__metadata_set_trace_id(trace_chan_id, cpu_data);
> + return err;
> +}
> +
> void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
> u8 trace_chan_id)
> {
> @@ -2433,6 +2566,8 @@ static int cs_etm__process_event(struct perf_session *session,
> return cs_etm__process_itrace_start(etm, event);
> else if (event->header.type == PERF_RECORD_SWITCH_CPU_WIDE)
> return cs_etm__process_switch_cpu_wide(etm, event);
> + else if (event->header.type == PERF_RECORD_AUX_OUTPUT_HW_ID)
> + return cs_etm__process_aux_output_hw_id(session, event);
This shouldn't need to be handled here because of the peek at the beginning. Although
it's probably harmless to do it twice, it can make deciphering the flow quite difficult.
>
> if (!etm->timeless_decoding && event->header.type == PERF_RECORD_AUX) {
> /*
> @@ -2662,7 +2797,7 @@ static void cs_etm__print_auxtrace_info(__u64 *val, int num)
> for (i = CS_HEADER_VERSION_MAX; cpu < num; cpu++) {
> if (version == 0)
> err = cs_etm__print_cpu_metadata_v0(val, &i);
> - else if (version == 1)
> + else if (version == 1 || version == 2)
> err = cs_etm__print_cpu_metadata_v1(val, &i);
> if (err)
> return;
> @@ -2774,11 +2909,16 @@ static int cs_etm__queue_aux_fragment(struct perf_session *session, off_t file_o
> }
>
> /*
> - * In per-thread mode, CPU is set to -1, but TID will be set instead. See
> - * auxtrace_mmap_params__set_idx(). Return 'not found' if neither CPU nor TID match.
> + * In per-thread mode, auxtrace CPU is set to -1, but TID will be set instead. See
> + * auxtrace_mmap_params__set_idx(). However, the sample AUX event will contain a
> + * CPU as we set this always for the AUX_OUTPUT_HW_ID event.
> + * So now compare only TIDs if auxtrace CPU is -1, and CPUs if auxtrace CPU is not -1.
> + * Return 'not found' if mismatch.
> */
> - if ((auxtrace_event->cpu == (__u32) -1 && auxtrace_event->tid != sample->tid) ||
> - auxtrace_event->cpu != sample->cpu)
> + if (auxtrace_event->cpu == (__u32) -1) {
> + if (auxtrace_event->tid != sample->tid)
> + return 1;
> + } else if (auxtrace_event->cpu != sample->cpu)
> return 1;
>
> if (aux_event->flags & PERF_AUX_FLAG_OVERWRITE) {
> @@ -2827,6 +2967,15 @@ static int cs_etm__queue_aux_fragment(struct perf_session *session, off_t file_o
> return 1;
> }
>
> +static int cs_etm__process_aux_hw_id_cb(struct perf_session *session, union perf_event *event,
> + u64 offset __maybe_unused, void *data __maybe_unused)
> +{
> + /* look to handle PERF_RECORD_AUX_OUTPUT_HW_ID early to ensure decoders can be set up */
> + if (event->header.type == PERF_RECORD_AUX_OUTPUT_HW_ID)
> + return cs_etm__process_aux_output_hw_id(session, event);
> + return 0;
> +}
I couldn't see the relationship between the two peeks and why they couldn't be done together
in one pass. I changed it so cs_etm__process_aux_hw_id_cb() is also called on the peek
to queue the aux records and it seemed to work. At least just opening the file and glancing.
If there is some dependency though, I don't think two passes is excessive.
> +
> static int cs_etm__queue_aux_records_cb(struct perf_session *session, union perf_event *event,
> u64 offset __maybe_unused, void *data __maybe_unused)
> {
> @@ -3109,6 +3258,14 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
> if (err)
> goto err_delete_thread;
>
> + /* scan for AUX_OUTPUT_HW_ID records */
> + if (hdr_version >= CS_AUX_HW_ID_VERSION_MIN) {
> + err = perf_session__peek_events(session, session->header.data_offset,
> + session->header.data_size,
> + cs_etm__process_aux_hw_id_cb, NULL);
This no longer works at all with piping because of this line in peek_events:
if (perf_data__is_pipe(session->data))
return -1;
So we should change the warning message to an error and exit earlier:
if (!etm->data_queued)
pr_warning("CS ETM warning: Coresight decode and TRBE support requires random file access.\n"
"Continuing with best effort decoding in piped mode.\n\n");
And then we can also remove all the now dead code and variables related to piping like:
etm->data_queued = etm->queues.populated;
...
if (!etm->data_queued) {
...
}
> + if (err)
> + goto err_delete_thread;
> + }
> err = cs_etm__queue_aux_records(session);
> if (err)
> goto err_delete_thread;
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