Re: [PATCH V2 6/6] tools/perf: Enable perf script to present the DTL entries

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

On 15/09/2025 10:27, Athira Rajeev wrote:
> 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])
> 
> Signed-off-by: Athira Rajeev <atrajeev@linux.ibm.com>
> ---
> Changelog:
> 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 | 27 +++++++++++++++++++++++++++
>  tools/perf/util/event.h     |  3 +++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index d9fbdcf72f25..8a03fdbfce5e 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 +2004,30 @@ 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;
> +
> +	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",\

Unnecessary line continuation, also line length exceeds 100 columns

> +			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 1;

Other __fprintf_*() are returning the number of char printed.

> +}
> +#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 +2050,8 @@ 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;