Re: [PATCH v2 3/6] perf stat: Basic support for iiostat in perf

[Namhyung Kim <namhyung@kernel.org>]

On Wed, Dec 23, 2020 at 10:03 PM Alexander Antonov
<alexander.antonov@linux.intel.com> wrote:
>
> Add basic flow for a new iiostat mode in perf. Mode is intended to
> provide four I/O performance metrics per each IIO stack: Inbound Read,
> Inbound Write, Outbound Read, Outbound Write.

It seems like a generic analysis and other archs can extend it later..
Then we can make it a bit more general.. at least, names? :)

>
> The actual code to compute the metrics and attribute it to
> evsel::perf_device is in follow-on patches.
>
> Signed-off-by: Alexander Antonov <alexander.antonov@linux.intel.com>
> ---
>  tools/perf/builtin-stat.c      | 33 ++++++++++++++++++++++++++++-
>  tools/perf/util/iiostat.h      | 33 +++++++++++++++++++++++++++++
>  tools/perf/util/stat-display.c | 38 +++++++++++++++++++++++++++++++++-
>  tools/perf/util/stat-shadow.c  | 11 +++++++++-
>  tools/perf/util/stat.h         |  1 +
>  5 files changed, 113 insertions(+), 3 deletions(-)
>  create mode 100644 tools/perf/util/iiostat.h
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 72f9d0aa3f96..14c3da136927 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -67,6 +67,7 @@
>  #include "util/top.h"
>  #include "util/affinity.h"
>  #include "util/pfm.h"
> +#include "util/iiostat.h"
>  #include "asm/bug.h"
>
>  #include <linux/time64.h>
> @@ -198,7 +199,8 @@ static struct perf_stat_config stat_config = {
>         .walltime_nsecs_stats   = &walltime_nsecs_stats,
>         .big_num                = true,
>         .ctl_fd                 = -1,
> -       .ctl_fd_ack             = -1
> +       .ctl_fd_ack             = -1,
> +       .iiostat_run            = false,
>  };
>
>  static bool cpus_map_matched(struct evsel *a, struct evsel *b)
> @@ -1073,6 +1075,14 @@ static int parse_stat_cgroups(const struct option *opt,
>         return parse_cgroups(opt, str, unset);
>  }
>
> +__weak int iiostat_parse(const struct option *opt __maybe_unused,
> +                        const char *str __maybe_unused,
> +                        int unset __maybe_unused)
> +{
> +       pr_err("iiostat mode is not supported\n");
> +       return -1;
> +}
> +
>  static struct option stat_options[] = {
>         OPT_BOOLEAN('T', "transaction", &transaction_run,
>                     "hardware transaction statistics"),
> @@ -1185,6 +1195,8 @@ static struct option stat_options[] = {
>                      "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n"
>                      "\t\t\t  Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.",
>                       parse_control_option),
> +       OPT_CALLBACK_OPTARG(0, "iiostat", &evsel_list, &stat_config, "root port",
> +                           "measure PCIe metrics per IIO stack", iiostat_parse),
>         OPT_END()
>  };
>
> @@ -1509,6 +1521,12 @@ static int perf_stat_init_aggr_mode_file(struct perf_stat *st)
>         return 0;
>  }
>
> +__weak int iiostat_show_root_ports(struct evlist *evlist __maybe_unused,
> +                                  struct perf_stat_config *config __maybe_unused)
> +{
> +       return 0;
> +}

I think it's too specific, maybe iiostat_prepare() ?

> +
>  /*
>   * Add default attributes, if there were no attributes specified or
>   * if -d/--detailed, -d -d or -d -d -d is used:
> @@ -2054,6 +2072,10 @@ static void setup_system_wide(int forks)
>         }
>  }
>
> +__weak void iiostat_delete_root_ports(struct evlist *evlist __maybe_unused)
> +{
> +}

Same here..

> +
>  int cmd_stat(int argc, const char **argv)
>  {
>         const char * const stat_usage[] = {
> @@ -2230,6 +2252,12 @@ int cmd_stat(int argc, const char **argv)
>                 goto out;
>         }
>
> +       if (stat_config.iiostat_run) {
> +               status = iiostat_show_root_ports(evsel_list, &stat_config);
> +               if (status || !stat_config.iiostat_run)
> +                       goto out;
> +       }
> +
>         if (add_default_attributes())
>                 goto out;
>
> @@ -2406,6 +2434,9 @@ int cmd_stat(int argc, const char **argv)
>         perf_stat__exit_aggr_mode();
>         perf_evlist__free_stats(evsel_list);
>  out:
> +       if (stat_config.iiostat_run)
> +               iiostat_delete_root_ports(evsel_list);
> +
>         zfree(&stat_config.walltime_run);
>
>         if (smi_cost && smi_reset)
> diff --git a/tools/perf/util/iiostat.h b/tools/perf/util/iiostat.h
> new file mode 100644
> index 000000000000..8d4226df9975
> --- /dev/null
> +++ b/tools/perf/util/iiostat.h
> @@ -0,0 +1,33 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * perf iiostat
> + *
> + * Copyright (C) 2020, Intel Corporation
> + *
> + * Authors: Alexander Antonov <alexander.antonov@linux.intel.com>
> + */
> +
> +#ifndef _IIOSTAT_H
> +#define _IIOSTAT_H
> +
> +#include <subcmd/parse-options.h>
> +#include "util/stat.h"
> +#include "util/parse-events.h"
> +#include "util/evlist.h"
> +
> +struct option;
> +struct perf_stat_config;
> +struct evlist;
> +struct timespec;
> +
> +int iiostat_parse(const struct option *opt, const char *str,
> +                 int unset __maybe_unused);
> +void iiostat_prefix(struct perf_stat_config *config, struct evlist *evlist,
> +                   char *prefix, struct timespec *ts);
> +void iiostat_print_metric(struct perf_stat_config *config, struct evsel *evsel,
> +                         struct perf_stat_output_ctx *out);
> +int iiostat_show_root_ports(struct evlist *evlist,
> +                           struct perf_stat_config *config);
> +void iiostat_delete_root_ports(struct evlist *evlist);
> +
> +#endif /* _IIOSTAT_H */
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 3bfcdb80443a..9eb8484e8b90 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -17,6 +17,7 @@
>  #include "cgroup.h"
>  #include <api/fs/fs.h>
>  #include "util.h"
> +#include "iiostat.h"
>
>  #define CNTR_NOT_SUPPORTED     "<not supported>"
>  #define CNTR_NOT_COUNTED       "<not counted>"
> @@ -310,6 +311,12 @@ static void print_metric_header(struct perf_stat_config *config,
>         struct outstate *os = ctx;
>         char tbuf[1024];
>
> +       /* In case of iiostat, print metric header for first perf_device only */
> +       if (os->evsel->perf_device && os->evsel->evlist->selected->perf_device &&
> +           config->iiostat_run &&

When is the perf_device set?  Is it possible to be NULL in the iiostat mode?

Thanks,
Namhyung


> +           os->evsel->perf_device != os->evsel->evlist->selected->perf_device)
> +               return;
> +
>         if (!valid_only_metric(unit))
>                 return;
>         unit = fixunit(tbuf, os->evsel, unit);