Re: [PATCH v3] perf mem: enable sampling loads and stores simultaneously

[Stephane Eranian <eranian@google.com>]

On Wed, Dec 17, 2014 at 11:07 AM, Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
> Em Wed, Dec 17, 2014 at 04:23:55PM +0100, Stephane Eranian escreveu:
>>
>> This patch modifies perf mem to default to sampling loads
>> and stores simultaneously. It could only do one or the other
>> before yet there was no hardware restriction preventing
>> simultaneous collection. With this patch, one run is sufficient
>> to collect both.
>>
>> It is still possible to sample only loads or stores by using the
>> -t option:
>>  $ perf mem -t load rec
>>  $ perf mem -t load rep
>> Or
>>  $ perf mem -t store rec
>>  $ perf mem -t store rep
>>
>> The perf report TUI will show one event at a time. The store
>> output will contain a Weight column which will be empty.
>>
>> In V2, we updated the man pages to reflect the change and
>> also simplify the initialization of the argv vector passed
>> to the cmd_*() functions as per LKML feedback.
>>
>> In V3, we fixed typos in the changelog.
>>
>> Signed-off-by: Stephane Eranian <eranian@google.com>
>
> So here it goes a v4, just a minor change to avoid adding another global
> variable and make this operation parm like the other parms inside that
> struct perf_mem, attached goes the interdiff from your patch to this one
> here, ok?
>
So you want me to post V4 with this one? I am fine if you add yours
directly on top of mine.

Acked-by: Stephane Eranian <eranian@google.com>

> diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt
> index 1d78a4064da4..43310d8661fe 100644
> --- a/tools/perf/Documentation/perf-mem.txt
> +++ b/tools/perf/Documentation/perf-mem.txt
> @@ -12,11 +12,12 @@ SYNOPSIS
>
>  DESCRIPTION
>  -----------
> -"perf mem -t <TYPE> record" runs a command and gathers memory operation data
> +"perf mem record" runs a command and gathers memory operation data
>  from it, into perf.data. Perf record options are accepted and are passed through.
>
> -"perf mem -t <TYPE> report" displays the result. It invokes perf report with the
> -right set of options to display a memory access profile.
> +"perf mem report" displays the result. It invokes perf report with the
> +right set of options to display a memory access profile. By default, loads
> +and stores are sampled. Use the -t option to limit to loads or stores.
>
>  Note that on Intel systems the memory latency reported is the use-latency,
>  not the pure load (or store latency). Use latency includes any pipeline
> @@ -29,7 +30,7 @@ OPTIONS
>
>  -t::
>  --type=::
> -       Select the memory operation type: load or store (default: load)
> +       Select the memory operation type: load or store (default: load,store)
>
>  -D::
>  --dump-raw-samples=::
> diff --git a/tools/perf/builtin-mem.c b/tools/perf/builtin-mem.c
> index 24db6ffe2957..9b5663950a4d 100644
> --- a/tools/perf/builtin-mem.c
> +++ b/tools/perf/builtin-mem.c
> @@ -7,44 +7,47 @@
>  #include "util/session.h"
>  #include "util/data.h"
>
> -#define MEM_OPERATION_LOAD     "load"
> -#define MEM_OPERATION_STORE    "store"
> -
> -static const char      *mem_operation          = MEM_OPERATION_LOAD;
> +#define MEM_OPERATION_LOAD     0x1
> +#define MEM_OPERATION_STORE    0x2
>
>  struct perf_mem {
>         struct perf_tool        tool;
>         char const              *input_name;
>         bool                    hide_unresolved;
>         bool                    dump_raw;
> +       int                     operation;
>         const char              *cpu_list;
>         DECLARE_BITMAP(cpu_bitmap, MAX_NR_CPUS);
>  };
>
> -static int __cmd_record(int argc, const char **argv)
> +static int __cmd_record(int argc, const char **argv, struct perf_mem *mem)
>  {
>         int rec_argc, i = 0, j;
>         const char **rec_argv;
> -       char event[64];
>         int ret;
>
> -       rec_argc = argc + 4;
> +       rec_argc = argc + 7; /* max number of arguments */
>         rec_argv = calloc(rec_argc + 1, sizeof(char *));
>         if (!rec_argv)
>                 return -1;
>
> -       rec_argv[i++] = strdup("record");
> -       if (!strcmp(mem_operation, MEM_OPERATION_LOAD))
> -               rec_argv[i++] = strdup("-W");
> -       rec_argv[i++] = strdup("-d");
> -       rec_argv[i++] = strdup("-e");
> +       rec_argv[i++] = "record";
>
> -       if (strcmp(mem_operation, MEM_OPERATION_LOAD))
> -               sprintf(event, "cpu/mem-stores/pp");
> -       else
> -               sprintf(event, "cpu/mem-loads/pp");
> +       if (mem->operation & MEM_OPERATION_LOAD)
> +               rec_argv[i++] = "-W";
> +
> +       rec_argv[i++] = "-d";
> +
> +       if (mem->operation & MEM_OPERATION_LOAD) {
> +               rec_argv[i++] = "-e";
> +               rec_argv[i++] = "cpu/mem-loads/pp";
> +       }
> +
> +       if (mem->operation & MEM_OPERATION_STORE) {
> +               rec_argv[i++] = "-e";
> +               rec_argv[i++] = "cpu/mem-stores/pp";
> +       }
>
> -       rec_argv[i++] = strdup(event);
>         for (j = 1; j < argc; j++, i++)
>                 rec_argv[i] = argv[j];
>
> @@ -162,17 +165,17 @@ static int report_events(int argc, const char **argv, struct perf_mem *mem)
>         if (!rep_argv)
>                 return -1;
>
> -       rep_argv[i++] = strdup("report");
> -       rep_argv[i++] = strdup("--mem-mode");
> -       rep_argv[i++] = strdup("-n"); /* display number of samples */
> +       rep_argv[i++] = "report";
> +       rep_argv[i++] = "--mem-mode";
> +       rep_argv[i++] = "-n"; /* display number of samples */
>
>         /*
>          * there is no weight (cost) associated with stores, so don't print
>          * the column
>          */
> -       if (strcmp(mem_operation, MEM_OPERATION_LOAD))
> -               rep_argv[i++] = strdup("--sort=mem,sym,dso,symbol_daddr,"
> -                                      "dso_daddr,tlb,locked");
> +       if (!(mem->operation & MEM_OPERATION_LOAD))
> +               rep_argv[i++] = "--sort=mem,sym,dso,symbol_daddr,"
> +                               "dso_daddr,tlb,locked";
>
>         for (j = 1; j < argc; j++, i++)
>                 rep_argv[i] = argv[j];
> @@ -182,6 +185,75 @@ static int report_events(int argc, const char **argv, struct perf_mem *mem)
>         return ret;
>  }
>
> +struct mem_mode {
> +       const char *name;
> +       int mode;
> +};
> +
> +#define MEM_OPT(n, m) \
> +       { .name = n, .mode = (m) }
> +
> +#define MEM_END { .name = NULL }
> +
> +static const struct mem_mode mem_modes[]={
> +       MEM_OPT("load", MEM_OPERATION_LOAD),
> +       MEM_OPT("store", MEM_OPERATION_STORE),
> +       MEM_END
> +};
> +
> +static int
> +parse_mem_ops(const struct option *opt, const char *str, int unset)
> +{
> +       int *mode = (int *)opt->value;
> +       const struct mem_mode *m;
> +       char *s, *os = NULL, *p;
> +       int ret = -1;
> +
> +       if (unset)
> +               return 0;
> +
> +       /* str may be NULL in case no arg is passed to -t */
> +       if (str) {
> +               /* because str is read-only */
> +               s = os = strdup(str);
> +               if (!s)
> +                       return -1;
> +
> +               /* reset mode */
> +               *mode = 0;
> +
> +               for (;;) {
> +                       p = strchr(s, ',');
> +                       if (p)
> +                               *p = '\0';
> +
> +                       for (m = mem_modes; m->name; m++) {
> +                               if (!strcasecmp(s, m->name))
> +                                       break;
> +                       }
> +                       if (!m->name) {
> +                               fprintf(stderr, "unknown sampling op %s,"
> +                                           " check man page\n", s);
> +                               goto error;
> +                       }
> +
> +                       *mode |= m->mode;
> +
> +                       if (!p)
> +                               break;
> +
> +                       s = p + 1;
> +               }
> +       }
> +       ret = 0;
> +
> +       if (*mode == 0)
> +               *mode = MEM_OPERATION_LOAD;
> +error:
> +       free(os);
> +       return ret;
> +}
> +
>  int cmd_mem(int argc, const char **argv, const char *prefix __maybe_unused)
>  {
>         struct stat st;
> @@ -197,10 +269,15 @@ int cmd_mem(int argc, const char **argv, const char *prefix __maybe_unused)
>                         .ordered_events = true,
>                 },
>                 .input_name              = "perf.data",
> +               /*
> +                * default to both load an store sampling
> +                */
> +               .operation               = MEM_OPERATION_LOAD | MEM_OPERATION_STORE,
>         };
>         const struct option mem_options[] = {
> -       OPT_STRING('t', "type", &mem_operation,
> -                  "type", "memory operations(load/store)"),
> +       OPT_CALLBACK('t', "type", &mem.operation,
> +                  "type", "memory operations(load,store) Default load,store",
> +                   parse_mem_ops),
>         OPT_BOOLEAN('D', "dump-raw-samples", &mem.dump_raw,
>                     "dump raw samples in ASCII"),
>         OPT_BOOLEAN('U', "hide-unresolved", &mem.hide_unresolved,
> @@ -225,7 +302,7 @@ int cmd_mem(int argc, const char **argv, const char *prefix __maybe_unused)
>         argc = parse_options_subcommand(argc, argv, mem_options, mem_subcommands,
>                                         mem_usage, PARSE_OPT_STOP_AT_NON_OPTION);
>
> -       if (!argc || !(strncmp(argv[0], "rec", 3) || mem_operation))
> +       if (!argc || !(strncmp(argv[0], "rec", 3) || mem.operation))
>                 usage_with_options(mem_usage, mem_options);
>
>         if (!mem.input_name || !strlen(mem.input_name)) {
> @@ -236,7 +313,7 @@ int cmd_mem(int argc, const char **argv, const char *prefix __maybe_unused)
>         }
>
>         if (!strncmp(argv[0], "rec", 3))
> -               return __cmd_record(argc, argv);
> +               return __cmd_record(argc, argv, &mem);
>         else if (!strncmp(argv[0], "rep", 3))
>                 return report_events(argc, argv, &mem);
>         else