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    Subject[PATCH v3 3/4] perf utils: Add helper function is_pmu_core to detect PMU CORE devices
    Date
    On some platforms, PMU core devices sysfs name is not cpu.
    Adding function is_pmu_core to detect as core device using
    core device specific hints in sysfs.

    For arm64 platforms, all core devices have file "cpus" in sysfs.

    Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
    ---
    tools/perf/util/pmu.c | 44 ++++++++++++++++++++++++++++++++++++++++----
    1 file changed, 40 insertions(+), 4 deletions(-)

    diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
    index aefdbd1..0057d1c 100644
    --- a/tools/perf/util/pmu.c
    +++ b/tools/perf/util/pmu.c
    @@ -506,6 +506,39 @@ static struct cpu_map *pmu_cpumask(const char *name)
    }

    /*
    + * PMU CORE devices have different name other than cpu in sysfs on some
    + * platforms. looking for possible sysfs files to identify as core device.
    + */
    +static int is_pmu_core(const char *name)
    +{
    + struct stat st;
    + char path[PATH_MAX];
    + const char *sysfs = sysfs__mountpoint();
    + const char **template;
    + const char *templates[] = {
    + "%s/bus/event_source/devices/%s/cpus",
    + NULL
    + };
    +
    + if (!sysfs)
    + return 0;
    +
    + /* Look for cpu sysfs */
    + snprintf(path, PATH_MAX, "%s/bus/event_source/devices/cpu", sysfs);
    + if ((stat(path, &st) == 0) &&
    + (strncmp(name, "cpu", strlen("cpu")) == 0))
    + return 1;
    +
    + for (template = templates; *template; template++) {
    + snprintf(path, PATH_MAX, *template, sysfs, name);
    + if (stat(path, &st) == 0)
    + return 1;
    + }
    +
    + return 0;
    +}
    +
    +/*
    * Return the CPU id as a raw string.
    *
    * Each architecture should provide a more precise id string that
    @@ -558,15 +591,18 @@ static void pmu_add_cpu_aliases(struct list_head *head, const char *name,
    */
    i = 0;
    while (1) {
    - const char *pname;

    pe = &map->table[i++];
    if (!pe->name)
    break;

    - pname = pe->pmu ? pe->pmu : "cpu";
    - if (strncmp(pname, name, strlen(pname)))
    - continue;
    + if (!is_pmu_core(name)) {
    + /* check for uncore devices */
    + if (pe->pmu == NULL)
    + continue;
    + if (strncmp(pe->pmu, name, strlen(pe->pmu)))
    + continue;
    + }

    /* need type casts to override 'const' */
    __perf_pmu__new_alias(head, NULL, (char *)pe->name,
    --
    1.8.1.4
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