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    Subject[PATCH 5.17 130/298] perf record: Support sample-read topdown metric group for hybrid platforms
    Date
    From: Zhengjun Xing <zhengjun.xing@linux.intel.com>

    [ Upstream commit 151e7d75036b4e2ac0f33730bc1a5b3ff424d9a7 ]

    With the hardware TopDown metrics feature, the sample-read feature should
    be supported for a TopDown group, e.g., sample a non-topdown event and read
    a Topdown metric group. But the current perf record code errors are out.

    For a TopDown metric group,the slots event must be the leader of the group,
    but the leader slots event doesn't support sampling. To support sample-read
    the TopDown metric group, uses the 2nd event of the group as the "leader"
    for the purposes of sampling.

    Only the platform with the TopDown metric feature supports sample-read the
    topdown group. In commit acb65150a47c ("perf record: Support sample-read
    topdown metric group"), it adds arch_topdown_sample_read() to indicate
    whether the TopDown group supports sample-read, it should only work on the
    non-hybrid systems, this patch extends the support for hybrid platforms.

    Before:

    # ./perf record -e "{cpu_core/slots/,cpu_core/cycles/,cpu_core/topdown-retiring/}:S" -a sleep 1
    Error:
    The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cpu_core/topdown-retiring/).
    /bin/dmesg | grep -i perf may provide additional information.

    After:

    # ./perf record -e "{cpu_core/slots/,cpu_core/cycles/,cpu_core/topdown-retiring/}:S" -a sleep 1
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.238 MB perf.data (369 samples) ]

    Fixes: acb65150a47c2bae ("perf record: Support sample-read topdown metric group")
    Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
    Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
    Acked-by: Ian Rogers <irogers@google.com>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Alexander Shishkin <alexander.shishkin@intel.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: https://lore.kernel.org/r/20220602153603.1884710-1-zhengjun.xing@linux.intel.com
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/perf/arch/x86/util/evsel.c | 3 ++-
    tools/perf/arch/x86/util/evsel.h | 7 +++++++
    tools/perf/arch/x86/util/topdown.c | 21 ++++-----------------
    3 files changed, 13 insertions(+), 18 deletions(-)
    create mode 100644 tools/perf/arch/x86/util/evsel.h

    diff --git a/tools/perf/arch/x86/util/evsel.c b/tools/perf/arch/x86/util/evsel.c
    index ff4561b7b600..3501399cef35 100644
    --- a/tools/perf/arch/x86/util/evsel.c
    +++ b/tools/perf/arch/x86/util/evsel.c
    @@ -5,6 +5,7 @@
    #include "util/env.h"
    #include "util/pmu.h"
    #include "linux/string.h"
    +#include "evsel.h"

    void arch_evsel__set_sample_weight(struct evsel *evsel)
    {
    @@ -32,7 +33,7 @@ void arch_evsel__fixup_new_cycles(struct perf_event_attr *attr)
    }

    /* Check whether the evsel's PMU supports the perf metrics */
    -static bool evsel__sys_has_perf_metrics(const struct evsel *evsel)
    +bool evsel__sys_has_perf_metrics(const struct evsel *evsel)
    {
    const char *pmu_name = evsel->pmu_name ? evsel->pmu_name : "cpu";

    diff --git a/tools/perf/arch/x86/util/evsel.h b/tools/perf/arch/x86/util/evsel.h
    new file mode 100644
    index 000000000000..19ad1691374d
    --- /dev/null
    +++ b/tools/perf/arch/x86/util/evsel.h
    @@ -0,0 +1,7 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +#ifndef _EVSEL_H
    +#define _EVSEL_H 1
    +
    +bool evsel__sys_has_perf_metrics(const struct evsel *evsel);
    +
    +#endif
    diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
    index f4d5422e9960..f81a7cfe4d63 100644
    --- a/tools/perf/arch/x86/util/topdown.c
    +++ b/tools/perf/arch/x86/util/topdown.c
    @@ -4,6 +4,7 @@
    #include "util/pmu.h"
    #include "util/topdown.h"
    #include "topdown.h"
    +#include "evsel.h"

    /* Check whether there is a PMU which supports the perf metrics. */
    bool topdown_sys_has_perf_metrics(void)
    @@ -55,33 +56,19 @@ void arch_topdown_group_warn(void)

    #define TOPDOWN_SLOTS 0x0400

    -static bool is_topdown_slots_event(struct evsel *counter)
    -{
    - if (!counter->pmu_name)
    - return false;
    -
    - if (strcmp(counter->pmu_name, "cpu"))
    - return false;
    -
    - if (counter->core.attr.config == TOPDOWN_SLOTS)
    - return true;
    -
    - return false;
    -}
    -
    /*
    * Check whether a topdown group supports sample-read.
    *
    - * Only Topdown metic supports sample-read. The slots
    + * Only Topdown metric supports sample-read. The slots
    * event must be the leader of the topdown group.
    */

    bool arch_topdown_sample_read(struct evsel *leader)
    {
    - if (!pmu_have_event("cpu", "slots"))
    + if (!evsel__sys_has_perf_metrics(leader))
    return false;

    - if (is_topdown_slots_event(leader))
    + if (leader->core.attr.config == TOPDOWN_SLOTS)
    return true;

    return false;
    --
    2.35.1


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