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b74683b3bb
When running topdown leader smapling test on Intel hybrid platforms,
such as LNL/ARL, we see the below error.
Topdown leader sampling test
Topdown leader sampling [Failed topdown events not reordered correctly]
It indciates the below command fails.
perf record -o "${perfdata}" -e "{instructions,slots,topdown-retiring}:S" true
The root cause is that perf tool creats a perf event for each PMU type
if it can create.
As for this command, there would be 5 perf events created,
cpu_atom/instructions/,cpu_atom/topdown_retiring/,
cpu_core/slots/,cpu_core/instructions/,cpu_core/topdown-retiring/
For these 5 events, the 2 cpu_atom events are in a group and the other 3
cpu_core events are in another group.
When arch_topdown_sample_read() traverses all these 5 events, events
cpu_atom/instructions/ and cpu_core/slots/ don't have a same group
leade, and then return false directly and lead to cpu_core/slots/ event
is used to sample and this is not allowed by PMU driver.
It's a overkill to return false directly if "evsel->core.leader !=
leader->core.leader" since there could be multiple groups in the event
list.
Just "continue" instead of "return false" to fix this issue.
Fixes: 1e53e9d178 ("perf x86/topdown: Correct leader selection with sample_read enabled")
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Thomas Falcon <thomas.falcon@intel.com>
Tested-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250307023906.1135613-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
91 lines
2.1 KiB
C
91 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "api/fs/fs.h"
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#include "util/evsel.h"
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#include "util/evlist.h"
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#include "util/pmu.h"
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#include "util/pmus.h"
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#include "util/topdown.h"
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#include "topdown.h"
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#include "evsel.h"
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/* Check whether there is a PMU which supports the perf metrics. */
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bool topdown_sys_has_perf_metrics(void)
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{
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static bool has_perf_metrics;
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static bool cached;
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struct perf_pmu *pmu;
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if (cached)
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return has_perf_metrics;
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/*
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* The perf metrics feature is a core PMU feature.
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* The PERF_TYPE_RAW type is the type of a core PMU.
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* The slots event is only available when the core PMU
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* supports the perf metrics feature.
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*/
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pmu = perf_pmus__find_by_type(PERF_TYPE_RAW);
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if (pmu && perf_pmu__have_event(pmu, "slots"))
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has_perf_metrics = true;
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cached = true;
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return has_perf_metrics;
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}
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#define TOPDOWN_SLOTS 0x0400
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bool arch_is_topdown_slots(const struct evsel *evsel)
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{
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if (evsel->core.attr.config == TOPDOWN_SLOTS)
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return true;
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return false;
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}
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bool arch_is_topdown_metrics(const struct evsel *evsel)
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{
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int config = evsel->core.attr.config;
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const char *name_from_config;
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struct perf_pmu *pmu;
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/* All topdown events have an event code of 0. */
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if ((config & 0xFF) != 0)
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return false;
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pmu = evsel__find_pmu(evsel);
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if (!pmu || !pmu->is_core)
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return false;
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name_from_config = perf_pmu__name_from_config(pmu, config);
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return name_from_config && strcasestr(name_from_config, "topdown");
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}
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/*
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* Check whether a topdown group supports sample-read.
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*
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* Only Topdown metric supports sample-read. The slots
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* event must be the leader of the topdown group.
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*/
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bool arch_topdown_sample_read(struct evsel *leader)
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{
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struct evsel *evsel;
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if (!evsel__sys_has_perf_metrics(leader))
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return false;
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if (!arch_is_topdown_slots(leader))
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return false;
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/*
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* If slots event as leader event but no topdown metric events
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* in group, slots event should still sample as leader.
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*/
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evlist__for_each_entry(leader->evlist, evsel) {
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if (evsel->core.leader != leader->core.leader)
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continue;
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if (evsel != leader && arch_is_topdown_metrics(evsel))
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return true;
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}
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return false;
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}
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