mirror of https://github.com/torvalds/linux.git
76 lines
1.6 KiB
C
76 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <stdio.h>
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#include "api/fs/fs.h"
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#include "util/pmu.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_pmu__find_by_type(PERF_TYPE_RAW);
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if (pmu && pmu_have_event(pmu->name, "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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/*
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* Check whether we can use a group for top down.
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* Without a group may get bad results due to multiplexing.
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*/
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bool arch_topdown_check_group(bool *warn)
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{
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int n;
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if (sysctl__read_int("kernel/nmi_watchdog", &n) < 0)
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return false;
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if (n > 0) {
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*warn = true;
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return false;
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}
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return true;
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}
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void arch_topdown_group_warn(void)
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{
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fprintf(stderr,
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"nmi_watchdog enabled with topdown. May give wrong results.\n"
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"Disable with echo 0 > /proc/sys/kernel/nmi_watchdog\n");
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}
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#define TOPDOWN_SLOTS 0x0400
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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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if (!evsel__sys_has_perf_metrics(leader))
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return false;
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if (leader->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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