x86/util/topdown.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <stdio.h>
0003 #include "api/fs/fs.h"
0004 #include "util/pmu.h"
0005 #include "util/topdown.h"
0006 #include "util/evlist.h"
0007 #include "util/debug.h"
0008 #include "util/pmu-hybrid.h"
0009 #include "topdown.h"
0010 #include "evsel.h"
0011
0012 #define TOPDOWN_L1_EVENTS       "{slots,topdown-retiring,topdown-bad-spec,topdown-fe-bound,topdown-be-bound}"
0013 #define TOPDOWN_L1_EVENTS_CORE  "{slots,cpu_core/topdown-retiring/,cpu_core/topdown-bad-spec/,cpu_core/topdown-fe-bound/,cpu_core/topdown-be-bound/}"
0014 #define TOPDOWN_L2_EVENTS       "{slots,topdown-retiring,topdown-bad-spec,topdown-fe-bound,topdown-be-bound,topdown-heavy-ops,topdown-br-mispredict,topdown-fetch-lat,topdown-mem-bound}"
0015 #define TOPDOWN_L2_EVENTS_CORE  "{slots,cpu_core/topdown-retiring/,cpu_core/topdown-bad-spec/,cpu_core/topdown-fe-bound/,cpu_core/topdown-be-bound/,cpu_core/topdown-heavy-ops/,cpu_core/topdown-br-mispredict/,cpu_core/topdown-fetch-lat/,cpu_core/topdown-mem-bound/}"
0016
0017 /* Check whether there is a PMU which supports the perf metrics. */
0018 bool topdown_sys_has_perf_metrics(void)
0019 {
0020     static bool has_perf_metrics;
0021     static bool cached;
0022     struct perf_pmu *pmu;
0023
0024     if (cached)
0025         return has_perf_metrics;
0026
0027     /*
0028      * The perf metrics feature is a core PMU feature.
0029      * The PERF_TYPE_RAW type is the type of a core PMU.
0030      * The slots event is only available when the core PMU
0031      * supports the perf metrics feature.
0032      */
0033     pmu = perf_pmu__find_by_type(PERF_TYPE_RAW);
0034     if (pmu && pmu_have_event(pmu->name, "slots"))
0035         has_perf_metrics = true;
0036
0037     cached = true;
0038     return has_perf_metrics;
0039 }
0040
0041 /*
0042  * Check whether we can use a group for top down.
0043  * Without a group may get bad results due to multiplexing.
0044  */
0045 bool arch_topdown_check_group(bool *warn)
0046 {
0047     int n;
0048
0049     if (sysctl__read_int("kernel/nmi_watchdog", &n) < 0)
0050         return false;
0051     if (n > 0) {
0052         *warn = true;
0053         return false;
0054     }
0055     return true;
0056 }
0057
0058 void arch_topdown_group_warn(void)
0059 {
0060     fprintf(stderr,
0061         "nmi_watchdog enabled with topdown. May give wrong results.\n"
0062         "Disable with echo 0 > /proc/sys/kernel/nmi_watchdog\n");
0063 }
0064
0065 #define TOPDOWN_SLOTS       0x0400
0066
0067 /*
0068  * Check whether a topdown group supports sample-read.
0069  *
0070  * Only Topdown metric supports sample-read. The slots
0071  * event must be the leader of the topdown group.
0072  */
0073
0074 bool arch_topdown_sample_read(struct evsel *leader)
0075 {
0076     if (!evsel__sys_has_perf_metrics(leader))
0077         return false;
0078
0079     if (leader->core.attr.config == TOPDOWN_SLOTS)
0080         return true;
0081
0082     return false;
0083 }
0084
0085 const char *arch_get_topdown_pmu_name(struct evlist *evlist, bool warn)
0086 {
0087     const char *pmu_name;
0088
0089     if (!perf_pmu__has_hybrid())
0090         return "cpu";
0091
0092     if (!evlist->hybrid_pmu_name) {
0093         if (warn)
0094             pr_warning("WARNING: default to use cpu_core topdown events\n");
0095         evlist->hybrid_pmu_name = perf_pmu__hybrid_type_to_pmu("core");
0096     }
0097
0098     pmu_name = evlist->hybrid_pmu_name;
0099
0100     return pmu_name;
0101 }
0102
0103 int topdown_parse_events(struct evlist *evlist)
0104 {
0105     const char *topdown_events;
0106     const char *pmu_name;
0107
0108     if (!topdown_sys_has_perf_metrics())
0109         return 0;
0110
0111     pmu_name = arch_get_topdown_pmu_name(evlist, false);
0112
0113     if (pmu_have_event(pmu_name, "topdown-heavy-ops")) {
0114         if (!strcmp(pmu_name, "cpu_core"))
0115             topdown_events = TOPDOWN_L2_EVENTS_CORE;
0116         else
0117             topdown_events = TOPDOWN_L2_EVENTS;
0118     } else {
0119         if (!strcmp(pmu_name, "cpu_core"))
0120             topdown_events = TOPDOWN_L1_EVENTS_CORE;
0121         else
0122             topdown_events = TOPDOWN_L1_EVENTS;
0123     }
0124
0125     return parse_event(evlist, topdown_events);
0126 }