x86/util/evsel.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <stdio.h>
0003 #include <stdlib.h>
0004 #include "util/evsel.h"
0005 #include "util/env.h"
0006 #include "util/pmu.h"
0007 #include "linux/string.h"
0008 #include "evsel.h"
0009 #include "util/debug.h"
0010
0011 #define IBS_FETCH_L3MISSONLY   (1ULL << 59)
0012 #define IBS_OP_L3MISSONLY      (1ULL << 16)
0013
0014 void arch_evsel__set_sample_weight(struct evsel *evsel)
0015 {
0016     evsel__set_sample_bit(evsel, WEIGHT_STRUCT);
0017 }
0018
0019 void arch_evsel__fixup_new_cycles(struct perf_event_attr *attr)
0020 {
0021     struct perf_env env = { .total_mem = 0, } ;
0022
0023     if (!perf_env__cpuid(&env))
0024         return;
0025
0026     /*
0027      * On AMD, precise cycles event sampling internally uses IBS pmu.
0028      * But IBS does not have filtering capabilities and perf by default
0029      * sets exclude_guest = 1. This makes IBS pmu event init fail and
0030      * thus perf ends up doing non-precise sampling. Avoid it by clearing
0031      * exclude_guest.
0032      */
0033     if (env.cpuid && strstarts(env.cpuid, "AuthenticAMD"))
0034         attr->exclude_guest = 0;
0035
0036     free(env.cpuid);
0037 }
0038
0039 /* Check whether the evsel's PMU supports the perf metrics */
0040 bool evsel__sys_has_perf_metrics(const struct evsel *evsel)
0041 {
0042     const char *pmu_name = evsel->pmu_name ? evsel->pmu_name : "cpu";
0043
0044     /*
0045      * The PERF_TYPE_RAW type is the core PMU type, e.g., "cpu" PMU
0046      * on a non-hybrid machine, "cpu_core" PMU on a hybrid machine.
0047      * The slots event is only available for the core PMU, which
0048      * supports the perf metrics feature.
0049      * Checking both the PERF_TYPE_RAW type and the slots event
0050      * should be good enough to detect the perf metrics feature.
0051      */
0052     if ((evsel->core.attr.type == PERF_TYPE_RAW) &&
0053         pmu_have_event(pmu_name, "slots"))
0054         return true;
0055
0056     return false;
0057 }
0058
0059 bool arch_evsel__must_be_in_group(const struct evsel *evsel)
0060 {
0061     if (!evsel__sys_has_perf_metrics(evsel))
0062         return false;
0063
0064     return evsel->name &&
0065         (strcasestr(evsel->name, "slots") ||
0066          strcasestr(evsel->name, "topdown"));
0067 }
0068
0069 int arch_evsel__hw_name(struct evsel *evsel, char *bf, size_t size)
0070 {
0071     u64 event = evsel->core.attr.config & PERF_HW_EVENT_MASK;
0072     u64 pmu = evsel->core.attr.config >> PERF_PMU_TYPE_SHIFT;
0073     const char *event_name;
0074
0075     if (event < PERF_COUNT_HW_MAX && evsel__hw_names[event])
0076         event_name = evsel__hw_names[event];
0077     else
0078         event_name = "unknown-hardware";
0079
0080     /* The PMU type is not required for the non-hybrid platform. */
0081     if (!pmu)
0082         return  scnprintf(bf, size, "%s", event_name);
0083
0084     return scnprintf(bf, size, "%s/%s/",
0085              evsel->pmu_name ? evsel->pmu_name : "cpu",
0086              event_name);
0087 }
0088
0089 static void ibs_l3miss_warn(void)
0090 {
0091     pr_warning(
0092 "WARNING: Hw internally resets sampling period when L3 Miss Filtering is enabled\n"
0093 "and tagged operation does not cause L3 Miss. This causes sampling period skew.\n");
0094 }
0095
0096 void arch__post_evsel_config(struct evsel *evsel, struct perf_event_attr *attr)
0097 {
0098     struct perf_pmu *evsel_pmu, *ibs_fetch_pmu, *ibs_op_pmu;
0099     static int warned_once;
0100     /* 0: Uninitialized, 1: Yes, -1: No */
0101     static int is_amd;
0102
0103     if (warned_once || is_amd == -1)
0104         return;
0105
0106     if (!is_amd) {
0107         struct perf_env *env = evsel__env(evsel);
0108
0109         if (!perf_env__cpuid(env) || !env->cpuid ||
0110             !strstarts(env->cpuid, "AuthenticAMD")) {
0111             is_amd = -1;
0112             return;
0113         }
0114         is_amd = 1;
0115     }
0116
0117     evsel_pmu = evsel__find_pmu(evsel);
0118     if (!evsel_pmu)
0119         return;
0120
0121     ibs_fetch_pmu = perf_pmu__find("ibs_fetch");
0122     ibs_op_pmu = perf_pmu__find("ibs_op");
0123
0124     if (ibs_fetch_pmu && ibs_fetch_pmu->type == evsel_pmu->type) {
0125         if (attr->config & IBS_FETCH_L3MISSONLY) {
0126             ibs_l3miss_warn();
0127             warned_once = 1;
0128         }
0129     } else if (ibs_op_pmu && ibs_op_pmu->type == evsel_pmu->type) {
0130         if (attr->config & IBS_OP_L3MISSONLY) {
0131             ibs_l3miss_warn();
0132             warned_once = 1;
0133         }
0134     }
0135 }