LXR linux/tools/perf/arch/x86/tests/intel-cqm.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include "tests/tests.h"
   3#include "perf.h"
   4#include "cloexec.h"
   5#include "debug.h"
   6#include "evlist.h"
   7#include "evsel.h"
   8#include "arch-tests.h"
   9#include "util.h"
  10
  11#include <signal.h>
  12#include <sys/mman.h>
  13#include <sys/wait.h>
  14#include <errno.h>
  15#include <string.h>
  16
  17static pid_t spawn(void)
  18{
  19        pid_t pid;
  20
  21        pid = fork();
  22        if (pid)
  23                return pid;
  24
  25        while(1)
  26                sleep(5);
  27        return 0;
  28}
  29
  30/*
  31 * Create an event group that contains both a sampled hardware
  32 * (cpu-cycles) and software (intel_cqm/llc_occupancy/) event. We then
  33 * wait for the hardware perf counter to overflow and generate a PMI,
  34 * which triggers an event read for both of the events in the group.
  35 *
  36 * Since reading Intel CQM event counters requires sending SMP IPIs, the
  37 * CQM pmu needs to handle the above situation gracefully, and return
  38 * the last read counter value to avoid triggering a WARN_ON_ONCE() in
  39 * smp_call_function_many() caused by sending IPIs from NMI context.
  40 */
  41int test__intel_cqm_count_nmi_context(struct test *test __maybe_unused, int subtest __maybe_unused)
  42{
  43        struct perf_evlist *evlist = NULL;
  44        struct perf_evsel *evsel = NULL;
  45        struct perf_event_attr pe;
  46        int i, fd[2], flag, ret;
  47        size_t mmap_len;
  48        void *event;
  49        pid_t pid;
  50        int err = TEST_FAIL;
  51
  52        flag = perf_event_open_cloexec_flag();
  53
  54        evlist = perf_evlist__new();
  55        if (!evlist) {
  56                pr_debug("perf_evlist__new failed\n");
  57                return TEST_FAIL;
  58        }
  59
  60        ret = parse_events(evlist, "intel_cqm/llc_occupancy/", NULL);
  61        if (ret) {
  62                pr_debug("parse_events failed, is \"intel_cqm/llc_occupancy/\" available?\n");
  63                err = TEST_SKIP;
  64                goto out;
  65        }
  66
  67        evsel = perf_evlist__first(evlist);
  68        if (!evsel) {
  69                pr_debug("perf_evlist__first failed\n");
  70                goto out;
  71        }
  72
  73        memset(&pe, 0, sizeof(pe));
  74        pe.size = sizeof(pe);
  75
  76        pe.type = PERF_TYPE_HARDWARE;
  77        pe.config = PERF_COUNT_HW_CPU_CYCLES;
  78        pe.read_format = PERF_FORMAT_GROUP;
  79
  80        pe.sample_period = 128;
  81        pe.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_READ;
  82
  83        pid = spawn();
  84
  85        fd[0] = sys_perf_event_open(&pe, pid, -1, -1, flag);
  86        if (fd[0] < 0) {
  87                pr_debug("failed to open event\n");
  88                goto out;
  89        }
  90
  91        memset(&pe, 0, sizeof(pe));
  92        pe.size = sizeof(pe);
  93
  94        pe.type = evsel->attr.type;
  95        pe.config = evsel->attr.config;
  96
  97        fd[1] = sys_perf_event_open(&pe, pid, -1, fd[0], flag);
  98        if (fd[1] < 0) {
  99                pr_debug("failed to open event\n");
 100                goto out;
 101        }
 102
 103        /*
 104         * Pick a power-of-two number of pages + 1 for the meta-data
 105         * page (struct perf_event_mmap_page). See tools/perf/design.txt.
 106         */
 107        mmap_len = page_size * 65;
 108
 109        event = mmap(NULL, mmap_len, PROT_READ, MAP_SHARED, fd[0], 0);
 110        if (event == (void *)(-1)) {
 111                pr_debug("failed to mmap %d\n", errno);
 112                goto out;
 113        }
 114
 115        sleep(1);
 116
 117        err = TEST_OK;
 118
 119        munmap(event, mmap_len);
 120
 121        for (i = 0; i < 2; i++)
 122                close(fd[i]);
 123
 124        kill(pid, SIGKILL);
 125        wait(NULL);
 126out:
 127        perf_evlist__delete(evlist);
 128        return err;
 129}
 130