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

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