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