LXR linux/tools/testing/selftests/powerpc/pmu/ebb/multi_ebb_procs

   1/*
   2 * Copyright 2014, Michael Ellerman, IBM Corp.
   3 * Licensed under GPLv2.
   4 */
   5
   6#include <stdbool.h>
   7#include <stdio.h>
   8#include <stdlib.h>
   9#include <signal.h>
  10
  11#include "ebb.h"
  12
  13
  14/*
  15 * Test running multiple EBB using processes at once on a single CPU. They
  16 * should all run happily without interfering with each other.
  17 */
  18
  19static bool child_should_exit;
  20
  21static void sigint_handler(int signal)
  22{
  23        child_should_exit = true;
  24}
  25
  26struct sigaction sigint_action = {
  27        .sa_handler = sigint_handler,
  28};
  29
  30static int cycles_child(void)
  31{
  32        struct event event;
  33
  34        if (sigaction(SIGINT, &sigint_action, NULL)) {
  35                perror("sigaction");
  36                return 1;
  37        }
  38
  39        event_init_named(&event, 0x1001e, "cycles");
  40        event_leader_ebb_init(&event);
  41
  42        event.attr.exclude_kernel = 1;
  43        event.attr.exclude_hv = 1;
  44        event.attr.exclude_idle = 1;
  45
  46        FAIL_IF(event_open(&event));
  47
  48        ebb_enable_pmc_counting(1);
  49        setup_ebb_handler(standard_ebb_callee);
  50        ebb_global_enable();
  51
  52        FAIL_IF(ebb_event_enable(&event));
  53
  54        mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
  55
  56        while (!child_should_exit) {
  57                FAIL_IF(core_busy_loop());
  58                FAIL_IF(ebb_check_mmcr0());
  59        }
  60
  61        ebb_global_disable();
  62        ebb_freeze_pmcs();
  63
  64        count_pmc(1, sample_period);
  65
  66        dump_summary_ebb_state();
  67
  68        event_close(&event);
  69
  70        FAIL_IF(ebb_state.stats.ebb_count == 0);
  71
  72        return 0;
  73}
  74
  75#define NR_CHILDREN     4
  76
  77int multi_ebb_procs(void)
  78{
  79        pid_t pids[NR_CHILDREN];
  80        int cpu, rc, i;
  81
  82        SKIP_IF(!ebb_is_supported());
  83
  84        cpu = pick_online_cpu();
  85        FAIL_IF(cpu < 0);
  86        FAIL_IF(bind_to_cpu(cpu));
  87
  88        for (i = 0; i < NR_CHILDREN; i++) {
  89                pids[i] = fork();
  90                if (pids[i] == 0)
  91                        exit(cycles_child());
  92        }
  93
  94        /* Have them all run for "a while" */
  95        sleep(10);
  96
  97        rc = 0;
  98        for (i = 0; i < NR_CHILDREN; i++) {
  99                /* Tell them to stop */
 100                kill(pids[i], SIGINT);
 101                /* And wait */
 102                rc |= wait_for_child(pids[i]);
 103        }
 104
 105        return rc;
 106}
 107
 108int main(void)
 109{
 110        return test_harness(multi_ebb_procs, "multi_ebb_procs");
 111}
 112