kernel/tools/testing/selftests/powerpc/pmu/ebb/multi_ebb_procs_test.c

   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
  19 static bool child_should_exit;
  20
  21 static void sigint_handler(int signal)
  22 {
  23         child_should_exit = true;
  24 }
  25
  26 struct sigaction sigint_action = {
  27         .sa_handler = sigint_handler,
  28 };
  29
  30 static 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
  77 int 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
 108 int main(void)
 109 {
 110         return test_harness(multi_ebb_procs, "multi_ebb_procs");
 111 }