1 /* 2 * Copyright 2014, Michael Ellerman, IBM Corp. 3 * Licensed under GPLv2. 4 */ 5 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <stdbool.h> 9 10 #include "ebb.h" 11 12 13 /* 14 * Test of counting cycles while using MMCR0_FC (freeze counters) to only count 15 * parts of the code. This is complicated by the fact that FC is set by the 16 * hardware when the event overflows. We may take the EBB after we have set FC, 17 * so we have to be careful about whether we clear FC at the end of the EBB 18 * handler or not. 19 */ 20 21 static bool counters_frozen = false; 22 static int ebbs_while_frozen = 0; 23 24 static void ebb_callee(void) 25 { 26 uint64_t mask, val; 27 28 mask = MMCR0_PMAO | MMCR0_FC; 29 30 val = mfspr(SPRN_BESCR); 31 if (!(val & BESCR_PMEO)) { 32 ebb_state.stats.spurious++; 33 goto out; 34 } 35 36 ebb_state.stats.ebb_count++; 37 trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count); 38 39 val = mfspr(SPRN_MMCR0); 40 trace_log_reg(ebb_state.trace, SPRN_MMCR0, val); 41 42 if (counters_frozen) { 43 trace_log_string(ebb_state.trace, "frozen"); 44 ebbs_while_frozen++; 45 mask &= ~MMCR0_FC; 46 } 47 48 count_pmc(1, sample_period); 49 out: 50 reset_ebb_with_clear_mask(mask); 51 } 52 53 int cycles_with_freeze(void) 54 { 55 struct event event; 56 uint64_t val; 57 bool fc_cleared; 58 59 event_init_named(&event, 0x1001e, "cycles"); 60 event_leader_ebb_init(&event); 61 62 event.attr.exclude_kernel = 1; 63 event.attr.exclude_hv = 1; 64 event.attr.exclude_idle = 1; 65 66 FAIL_IF(event_open(&event)); 67 68 setup_ebb_handler(ebb_callee); 69 ebb_global_enable(); 70 FAIL_IF(ebb_event_enable(&event)); 71 72 mtspr(SPRN_PMC1, pmc_sample_period(sample_period)); 73 74 fc_cleared = false; 75 76 /* Make sure we loop until we take at least one EBB */ 77 while ((ebb_state.stats.ebb_count < 20 && !fc_cleared) || 78 ebb_state.stats.ebb_count < 1) 79 { 80 counters_frozen = false; 81 mb(); 82 mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC); 83 84 FAIL_IF(core_busy_loop()); 85 86 counters_frozen = true; 87 mb(); 88 mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC); 89 90 val = mfspr(SPRN_MMCR0); 91 if (! (val & MMCR0_FC)) { 92 printf("Outside of loop, FC NOT set MMCR0 0x%lx\n", val); 93 fc_cleared = true; 94 } 95 } 96 97 ebb_global_disable(); 98 ebb_freeze_pmcs(); 99 100 count_pmc(1, sample_period); 101 102 dump_ebb_state(); 103 104 printf("EBBs while frozen %d\n", ebbs_while_frozen); 105 106 event_close(&event); 107 108 FAIL_IF(ebb_state.stats.ebb_count == 0); 109 FAIL_IF(fc_cleared); 110 111 return 0; 112 } 113 114 int main(void) 115 { 116 return test_harness(cycles_with_freeze, "cycles_with_freeze"); 117 } 118