diff options
Diffstat (limited to 'kernel/tools/testing/selftests/powerpc/pmu/ebb/cycles_with_freeze_test.c')
-rw-r--r-- | kernel/tools/testing/selftests/powerpc/pmu/ebb/cycles_with_freeze_test.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/kernel/tools/testing/selftests/powerpc/pmu/ebb/cycles_with_freeze_test.c b/kernel/tools/testing/selftests/powerpc/pmu/ebb/cycles_with_freeze_test.c new file mode 100644 index 000000000..754b3f200 --- /dev/null +++ b/kernel/tools/testing/selftests/powerpc/pmu/ebb/cycles_with_freeze_test.c @@ -0,0 +1,117 @@ +/* + * Copyright 2014, Michael Ellerman, IBM Corp. + * Licensed under GPLv2. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <stdbool.h> + +#include "ebb.h" + + +/* + * Test of counting cycles while using MMCR0_FC (freeze counters) to only count + * parts of the code. This is complicated by the fact that FC is set by the + * hardware when the event overflows. We may take the EBB after we have set FC, + * so we have to be careful about whether we clear FC at the end of the EBB + * handler or not. + */ + +static bool counters_frozen = false; +static int ebbs_while_frozen = 0; + +static void ebb_callee(void) +{ + uint64_t mask, val; + + mask = MMCR0_PMAO | MMCR0_FC; + + val = mfspr(SPRN_BESCR); + if (!(val & BESCR_PMEO)) { + ebb_state.stats.spurious++; + goto out; + } + + ebb_state.stats.ebb_count++; + trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count); + + val = mfspr(SPRN_MMCR0); + trace_log_reg(ebb_state.trace, SPRN_MMCR0, val); + + if (counters_frozen) { + trace_log_string(ebb_state.trace, "frozen"); + ebbs_while_frozen++; + mask &= ~MMCR0_FC; + } + + count_pmc(1, sample_period); +out: + reset_ebb_with_clear_mask(mask); +} + +int cycles_with_freeze(void) +{ + struct event event; + uint64_t val; + bool fc_cleared; + + event_init_named(&event, 0x1001e, "cycles"); + event_leader_ebb_init(&event); + + event.attr.exclude_kernel = 1; + event.attr.exclude_hv = 1; + event.attr.exclude_idle = 1; + + FAIL_IF(event_open(&event)); + + setup_ebb_handler(ebb_callee); + ebb_global_enable(); + FAIL_IF(ebb_event_enable(&event)); + + mtspr(SPRN_PMC1, pmc_sample_period(sample_period)); + + fc_cleared = false; + + /* Make sure we loop until we take at least one EBB */ + while ((ebb_state.stats.ebb_count < 20 && !fc_cleared) || + ebb_state.stats.ebb_count < 1) + { + counters_frozen = false; + mb(); + mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC); + + FAIL_IF(core_busy_loop()); + + counters_frozen = true; + mb(); + mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC); + + val = mfspr(SPRN_MMCR0); + if (! (val & MMCR0_FC)) { + printf("Outside of loop, FC NOT set MMCR0 0x%lx\n", val); + fc_cleared = true; + } + } + + ebb_global_disable(); + ebb_freeze_pmcs(); + + count_pmc(1, sample_period); + + dump_ebb_state(); + + printf("EBBs while frozen %d\n", ebbs_while_frozen); + + event_close(&event); + + FAIL_IF(ebb_state.stats.ebb_count == 0); + FAIL_IF(fc_cleared); + + return 0; +} + +int main(void) +{ + return test_harness(cycles_with_freeze, "cycles_with_freeze"); +} |