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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/testing/selftests/powerpc/pmu/ebb/instruction_count_test.c | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/powerpc/pmu/ebb/instruction_count_test.c')
-rw-r--r-- | tools/testing/selftests/powerpc/pmu/ebb/instruction_count_test.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/pmu/ebb/instruction_count_test.c b/tools/testing/selftests/powerpc/pmu/ebb/instruction_count_test.c new file mode 100644 index 000000000..eed338b18 --- /dev/null +++ b/tools/testing/selftests/powerpc/pmu/ebb/instruction_count_test.c @@ -0,0 +1,167 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2014, Michael Ellerman, IBM Corp. + */ + +#define _GNU_SOURCE + +#include <stdio.h> +#include <stdbool.h> +#include <string.h> +#include <sys/prctl.h> + +#include "ebb.h" + + +/* + * Run a calibrated instruction loop and count instructions executed using + * EBBs. Make sure the counts look right. + */ + +extern void thirty_two_instruction_loop(uint64_t loops); + +static bool counters_frozen = true; + +static int do_count_loop(struct event *event, uint64_t instructions, + uint64_t overhead, bool report) +{ + int64_t difference, expected; + double percentage; + + clear_ebb_stats(); + + counters_frozen = false; + mb(); + mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC); + + thirty_two_instruction_loop(instructions >> 5); + + counters_frozen = true; + mb(); + mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC); + + count_pmc(4, sample_period); + + event->result.value = ebb_state.stats.pmc_count[4-1]; + expected = instructions + overhead; + difference = event->result.value - expected; + percentage = (double)difference / event->result.value * 100; + + if (report) { + printf("Looped for %lu instructions, overhead %lu\n", instructions, overhead); + printf("Expected %lu\n", expected); + printf("Actual %llu\n", event->result.value); + printf("Delta %ld, %f%%\n", difference, percentage); + printf("Took %d EBBs\n", ebb_state.stats.ebb_count); + } + + if (difference < 0) + difference = -difference; + + /* Tolerate a difference of up to 0.0001 % */ + difference *= 10000 * 100; + if (difference / event->result.value) + return -1; + + return 0; +} + +/* Count how many instructions it takes to do a null loop */ +static uint64_t determine_overhead(struct event *event) +{ + uint64_t current, overhead; + int i; + + do_count_loop(event, 0, 0, false); + overhead = event->result.value; + + for (i = 0; i < 100; i++) { + do_count_loop(event, 0, 0, false); + current = event->result.value; + if (current < overhead) { + printf("Replacing overhead %lu with %lu\n", overhead, current); + overhead = current; + } + } + + return overhead; +} + +static void pmc4_ebb_callee(void) +{ + uint64_t val; + + val = mfspr(SPRN_BESCR); + if (!(val & BESCR_PMEO)) { + ebb_state.stats.spurious++; + goto out; + } + + ebb_state.stats.ebb_count++; + count_pmc(4, sample_period); +out: + if (counters_frozen) + reset_ebb_with_clear_mask(MMCR0_PMAO); + else + reset_ebb(); +} + +int instruction_count(void) +{ + struct event event; + uint64_t overhead; + + SKIP_IF(!ebb_is_supported()); + + event_init_named(&event, 0x400FA, "PM_RUN_INST_CMPL"); + 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)); + FAIL_IF(ebb_event_enable(&event)); + + sample_period = COUNTER_OVERFLOW; + + setup_ebb_handler(pmc4_ebb_callee); + mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC); + ebb_global_enable(); + + overhead = determine_overhead(&event); + printf("Overhead of null loop: %lu instructions\n", overhead); + + /* Run for 1M instructions */ + FAIL_IF(do_count_loop(&event, 0x100000, overhead, true)); + + /* Run for 10M instructions */ + FAIL_IF(do_count_loop(&event, 0xa00000, overhead, true)); + + /* Run for 100M instructions */ + FAIL_IF(do_count_loop(&event, 0x6400000, overhead, true)); + + /* Run for 1G instructions */ + FAIL_IF(do_count_loop(&event, 0x40000000, overhead, true)); + + /* Run for 16G instructions */ + FAIL_IF(do_count_loop(&event, 0x400000000, overhead, true)); + + /* Run for 64G instructions */ + FAIL_IF(do_count_loop(&event, 0x1000000000, overhead, true)); + + /* Run for 128G instructions */ + FAIL_IF(do_count_loop(&event, 0x2000000000, overhead, true)); + + ebb_global_disable(); + event_close(&event); + + printf("Finished OK\n"); + + return 0; +} + +int main(void) +{ + test_harness_set_timeout(300); + return test_harness(instruction_count, "instruction_count"); +} |