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167 lines
3.7 KiB
167 lines
3.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright 2014, Michael Ellerman, IBM Corp. |
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*/ |
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#define _GNU_SOURCE |
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#include <stdio.h> |
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#include <stdbool.h> |
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#include <string.h> |
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#include <sys/prctl.h> |
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#include "ebb.h" |
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/* |
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* Run a calibrated instruction loop and count instructions executed using |
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* EBBs. Make sure the counts look right. |
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*/ |
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extern void thirty_two_instruction_loop(uint64_t loops); |
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static bool counters_frozen = true; |
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static int do_count_loop(struct event *event, uint64_t instructions, |
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uint64_t overhead, bool report) |
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{ |
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int64_t difference, expected; |
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double percentage; |
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clear_ebb_stats(); |
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counters_frozen = false; |
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mb(); |
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mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC); |
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thirty_two_instruction_loop(instructions >> 5); |
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counters_frozen = true; |
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mb(); |
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mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC); |
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count_pmc(4, sample_period); |
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event->result.value = ebb_state.stats.pmc_count[4-1]; |
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expected = instructions + overhead; |
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difference = event->result.value - expected; |
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percentage = (double)difference / event->result.value * 100; |
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if (report) { |
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printf("Looped for %lu instructions, overhead %lu\n", instructions, overhead); |
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printf("Expected %lu\n", expected); |
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printf("Actual %llu\n", event->result.value); |
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printf("Delta %ld, %f%%\n", difference, percentage); |
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printf("Took %d EBBs\n", ebb_state.stats.ebb_count); |
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} |
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if (difference < 0) |
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difference = -difference; |
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/* Tolerate a difference of up to 0.0001 % */ |
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difference *= 10000 * 100; |
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if (difference / event->result.value) |
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return -1; |
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return 0; |
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} |
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/* Count how many instructions it takes to do a null loop */ |
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static uint64_t determine_overhead(struct event *event) |
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{ |
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uint64_t current, overhead; |
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int i; |
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do_count_loop(event, 0, 0, false); |
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overhead = event->result.value; |
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for (i = 0; i < 100; i++) { |
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do_count_loop(event, 0, 0, false); |
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current = event->result.value; |
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if (current < overhead) { |
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printf("Replacing overhead %lu with %lu\n", overhead, current); |
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overhead = current; |
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} |
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} |
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return overhead; |
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} |
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static void pmc4_ebb_callee(void) |
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{ |
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uint64_t val; |
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val = mfspr(SPRN_BESCR); |
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if (!(val & BESCR_PMEO)) { |
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ebb_state.stats.spurious++; |
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goto out; |
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} |
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ebb_state.stats.ebb_count++; |
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count_pmc(4, sample_period); |
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out: |
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if (counters_frozen) |
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reset_ebb_with_clear_mask(MMCR0_PMAO); |
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else |
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reset_ebb(); |
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} |
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int instruction_count(void) |
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{ |
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struct event event; |
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uint64_t overhead; |
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SKIP_IF(!ebb_is_supported()); |
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event_init_named(&event, 0x400FA, "PM_RUN_INST_CMPL"); |
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event_leader_ebb_init(&event); |
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event.attr.exclude_kernel = 1; |
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event.attr.exclude_hv = 1; |
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event.attr.exclude_idle = 1; |
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FAIL_IF(event_open(&event)); |
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FAIL_IF(ebb_event_enable(&event)); |
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sample_period = COUNTER_OVERFLOW; |
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setup_ebb_handler(pmc4_ebb_callee); |
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mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC); |
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ebb_global_enable(); |
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overhead = determine_overhead(&event); |
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printf("Overhead of null loop: %lu instructions\n", overhead); |
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/* Run for 1M instructions */ |
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FAIL_IF(do_count_loop(&event, 0x100000, overhead, true)); |
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/* Run for 10M instructions */ |
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FAIL_IF(do_count_loop(&event, 0xa00000, overhead, true)); |
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/* Run for 100M instructions */ |
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FAIL_IF(do_count_loop(&event, 0x6400000, overhead, true)); |
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/* Run for 1G instructions */ |
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FAIL_IF(do_count_loop(&event, 0x40000000, overhead, true)); |
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/* Run for 16G instructions */ |
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FAIL_IF(do_count_loop(&event, 0x400000000, overhead, true)); |
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/* Run for 64G instructions */ |
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FAIL_IF(do_count_loop(&event, 0x1000000000, overhead, true)); |
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/* Run for 128G instructions */ |
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FAIL_IF(do_count_loop(&event, 0x2000000000, overhead, true)); |
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ebb_global_disable(); |
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event_close(&event); |
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printf("Finished OK\n"); |
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return 0; |
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} |
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int main(void) |
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{ |
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test_harness_set_timeout(300); |
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return test_harness(instruction_count, "instruction_count"); |
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}
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