17481cad4SMichael Ellerman /*
27481cad4SMichael Ellerman * Copyright 2013, Michael Ellerman, IBM Corp.
37481cad4SMichael Ellerman * Licensed under GPLv2.
47481cad4SMichael Ellerman */
57481cad4SMichael Ellerman
67481cad4SMichael Ellerman #define _GNU_SOURCE
77481cad4SMichael Ellerman
87481cad4SMichael Ellerman #include <stdio.h>
97481cad4SMichael Ellerman #include <stdbool.h>
107481cad4SMichael Ellerman #include <string.h>
117481cad4SMichael Ellerman #include <sys/prctl.h>
127481cad4SMichael Ellerman
137481cad4SMichael Ellerman #include "event.h"
147481cad4SMichael Ellerman #include "utils.h"
157481cad4SMichael Ellerman #include "lib.h"
167481cad4SMichael Ellerman
177481cad4SMichael Ellerman extern void thirty_two_instruction_loop_with_ll_sc(u64 loops, u64 *ll_sc_target);
187481cad4SMichael Ellerman
setup_event(struct event * e,u64 config,int type,char * name)197481cad4SMichael Ellerman static void setup_event(struct event *e, u64 config, int type, char *name)
207481cad4SMichael Ellerman {
217481cad4SMichael Ellerman event_init_opts(e, config, type, name);
227481cad4SMichael Ellerman
237481cad4SMichael Ellerman e->attr.disabled = 1;
247481cad4SMichael Ellerman e->attr.exclude_kernel = 1;
257481cad4SMichael Ellerman e->attr.exclude_hv = 1;
267481cad4SMichael Ellerman e->attr.exclude_idle = 1;
277481cad4SMichael Ellerman }
287481cad4SMichael Ellerman
do_count_loop(struct event * events,u64 instructions,u64 overhead,bool report)297481cad4SMichael Ellerman static int do_count_loop(struct event *events, u64 instructions,
307481cad4SMichael Ellerman u64 overhead, bool report)
317481cad4SMichael Ellerman {
327481cad4SMichael Ellerman s64 difference, expected;
337481cad4SMichael Ellerman double percentage;
347481cad4SMichael Ellerman u64 dummy;
357481cad4SMichael Ellerman
367481cad4SMichael Ellerman prctl(PR_TASK_PERF_EVENTS_ENABLE);
377481cad4SMichael Ellerman
387481cad4SMichael Ellerman /* Run for 1M instructions */
397481cad4SMichael Ellerman thirty_two_instruction_loop_with_ll_sc(instructions >> 5, &dummy);
407481cad4SMichael Ellerman
417481cad4SMichael Ellerman prctl(PR_TASK_PERF_EVENTS_DISABLE);
427481cad4SMichael Ellerman
437481cad4SMichael Ellerman event_read(&events[0]);
447481cad4SMichael Ellerman event_read(&events[1]);
457481cad4SMichael Ellerman event_read(&events[2]);
467481cad4SMichael Ellerman
477481cad4SMichael Ellerman expected = instructions + overhead + (events[2].result.value * 10);
487481cad4SMichael Ellerman difference = events[0].result.value - expected;
497481cad4SMichael Ellerman percentage = (double)difference / events[0].result.value * 100;
507481cad4SMichael Ellerman
517481cad4SMichael Ellerman if (report) {
527481cad4SMichael Ellerman printf("-----\n");
537481cad4SMichael Ellerman event_report(&events[0]);
547481cad4SMichael Ellerman event_report(&events[1]);
557481cad4SMichael Ellerman event_report(&events[2]);
567481cad4SMichael Ellerman
577481cad4SMichael Ellerman printf("Looped for %llu instructions, overhead %llu\n", instructions, overhead);
587481cad4SMichael Ellerman printf("Expected %llu\n", expected);
597481cad4SMichael Ellerman printf("Actual %llu\n", events[0].result.value);
607481cad4SMichael Ellerman printf("Delta %lld, %f%%\n", difference, percentage);
617481cad4SMichael Ellerman }
627481cad4SMichael Ellerman
637481cad4SMichael Ellerman event_reset(&events[0]);
647481cad4SMichael Ellerman event_reset(&events[1]);
657481cad4SMichael Ellerman event_reset(&events[2]);
667481cad4SMichael Ellerman
677481cad4SMichael Ellerman if (difference < 0)
687481cad4SMichael Ellerman difference = -difference;
697481cad4SMichael Ellerman
707481cad4SMichael Ellerman /* Tolerate a difference below 0.0001 % */
717481cad4SMichael Ellerman difference *= 10000 * 100;
727481cad4SMichael Ellerman if (difference / events[0].result.value)
737481cad4SMichael Ellerman return -1;
747481cad4SMichael Ellerman
757481cad4SMichael Ellerman return 0;
767481cad4SMichael Ellerman }
777481cad4SMichael Ellerman
787481cad4SMichael Ellerman /* Count how many instructions it takes to do a null loop */
determine_overhead(struct event * events)797481cad4SMichael Ellerman static u64 determine_overhead(struct event *events)
807481cad4SMichael Ellerman {
817481cad4SMichael Ellerman u64 current, overhead;
827481cad4SMichael Ellerman int i;
837481cad4SMichael Ellerman
847481cad4SMichael Ellerman do_count_loop(events, 0, 0, false);
857481cad4SMichael Ellerman overhead = events[0].result.value;
867481cad4SMichael Ellerman
877481cad4SMichael Ellerman for (i = 0; i < 100; i++) {
887481cad4SMichael Ellerman do_count_loop(events, 0, 0, false);
897481cad4SMichael Ellerman current = events[0].result.value;
907481cad4SMichael Ellerman if (current < overhead) {
917481cad4SMichael Ellerman printf("Replacing overhead %llu with %llu\n", overhead, current);
927481cad4SMichael Ellerman overhead = current;
937481cad4SMichael Ellerman }
947481cad4SMichael Ellerman }
957481cad4SMichael Ellerman
967481cad4SMichael Ellerman return overhead;
977481cad4SMichael Ellerman }
987481cad4SMichael Ellerman
997481cad4SMichael Ellerman #define PM_MRK_STCX_FAIL 0x03e158
1007481cad4SMichael Ellerman #define PM_STCX_FAIL 0x01e058
1017481cad4SMichael Ellerman
test_body(void)1027481cad4SMichael Ellerman static int test_body(void)
1037481cad4SMichael Ellerman {
1047481cad4SMichael Ellerman struct event events[3];
1057481cad4SMichael Ellerman u64 overhead;
1067481cad4SMichael Ellerman
107*872d11bcSMichael Ellerman // The STCX_FAIL event we use works on Power8 or later
108*872d11bcSMichael Ellerman SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
109*872d11bcSMichael Ellerman
1107481cad4SMichael Ellerman setup_event(&events[0], PERF_COUNT_HW_INSTRUCTIONS, PERF_TYPE_HARDWARE, "instructions");
1117481cad4SMichael Ellerman setup_event(&events[1], PERF_COUNT_HW_CPU_CYCLES, PERF_TYPE_HARDWARE, "cycles");
1127481cad4SMichael Ellerman setup_event(&events[2], PM_STCX_FAIL, PERF_TYPE_RAW, "stcx_fail");
1137481cad4SMichael Ellerman
1147481cad4SMichael Ellerman if (event_open(&events[0])) {
1157481cad4SMichael Ellerman perror("perf_event_open");
1167481cad4SMichael Ellerman return -1;
1177481cad4SMichael Ellerman }
1187481cad4SMichael Ellerman
1197481cad4SMichael Ellerman if (event_open_with_group(&events[1], events[0].fd)) {
1207481cad4SMichael Ellerman perror("perf_event_open");
1217481cad4SMichael Ellerman return -1;
1227481cad4SMichael Ellerman }
1237481cad4SMichael Ellerman
1247481cad4SMichael Ellerman if (event_open_with_group(&events[2], events[0].fd)) {
1257481cad4SMichael Ellerman perror("perf_event_open");
1267481cad4SMichael Ellerman return -1;
1277481cad4SMichael Ellerman }
1287481cad4SMichael Ellerman
1297481cad4SMichael Ellerman overhead = determine_overhead(events);
1307481cad4SMichael Ellerman printf("Overhead of null loop: %llu instructions\n", overhead);
1317481cad4SMichael Ellerman
1327481cad4SMichael Ellerman /* Run for 1Mi instructions */
1337481cad4SMichael Ellerman FAIL_IF(do_count_loop(events, 1000000, overhead, true));
1347481cad4SMichael Ellerman
1357481cad4SMichael Ellerman /* Run for 10Mi instructions */
1367481cad4SMichael Ellerman FAIL_IF(do_count_loop(events, 10000000, overhead, true));
1377481cad4SMichael Ellerman
1387481cad4SMichael Ellerman /* Run for 100Mi instructions */
1397481cad4SMichael Ellerman FAIL_IF(do_count_loop(events, 100000000, overhead, true));
1407481cad4SMichael Ellerman
1417481cad4SMichael Ellerman /* Run for 1Bi instructions */
1427481cad4SMichael Ellerman FAIL_IF(do_count_loop(events, 1000000000, overhead, true));
1437481cad4SMichael Ellerman
1447481cad4SMichael Ellerman /* Run for 16Bi instructions */
1457481cad4SMichael Ellerman FAIL_IF(do_count_loop(events, 16000000000, overhead, true));
1467481cad4SMichael Ellerman
1477481cad4SMichael Ellerman /* Run for 64Bi instructions */
1487481cad4SMichael Ellerman FAIL_IF(do_count_loop(events, 64000000000, overhead, true));
1497481cad4SMichael Ellerman
1507481cad4SMichael Ellerman event_close(&events[0]);
1517481cad4SMichael Ellerman event_close(&events[1]);
1527481cad4SMichael Ellerman
1537481cad4SMichael Ellerman return 0;
1547481cad4SMichael Ellerman }
1557481cad4SMichael Ellerman
count_ll_sc(void)1567481cad4SMichael Ellerman static int count_ll_sc(void)
1577481cad4SMichael Ellerman {
1587481cad4SMichael Ellerman return eat_cpu(test_body);
1597481cad4SMichael Ellerman }
1607481cad4SMichael Ellerman
main(void)1617481cad4SMichael Ellerman int main(void)
1627481cad4SMichael Ellerman {
1637481cad4SMichael Ellerman return test_harness(count_ll_sc, "count_ll_sc");
1647481cad4SMichael Ellerman }
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