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/*
* 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");
}
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