blob: a3bc4ea4fd1b1502c07e372a710e95a680de93e6 [file] [log] [blame] [edit]
/*
* qemu command line | grep latency | cut -f 2 -d ":" > latency
*
* In octave:
* load latency
* min(latency)
* max(latency)
* mean(latency)
* hist(latency, 50)
*/
/*
* for host tracing of breakmax option:
*
* # cd /sys/kernel/debug/tracing/
* # echo x86-tsc > trace_clock
* # echo "kvm_exit kvm_entry kvm_msr" > set_event
* # echo "sched_switch $extratracepoints" >> set_event
* # echo apic_timer_fn > set_ftrace_filter
* # echo "function" > current_tracer
*/
#include "libcflat.h"
#include "apic.h"
#include "vm.h"
#include "smp.h"
#include "desc.h"
#include "isr.h"
#include "msr.h"
static void test_lapic_existence(void)
{
u32 lvr;
lvr = apic_read(APIC_LVR);
printf("apic version: %x\n", lvr);
report((u16)lvr == 0x14, "apic existence");
}
#define TSC_DEADLINE_TIMER_VECTOR 0xef
static int tdt_count;
u64 exptime;
int delta;
#define TABLE_SIZE 10000
u64 table[TABLE_SIZE];
volatile int table_idx;
volatile int hitmax = 0;
int breakmax = 0;
static void tsc_deadline_timer_isr(isr_regs_t *regs)
{
u64 now = rdtsc();
++tdt_count;
if (table_idx < TABLE_SIZE && tdt_count > 1)
table[table_idx++] = now - exptime;
if (breakmax && tdt_count > 1 && (now - exptime) > breakmax) {
hitmax = 1;
apic_write(APIC_EOI, 0);
return;
}
exptime = now+delta;
wrmsr(MSR_IA32_TSCDEADLINE, now+delta);
apic_write(APIC_EOI, 0);
}
static void start_tsc_deadline_timer(void)
{
handle_irq(TSC_DEADLINE_TIMER_VECTOR, tsc_deadline_timer_isr);
irq_enable();
wrmsr(MSR_IA32_TSCDEADLINE, rdmsr(MSR_IA32_TSC)+delta);
asm volatile ("nop");
}
static int enable_tsc_deadline_timer(void)
{
uint32_t lvtt;
if (this_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) {
lvtt = APIC_LVT_TIMER_TSCDEADLINE | TSC_DEADLINE_TIMER_VECTOR;
apic_write(APIC_LVTT, lvtt);
start_tsc_deadline_timer();
return 1;
} else {
return 0;
}
}
static void test_tsc_deadline_timer(void)
{
if(enable_tsc_deadline_timer()) {
printf("tsc deadline timer enabled\n");
} else {
printf("tsc deadline timer not detected, aborting\n");
abort();
}
}
int main(int argc, char **argv)
{
int i, size;
setup_vm();
test_lapic_existence();
mask_pic_interrupts();
delta = argc <= 1 ? 200000 : atol(argv[1]);
size = argc <= 2 ? TABLE_SIZE : atol(argv[2]);
breakmax = argc <= 3 ? 0 : atol(argv[3]);
printf("breakmax=%d\n", breakmax);
test_tsc_deadline_timer();
irq_enable();
/* The condition might have triggered already, so check before HLT. */
while (!hitmax && table_idx < size)
asm volatile("hlt");
for (i = 0; i < table_idx; i++) {
if (hitmax && i == table_idx-1)
printf("hit max: %d < ", breakmax);
printf("latency: %" PRId64 "\n", table[i]);
}
return report_summary();
}