Il 02/09/2014 21:57, Chris J Arges ha scritto:
> Seconds get from host: 1409687073
> Seconds get from kvmclock: 1409333034
> Offset: -354039
> offset too large!
> Check the stability of raw cycle ...
> Worst warp -354462672821748
> Total vcpus: 2
> Test loops: 10000000
> Total warps: 1
> Total stalls: 0
> Worst warp: -354462672821748
> Raw cycle is not stable
> Monotonic cycle test:
> Worst warp -354455286691490
Looks like one CPU is not being initialized correctly:
- The "next" correction in the trace is 18445647546048704244,
and (next-2^64) / -354039 is about 3.1*10^9. This is a pretty
plausible value of the TSC frequency. As a comparison, on my machine
I have next=18446366988261784997 and an uptime of 29:12 hours, and
the two match nicely with the CPU clock:
-(18446366988261784997-2^64) / (29.2 * 3600 * 10^9) = 3.587
$ grep -m1 model.name /proc/cpuinfo
model name : Intel(R) Xeon(R) CPU E5-1620 0 @ 3.60GHz
- The offset in seconds * 10^9 is pretty close to the warp in nanoseconds.
Can you: 1) try this patch 2) gather a new trace 3) include uptime and
cpuinfo in your report? All this without clocksource=hpet of course.
Thanks,
Paolo
diff --git a/x86/kvmclock_test.c b/x86/kvmclock_test.c
index 52a43fb..f68881c 100644
--- a/x86/kvmclock_test.c
+++ b/x86/kvmclock_test.c
@@ -7,6 +7,9 @@
#define DEFAULT_TEST_LOOPS 100000000L
#define DEFAULT_THRESHOLD 5L
+long threshold = DEFAULT_THRESHOLD;
+int nerr = 0;
+
struct test_info {
struct spinlock lock;
long loops; /* test loops */
@@ -20,8 +23,9 @@ struct test_info {
struct test_info ti[4];
-static int wallclock_test(long sec, long threshold)
+static void wallclock_test(void *p_sec)
{
+ long sec = *(long *)p_sec;
long ksec, offset;
struct timespec ts;
@@ -36,10 +40,8 @@ static int wallclock_test(long sec, long threshold)
if (offset > threshold || offset < -threshold) {
printf("offset too large!\n");
- return 1;
+ nerr++;
}
-
- return 0;
}
static void kvm_clock_test(void *data)
@@ -116,10 +118,9 @@ static int cycle_test(int ncpus, long loops, int check, struct test_info *ti)
int main(int ac, char **av)
{
int ncpus;
- int nerr = 0, i;
+ int i;
long loops = DEFAULT_TEST_LOOPS;
long sec = 0;
- long threshold = DEFAULT_THRESHOLD;
if (ac > 1)
loops = atol(av[1]);
@@ -137,7 +138,8 @@ int main(int ac, char **av)
on_cpu(i, kvm_clock_init, (void *)0);
if (ac > 2)
- nerr += wallclock_test(sec, threshold);
+ for (i = 0; i < ncpus; ++i)
+ on_cpu(i, wallclock_test, &sec);
printf("Check the stability of raw cycle ...\n");
pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT
--
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