From: Avi Kivity <avi@xxxxxxxxxx>
This test round-robins executions among all cpus. If overcommitted, it will
execute at the rate the host switches vcpu contexts.
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
diff --git a/x86/vmexit.c b/x86/vmexit.c
index 31858ea..875caa3 100644
--- a/x86/vmexit.c
+++ b/x86/vmexit.c
@@ -12,6 +12,8 @@ static unsigned int inl(unsigned short port)
#define GOAL (1ull << 30)
+static int nr_cpus;
+
#ifdef __x86_64__
# define R "r"
#else
@@ -79,6 +81,27 @@ static void inl_pmtimer(void)
inl(0xb008);
}
+static void ple_round_robin(void)
+{
+ struct counter {
+ volatile int n1;
+ int n2;
+ } __attribute__((aligned(64)));
+ static struct counter counters[64] = { { -1, 0 } };
+ int me = smp_id();
+ int you;
+ volatile struct counter *p = &counters[me];
+
+ while (p->n1 == p->n2)
+ asm volatile ("pause");
+
+ p->n2 = p->n1;
+ you = me + 1;
+ if (you == nr_cpus)
+ you = 0;
+ ++counters[you].n1;
+}
+
static struct test {
void (*func)(void);
const char *name;
@@ -94,6 +117,7 @@ static struct test {
{ inl_pmtimer, "inl_from_pmtimer", .parallel = 1, },
{ ipi, "ipi", is_smp, .parallel = 0, },
{ ipi_halt, "ipi+halt", is_smp, .parallel = 0, },
+ { ple_round_robin, "ple-round-robin", .parallel = 1 },
};
unsigned iterations;
@@ -167,6 +191,7 @@ int main(int ac, char **av)
int i;
smp_init();
+ nr_cpus = cpu_count();
for (i = cpu_count(); i > 0; i--)
on_cpu(i-1, enable_nx, 0);
--
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