[kvm-unit-tests,v3,10/10] arm64: microbench: Add timer_post() to get actual PPI latency

Commit Message

Jingyi Wang July 31, 2020, 7:42 a.m. UTC

For we get the time duration of (10msec timer + injection latency)
in timer_exec(), we substract the value of 10msec in timer_post()
to get the actual latency.

Signed-off-by: Jingyi Wang <[e-mail]>
---
 arm/micro-bench.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Patch

diff --git a/arm/micro-bench.c b/arm/micro-bench.c
index 4680ba4..315fc7c 100644
--- a/arm/micro-bench.c
+++ b/arm/micro-bench.c
@@ -254,6 +254,18 @@  static void timer_exec(void)
 	assert_msg(irq_received, "failed to receive PPI in time, but received %d successfully\n", received);
 }
 
+static void timer_post(uint64_t total_ticks, uint64_t ntimes, struct ns_time *total_ns)
+{
+	/*
+	 * We use a 10msec timer to test the latency of PPI,
+	 * so we substract the ticks of 10msec to get the
+	 * actual latency
+	 */
+
+	total_ticks -= ntimes * (cntfrq / 100);
+	ticks_to_ns_time(total_ticks, total_ns);
+}
+
 static void hvc_exec(void)
 {
 	asm volatile("mov w0, #0x4b000000; hvc #0" ::: "w0");
@@ -302,7 +314,7 @@  static struct exit_test tests[] = {
 	{"ipi",			ipi_prep,	ipi_exec,		NULL,		65536,		true},
 	{"ipi_hw",		ipi_hw_prep,	ipi_exec,		NULL,		65536,		true},
 	{"lpi",			lpi_prep,	lpi_exec,		NULL,		65536,		true},
-	{"timer_10ms",		timer_prep,	timer_exec,		NULL,		256,		true},
+	{"timer_10ms",		timer_prep,	timer_exec,		timer_post,	256,		true},
 };
 
 #define PS_PER_SEC (1000 * 1000 * 1000 * 1000UL)