[kvm-unit-tests PATCH 1/2] arm/arm64: gic: Add IPI latency test

[Jingyi Wang <wangjingyi11@xxxxxxxxxx>]

This patch add a test to measure the latency of IPI injection.

Signed-off-by: Jingyi Wang <wangjingyi11@xxxxxxxxxx>
---
 arm/gic.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arm/gic.c b/arm/gic.c
index fcf4c1f..f5e830e 100644
--- a/arm/gic.c
+++ b/arm/gic.c
@@ -27,6 +27,9 @@ struct gic {
 	struct {
 		void (*send_self)(void);
 		void (*send_broadcast)(void);
+		u64 ipi_inject_time;
+		u64 ipi_receive_time[NR_CPUS];
+		int nr_records;
 	} ipi;
 };
 
@@ -142,6 +145,7 @@ static void check_irqnr(u32 irqnr)
 
 static void ipi_handler(struct pt_regs *regs __unused)
 {
+	gic->ipi.ipi_receive_time[gic->ipi.nr_records++] = get_cntvct();
 	u32 irqstat = gic_read_iar();
 	u32 irqnr = gic_iar_irqnr(irqstat);
 
@@ -187,9 +191,16 @@ static void ipi_test_self(void)
 	stats_reset();
 	cpumask_clear(&mask);
 	cpumask_set_cpu(smp_processor_id(), &mask);
+
+	gic->ipi.nr_records = 0;
+	gic->ipi.ipi_inject_time = get_cntvct();
 	gic->ipi.send_self();
+
 	check_acked("IPI: self", &mask);
 	report_prefix_pop();
+
+	report_info("The latency of ipi_test_self: %ld cycles",
+			gic->ipi.ipi_receive_time[0] - gic->ipi.ipi_inject_time);
 }
 
 static void ipi_test_smp(void)
@@ -202,17 +213,33 @@ static void ipi_test_smp(void)
 	cpumask_copy(&mask, &cpu_present_mask);
 	for (i = smp_processor_id() & 1; i < nr_cpus; i += 2)
 		cpumask_clear_cpu(i, &mask);
+
+	gic->ipi.nr_records = 0;
+	gic->ipi.ipi_inject_time = get_cntvct();
 	gic_ipi_send_mask(IPI_IRQ, &mask);
+
 	check_acked("IPI: directed", &mask);
 	report_prefix_pop();
 
+	for (i = 0; i < gic->ipi.nr_records; i++)
+		report_info("The latency of ipi_test_smp(directed): %ld cycles",
+			gic->ipi.ipi_receive_time[i] - gic->ipi.ipi_inject_time);
+
 	report_prefix_push("broadcast");
 	stats_reset();
 	cpumask_copy(&mask, &cpu_present_mask);
 	cpumask_clear_cpu(smp_processor_id(), &mask);
+
+	gic->ipi.nr_records = 0;
+	gic->ipi.ipi_inject_time = get_cntvct();
 	gic->ipi.send_broadcast();
+
 	check_acked("IPI: broadcast", &mask);
 	report_prefix_pop();
+
+	for (i = 0; i < gic->ipi.nr_records; i++)
+		report_info("The latency of ipi_test_smp(broadcast): %ld cycles",
+			gic->ipi.ipi_receive_time[i] - gic->ipi.ipi_inject_time);
 }
 
 static void ipi_enable(void)
-- 
2.19.1