From: David Woodhouse <dwmw@amazon.co.uk>
Date: Thu, 9 Dec 2021 14:20:23 +0000 (+0000)
Subject: Print bringup timing
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=323883ff23424dd3fc4697b1e934f0814a74f171;p=users%2Fdwmw2%2Flinux.git

Print bringup timing

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 5a8f1a93b57c3..305b2b109a43d 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1506,6 +1506,7 @@ void bringup_nonboot_cpus(unsigned int setup_max_cpus)
 {
 	unsigned int cpu;
 	int n = setup_max_cpus - num_online_cpus();
+	cycles_t t1, t2;
 
 	/* ∀ parallel pre-bringup state, bring N CPUs to it */
 	if (n > 0) {
@@ -1514,22 +1515,29 @@ void bringup_nonboot_cpus(unsigned int setup_max_cpus)
 		while (st <= CPUHP_BP_PARALLEL_DYN_END &&
 		       cpuhp_hp_states[st].name) {
 			int i = n;
-
+			t1 = get_cycles();
 			for_each_present_cpu(cpu) {
 				cpu_up(cpu, st);
 				if (!--i)
 					break;
 			}
+			t2 = get_cycles();
+
+			printk("Brought %d CPUs to %s in %lld cycles\n", n - i,
+			       cpuhp_hp_states[st].name, t2 - t1);
 			st++;
 		}
 	}
 
+	t1 = get_cycles();
 	for_each_present_cpu(cpu) {
 		if (num_online_cpus() >= setup_max_cpus)
 			break;
 		if (!cpu_online(cpu))
 			cpu_up(cpu, CPUHP_ONLINE);
 	}
+	t2 = get_cycles();
+	printk("Brought CPUs online in %lld cycles\n", t2 - t1);
 }
 
 #ifdef CONFIG_PM_SLEEP_SMP