0135-initcall-only-print-non-zero-initcall-debug-to-speed.patch

From 496f1bc8c53f359a2fe07204d3c5ffdba963994e Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.king@intel.com>
Date: Fri, 20 Jan 2023 11:16:42 +0000
Subject: [PATCH] initcall: only print non-zero initcall debug to speed up boot

Printing initcall timings that successfully return after 0 usecs
provides not much useful information and takes a small amount of time
to do so. Disable the initcall timings for these specific cases. On
an Alderlake i9-12900 this reduces kernel boot time by 0.67% (timed
up to the invocation of systemd starting) based on 10 boot measurements.

Signed-off-by: Colin Ian King <colin.king@intel.com>
---
 init/main.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/init/main.c b/init/main.c
index aa21add5f7c5..715d57f58895 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1254,10 +1254,13 @@ static __init_or_module void
 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
 {
 	ktime_t rettime, *calltime = data;
+	long long delta;
 
 	rettime = ktime_get();
-	printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
-		 fn, ret, (unsigned long long)ktime_us_delta(rettime, *calltime));
+	delta = ktime_us_delta(rettime, *calltime);
+	if (ret || delta)
+		printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
+			fn, ret, (unsigned long long)ktime_us_delta(rettime, *calltime));
 }
 
 static ktime_t initcall_calltime;
-- 
2.39.1