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Date: Tue, 18 Sep 2012 16:25:09 +0300
From: Andriy Gapon <avg@FreeBSD.org>
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Subject: cpu_spinwait in cngetc
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(Why[*]) Would anyone object to a change like this?

diff --git a/sys/kern/kern_cons.c b/sys/kern/kern_cons.c
index 5346bc3..d17846a 100644
--- a/sys/kern/kern_cons.c
+++ b/sys/kern/kern_cons.c
@@ -384,7 +384,7 @@ cngetc(void)
 	if (cn_mute)
 		return (-1);
 	while ((c = cncheckc()) == -1)
-		;
+		cpu_spinwait();
 	if (c == '\r')
 		c = '\n';		/* console input is always ICRNL */
 	return (c);

[*] :-)
-- 
Andriy Gapon