[3/4] printk: Minimize time zero output

Commit Message

Mike Travis Feb. 25, 2011, 6:06 p.m. UTC

None

Patch

--- linux.orig/kernel/printk.c
+++ linux/kernel/printk.c
@@ -745,12 +745,17 @@  static inline int printk_emit_time(void)
 	char tbuf[50], *tp;
 	unsigned tlen;
 	unsigned long long t;
-	unsigned long microsec_rem;
 
 	t = cpu_clock(printk_cpu);
-	microsec_rem = do_div(t, 1000000000) / 1000;
-	tlen = sprintf(tbuf, "[%5lu.%06lu] ", (unsigned long)t, microsec_rem);
+	if (likely(t)) {
+		unsigned long microsec_rem = do_div(t, 1000000000) / 1000;
 
+		tlen = sprintf(tbuf, "[%5lu.%06lu] ",
+					(unsigned long)t, microsec_rem);
+	} else {
+		/* reduce byte count in log when time is zero */
+		tlen = sprintf(tbuf, "[0] ");
+	}
 	for (tp = tbuf; tp < tbuf + tlen; tp++)
 		emit_log_char(*tp);