[6/6] printk: Minimize time zero output

Commit Message

Mike Travis Jan. 19, 2011, 11:01 p.m. UTC

None

Patch

--- linux-2.6.32.orig/kernel/printk.c
+++ linux-2.6.32/kernel/printk.c
@@ -806,11 +806,14 @@  asmlinkage int vprintk(const char *fmt,
 				unsigned long nanosec_rem;
 
 				t = cpu_clock(printk_cpu);
-				nanosec_rem = do_div(t, 1000000000);
-				tlen = sprintf(tbuf, "[%5lu.%06lu] ",
+				if (likely(t)) {
+					nanosec_rem = do_div(t, 1000000000);
+					tlen = sprintf(tbuf, "[%5lu.%06lu] ",
 						(unsigned long) t,
 						nanosec_rem / 1000);
-
+				} else {
+					tlen = sprintf(tbuf, "[0] ");
+				}
 				for (tp = tbuf; tp < tbuf + tlen; tp++)
 					emit_log_char(*tp);
 				printed_len += tlen;