[PATCH 5/6] printk: Minimize time zero output

Mike Travis
2011-02-19T02:47:10Z

[-- Attachment #1: minimize-time-zero-msgs --]
[-- Type: text/plain, Size: 938 bytes --]

Reduce the length for time zero messages by only printing "[0] ".

v2: updated to apply to x86-tip

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Jack Steiner <steiner@sgi.com>
Reviewed-by: Robin Holt <holt@sgi.com>
---
kernel/printk.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

--- linux.orig/kernel/printk.c
+++ linux/kernel/printk.c
@@ -735,9 +735,14 @@ static inline int printk_emit_time(void)
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)) {
+ 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);

--