This patch separates the timestamp code out from printk. Thus, other
components, like the statistics infrastructure, can also make use of it
and provide similar timestamps. It just makes sense to have one timestamp
format throughout the kernel.
The original piece of code was a bit promiscuous, IMHO.
Please accept the little cleanup that comes with my patch.
And I think that I have fixed a printed_len related miscalculation.
printed_len needs to be increased if no valid log level has been found
and a log level prefix has been added by printk(). Otherwise, printed_len
must not be increased. The old code did it the other way around (in the
timestamp case).
Signed-off-by: Martin Peschke <[email protected]>
---
include/linux/jiffies.h | 7 ++++
kernel/printk.c | 74 +++++++++++++++++++-----------------------------
2 files changed, 37 insertions(+), 44 deletions(-)
diff -Nurp a/include/linux/jiffies.h b/include/linux/jiffies.h
--- a/include/linux/jiffies.h 2006-05-19 15:44:27.000000000 +0200
+++ b/include/linux/jiffies.h 2006-05-19 16:01:58.000000000 +0200
@@ -447,4 +447,11 @@ static inline u64 nsec_to_clock_t(u64 x)
return x;
}
+static inline int nsec_to_timestamp(char *s, unsigned long long t)
+{
+ unsigned long nsec_rem = do_div(t, 1000000000);
+ return sprintf(s, "[%5lu.%06lu]", (unsigned long)t, nsec_rem/1000);
+}
+#define TIMESTAMP_SIZE 30
+
#endif
diff -Nurp a/kernel/printk.c b/kernel/printk.c
--- a/kernel/printk.c 2006-05-19 15:44:27.000000000 +0200
+++ b/kernel/printk.c 2006-05-19 16:01:58.000000000 +0200
@@ -493,7 +493,7 @@ asmlinkage int vprintk(const char *fmt,
int printed_len;
char *p;
static char printk_buf[1024];
- static int log_level_unknown = 1;
+ static int new_line = 1;
preempt_disable();
if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id())
@@ -510,59 +510,45 @@ asmlinkage int vprintk(const char *fmt,
/*
* Copy the output into log_buf. If the caller didn't provide
- * appropriate log level tags, we insert them here
+ * appropriate log level tags, we insert them here.
*/
for (p = printk_buf; *p; p++) {
- if (log_level_unknown) {
- /* log_level_unknown signals the start of a new line */
+ if (new_line) {
+ /* The log level token is first. */
+ int loglev_char;
+ if (p[0] == '<' && p[1] >='0' &&
+ p[1] <= '7' && p[2] == '>') {
+ loglev_char = p[1];
+ p += 3;
+ printed_len -= 3;
+ } else {
+ loglev_char = default_message_loglevel + '0';
+ }
+ emit_log_char('<');
+ emit_log_char(loglev_char);
+ emit_log_char('>');
+ /* A timestamp, if requested, goes next. */
if (printk_time) {
- int loglev_char;
- char tbuf[50], *tp;
- unsigned tlen;
- unsigned long long t;
- unsigned long nanosec_rem;
-
- /*
- * force the log level token to be
- * before the time output.
- */
- if (p[0] == '<' && p[1] >='0' &&
- p[1] <= '7' && p[2] == '>') {
- loglev_char = p[1];
- p += 3;
- printed_len -= 3;
- } else {
- loglev_char = default_message_loglevel
- + '0';
- }
- t = printk_clock();
- nanosec_rem = do_div(t, 1000000000);
- tlen = sprintf(tbuf,
- "<%c>[%5lu.%06lu] ",
- loglev_char,
- (unsigned long)t,
- nanosec_rem/1000);
-
- for (tp = tbuf; tp < tbuf + tlen; tp++)
+ char tbuf[TIMESTAMP_SIZE], *tp;
+ printed_len += nsec_to_timestamp(tbuf,
+ printk_clock());
+ for (tp = tbuf; *tp; tp++)
emit_log_char(*tp);
- printed_len += tlen;
- } else {
- if (p[0] != '<' || p[1] < '0' ||
- p[1] > '7' || p[2] != '>') {
- emit_log_char('<');
- emit_log_char(default_message_loglevel
- + '0');
- emit_log_char('>');
- printed_len += 3;
- }
+ emit_log_char(' ');
+ printed_len++;
}
- log_level_unknown = 0;
+ new_line = 0;
if (!*p)
break;
}
+ /*
+ * Once we are done with special strings at the head of
+ * each line, we just keep copying characters until
+ * we come across another line and need to start over.
+ */
emit_log_char(*p);
if (*p == '\n')
- log_level_unknown = 1;
+ new_line = 1;
}
if (!cpu_online(smp_processor_id())) {
On 5/19/06, Martin Peschke <[email protected]> wrote:
> This patch separates the timestamp code out from printk. Thus, other
> components, like the statistics infrastructure, can also make use of it
> and provide similar timestamps. It just makes sense to have one timestamp
> format throughout the kernel.
>
> The original piece of code was a bit promiscuous, IMHO.
> Please accept the little cleanup that comes with my patch.
>
> And I think that I have fixed a printed_len related miscalculation.
> printed_len needs to be increased if no valid log level has been found
> and a log level prefix has been added by printk(). Otherwise, printed_len
> must not be increased. The old code did it the other way around (in the
> timestamp case).
>
> Signed-off-by: Martin Peschke <[email protected]>
> ---
>
> include/linux/jiffies.h | 7 ++++
> kernel/printk.c | 74 +++++++++++++++++++-----------------------------
> 2 files changed, 37 insertions(+), 44 deletions(-)
>
> diff -Nurp a/include/linux/jiffies.h b/include/linux/jiffies.h
> --- a/include/linux/jiffies.h 2006-05-19 15:44:27.000000000 +0200
> +++ b/include/linux/jiffies.h 2006-05-19 16:01:58.000000000 +0200
> @@ -447,4 +447,11 @@ static inline u64 nsec_to_clock_t(u64 x)
> return x;
> }
>
> +static inline int nsec_to_timestamp(char *s, unsigned long long t)
> +{
> + unsigned long nsec_rem = do_div(t, 1000000000);
Could we please use NSEC_PER_SEC. I cannot count the number of zeros
after the 1.
> + return sprintf(s, "[%5lu.%06lu]", (unsigned long)t, nsec_rem/1000);
> +}
Something symbolic for the 1000 would be better. NSECS_PER_USEC probably?
> +#define TIMESTAMP_SIZE 30
> +
> #endif
> diff -Nurp a/kernel/printk.c b/kernel/printk.c
> --- a/kernel/printk.c 2006-05-19 15:44:27.000000000 +0200
> +++ b/kernel/printk.c 2006-05-19 16:01:58.000000000 +0200
> @@ -493,7 +493,7 @@ asmlinkage int vprintk(const char *fmt,
> int printed_len;
> char *p;
> static char printk_buf[1024];
> - static int log_level_unknown = 1;
> + static int new_line = 1;
>
> preempt_disable();
> if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id())
> @@ -510,59 +510,45 @@ asmlinkage int vprintk(const char *fmt,
>
> /*
> * Copy the output into log_buf. If the caller didn't provide
> - * appropriate log level tags, we insert them here
> + * appropriate log level tags, we insert them here.
> */
> for (p = printk_buf; *p; p++) {
> - if (log_level_unknown) {
> - /* log_level_unknown signals the start of a new line */
> + if (new_line) {
> + /* The log level token is first. */
> + int loglev_char;
> + if (p[0] == '<' && p[1] >='0' &&
> + p[1] <= '7' && p[2] == '>') {
> + loglev_char = p[1];
> + p += 3;
> + printed_len -= 3;
> + } else {
> + loglev_char = default_message_loglevel + '0';
> + }
> + emit_log_char('<');
> + emit_log_char(loglev_char);
> + emit_log_char('>');
> + /* A timestamp, if requested, goes next. */
> if (printk_time) {
> - int loglev_char;
> - char tbuf[50], *tp;
> - unsigned tlen;
> - unsigned long long t;
> - unsigned long nanosec_rem;
> -
> - /*
> - * force the log level token to be
> - * before the time output.
> - */
> - if (p[0] == '<' && p[1] >='0' &&
> - p[1] <= '7' && p[2] == '>') {
> - loglev_char = p[1];
> - p += 3;
> - printed_len -= 3;
> - } else {
> - loglev_char = default_message_loglevel
> - + '0';
> - }
> - t = printk_clock();
> - nanosec_rem = do_div(t, 1000000000);
> - tlen = sprintf(tbuf,
> - "<%c>[%5lu.%06lu] ",
> - loglev_char,
> - (unsigned long)t,
> - nanosec_rem/1000);
> -
> - for (tp = tbuf; tp < tbuf + tlen; tp++)
> + char tbuf[TIMESTAMP_SIZE], *tp;
> + printed_len += nsec_to_timestamp(tbuf,
> + printk_clock());
> + for (tp = tbuf; *tp; tp++)
> emit_log_char(*tp);
> - printed_len += tlen;
> - } else {
> - if (p[0] != '<' || p[1] < '0' ||
> - p[1] > '7' || p[2] != '>') {
> - emit_log_char('<');
> - emit_log_char(default_message_loglevel
> - + '0');
> - emit_log_char('>');
> - printed_len += 3;
> - }
> + emit_log_char(' ');
> + printed_len++;
> }
> - log_level_unknown = 0;
> + new_line = 0;
> if (!*p)
> break;
> }
> + /*
> + * Once we are done with special strings at the head of
> + * each line, we just keep copying characters until
> + * we come across another line and need to start over.
> + */
> emit_log_char(*p);
> if (*p == '\n')
> - log_level_unknown = 1;
> + new_line = 1;
> }
>
> if (!cpu_online(smp_processor_id())) {
>
>
> -
Regards,
Balbir
Linux Technology Center,
India Software Labs,
Bangalore
Balbir Singh wrote:
>> +static inline int nsec_to_timestamp(char *s, unsigned long long t)
>> +{
>> + unsigned long nsec_rem = do_div(t, 1000000000);
>
> Could we please use NSEC_PER_SEC. I cannot count the number of zeros
> after the 1.
Sure. I tried to keep my changes as small as possible ;-)
>> + return sprintf(s, "[%5lu.%06lu]", (unsigned long)t,
>> nsec_rem/1000);
>> +}
>
> Something symbolic for the 1000 would be better. NSECS_PER_USEC probably?
Makes sense.
Thanks,
Martin
Martin Peschke wrote:
> The original piece of code was a bit promiscuous, IMHO.
> Please accept the little cleanup that comes with my patch.
In general, I like the cleanup. See comments below.
> And I think that I have fixed a printed_len related miscalculation.
> printed_len needs to be increased if no valid log level has been found
> and a log level prefix has been added by printk(). Otherwise, printed_len
> must not be increased. The old code did it the other way around (in the
> timestamp case).
I'm not following your change here. I can't find the problem you
mention in the original code. And your fix appears to mess up the
printed_len.
> + if (new_line) {
> + /* The log level token is first. */
> + int loglev_char;
> + if (p[0] == '<' && p[1] >='0' &&
> + p[1] <= '7' && p[2] == '>') {
> + loglev_char = p[1];
> + p += 3;
> + printed_len -= 3;
Here you subtract from the printed_len to account for skipping
the submitted log level.
> + } else {
> + loglev_char = default_message_loglevel + '0';
> + }
> + emit_log_char('<');
> + emit_log_char(loglev_char);
> + emit_log_char('>');
But here you don't re-count the chars for the log-level
you are adding back in. There's a discrepancy here.
Please look at this again. NAK
-- Tim
=============================
Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Electronics
=============================