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Subject[PATCH 2.6.13-rc2-mm1] printk: add features when CONFIG_PRINTK_TIME=y
Date
Add 2 values which control time printing when CONFIG_PRINTK_TIME=y. Values can 
be changed on boot option printk_time=n,m or by /proc/sys/kernel/printk_time.
First one tell about what is printing: 0 - no additional time info, 1 - current time, 2 - difference between to consecutive printk calls. Second tell about
resolution of printing time.

Signed-off-by: Stanislaw W. Gruszka <stf_xl@wp.pl>

include/linux/sysctl.h | 1
kernel/printk.c | 119 ++++++++++++++++++++++++++++++++++++++-----------
kernel/sysctl.c | 14 +++++
3 files changed, 109 insertions(+), 25 deletions(-)

diff -uprN -X dontdiff linux-2.6.13-rc2.orig/include/linux/sysctl.h linux-2.6.13-rc2/include/linux/sysctl.h
--- linux-2.6.13-rc2.orig/include/linux/sysctl.h 2005-07-08 14:18:53.000000000 +0200
+++ linux-2.6.13-rc2/include/linux/sysctl.h 2005-07-10 00:46:53.000000000 +0200
@@ -137,6 +137,7 @@ enum
KERN_BOOTLOADER_TYPE=67, /* int: boot loader type */
KERN_RANDOMIZE=68, /* int: randomize virtual address space */
KERN_SETUID_DUMPABLE=69, /* int: behaviour of dumps for setuid core */
+ KERN_PRINTK_TIME=70, /* int: behaviour of printk time */
};


diff -uprN -X dontdiff linux-2.6.13-rc2.orig/kernel/printk.c linux-2.6.13-rc2/kernel/printk.c
--- linux-2.6.13-rc2.orig/kernel/printk.c 2005-07-08 14:18:54.000000000 +0200
+++ linux-2.6.13-rc2/kernel/printk.c 2005-07-10 00:48:20.000000000 +0200
@@ -472,21 +472,103 @@ static void zap_locks(void)
init_MUTEX(&console_sem);
}

-#if defined(CONFIG_PRINTK_TIME)
-static int printk_time = 1;
-#else
-static int printk_time = 0;
-#endif
+#ifdef CONFIG_PRINTK_TIME
+
+int printk_time_parm[2] = {
+ 1, /* 0 - no additional time info
+ * 1 - current time
+ * 2 - difference between to consecutive printk calls
+ */
+ 6 /* number of digits after dot
+ * proper values: 1,...,9
+ */
+};
+
+#define printk_time (printk_time_parm[0])
+#define printk_time_resolution (printk_time_parm[1])

static int __init printk_time_setup(char *str)
{
- if (*str)
- return 0;
- printk_time = 1;
+ int i, ints[3];
+
+ get_options(str, 3, ints);
+ for (i = 1; i <= ints[0]; i++)
+ printk_time_parm[i - 1] = ints[i];
+
return 1;
}

-__setup("time", printk_time_setup);
+__setup("printk_time=", printk_time_setup);
+
+static unsigned long long diff_time_start;
+static unsigned long long diff_time_end;
+
+#define SET_DIFF_TIME_START() \
+ diff_time_start = sched_clock()
+#define SET_DIFF_TIME_END() \
+ diff_time_end = sched_clock()
+
+/* base to the power of exp */
+static unsigned long simple_pow(unsigned long base, unsigned exp)
+{
+ unsigned long res = 1;
+
+ while (exp) {
+ if (exp % 2)
+ res *= base;
+ exp /= 2;
+ base *= base;
+ }
+
+ return res;
+}
+
+static int time_print(char loglev_char)
+{
+ char tbuf[50], *tp;
+ char *fmt = "<%c>[%5lu.%09lu] ";
+ unsigned tlen;
+ int res, opt;
+ unsigned long long time;
+ unsigned long nanosec_rem, resolution_rem;
+
+ res = printk_time_resolution;
+ if (res < 1)
+ res = 1;
+ if (res > 9)
+ res = 9;
+ fmt[12] = res + '0';
+
+ opt = printk_time;
+ if (opt == 1)
+ time = sched_clock();
+ else if (opt == 2)
+ time = diff_time_end - diff_time_start;
+ else
+ time = 0;
+
+ nanosec_rem = do_div(time, 1000000000);
+ resolution_rem = nanosec_rem / simple_pow(10, 9 - res);
+ tlen = snprintf(tbuf, sizeof(tbuf), fmt, loglev_char,
+ (unsigned long) time, resolution_rem);
+
+ for (tp = tbuf; tp < tbuf + tlen; tp++)
+ emit_log_char(*tp);
+
+ return tlen - 3;
+}
+
+#else // CONFIG_PRINTK_TIME
+
+#define SET_DIFF_TIME_START() do { } while (0)
+#define SET_DIFF_TIME_END() do { } while (0)
+
+#define printk_time 0
+#define printk_time_resolution 0
+#define time_print(x) 0
+
+#endif // CONFIG_PRINTK_TIME
+

/*
* This is printk. It can be called from any context. We want it to work.
@@ -507,9 +589,11 @@ asmlinkage int printk(const char *fmt, .
va_list args;
int r;

+ SET_DIFF_TIME_END();
va_start(args, fmt);
r = vprintk(fmt, args);
va_end(args);
+ SET_DIFF_TIME_START();

return r;
}
@@ -540,11 +624,6 @@ asmlinkage int vprintk(const char *fmt,
/* log_level_unknown signals the start of a new line */
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.
@@ -558,17 +637,7 @@ asmlinkage int vprintk(const char *fmt,
loglev_char = default_message_loglevel
+ '0';
}
- t = sched_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++)
- emit_log_char(*tp);
- printed_len += tlen - 3;
+ printed_len += time_print(loglev_char);
} else {
if (p[0] != '<' || p[1] < '0' ||
p[1] > '7' || p[2] != '>') {
diff -uprN -X dontdiff linux-2.6.13-rc2.orig/kernel/sysctl.c linux-2.6.13-rc2/kernel/sysctl.c
--- linux-2.6.13-rc2.orig/kernel/sysctl.c 2005-07-08 14:18:54.000000000 +0200
+++ linux-2.6.13-rc2/kernel/sysctl.c 2005-07-10 00:46:53.000000000 +0200
@@ -122,6 +122,10 @@ extern int sysctl_hz_timer;
extern int acct_parm[];
#endif

+#ifdef CONFIG_PRINTK_TIME
+extern int printk_time_parm[];
+#endif
+
int randomize_va_space = 1;

static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
@@ -379,6 +383,16 @@ static ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
+#ifdef CONFIG_PRINTK_TIME
+ {
+ .ctl_name = KERN_PRINTK_TIME,
+ .procname = "printk_time",
+ .data = printk_time_parm,
+ .maxlen = 2*sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+#endif
#ifdef CONFIG_KMOD
{
.ctl_name = KERN_MODPROBE,
-
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