Commit 649e6ee3 authored by Kay Sievers's avatar Kay Sievers Committed by Greg Kroah-Hartman
Browse files

printk() - restore timestamp printing at console output 



The output of the timestamps got lost with the conversion of the
kmsg buffer to records; restore the old behavior.

Document, that CONFIG_PRINTK_TIME now only controls the output of
the timestamps in the syslog() system call and on the console, and
not the recording of the timestamps.

Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Reported-by: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarKay Sievers <kay@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5c5d5ca5

kernel/printk.c

+26 −17
Original line number Diff line number Diff line
@@ -786,6 +786,22 @@ static bool printk_time; 
#endif

module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);



static size_t prepend_timestamp(unsigned long long t, char *buf)

{

	unsigned long rem_ns;



	if (!printk_time)

		return 0;



	if (!buf)

		return 15;



	rem_ns = do_div(t, 1000000000);



	return sprintf(buf, "[%5lu.%06lu] ",

		       (unsigned long) t, rem_ns / 1000);

}



static int syslog_print_line(u32 idx, char *text, size_t size)

{

	struct log *msg;
@@ -800,9 +816,7 @@ static int syslog_print_line(u32 idx, char *text, size_t size) 
			len++;

		if (msg->level > 99)

			len++;



		if (printk_time)

			len += 15;

		len += prepend_timestamp(0, NULL);



		len += msg->text_len;

		len++;
@@ -810,15 +824,7 @@ static int syslog_print_line(u32 idx, char *text, size_t size) 
	}



	len = sprintf(text, "<%u>", msg->level);



	if (printk_time) {

		unsigned long long t = msg->ts_nsec;

		unsigned long rem_ns = do_div(t, 1000000000);



		len += sprintf(text + len, "[%5lu.%06lu] ",

				   (unsigned long) t, rem_ns / 1000);

	}



	len += prepend_timestamp(msg->ts_nsec, text + len);

	if (len + msg->text_len > size)

		return -EINVAL;

	memcpy(text + len, log_text(msg), msg->text_len);
@@ -1741,7 +1747,7 @@ again: 
	for (;;) {

		struct log *msg;

		static char text[LOG_LINE_MAX];

		size_t len;

		size_t len, l;

		int level;



		raw_spin_lock_irqsave(&logbuf_lock, flags);
@@ -1761,10 +1767,13 @@ again: 


		msg = log_from_idx(console_idx);

		level = msg->level & 7;

		len = msg->text_len;

		if (len+1 >= sizeof(text))

			len = sizeof(text)-1;

		memcpy(text, log_text(msg), len);



		len = prepend_timestamp(msg->ts_nsec, text);

		l = msg->text_len;

		if (len + l + 1 >= sizeof(text))

			l = sizeof(text) - len - 1;

		memcpy(text + len, log_text(msg), l);

		len += l;

		text[len++] = '\n';



		console_idx = log_next(console_idx);

lib/Kconfig.debug

+10 −6
Original line number Diff line number Diff line
@@ -3,12 +3,16 @@ config PRINTK_TIME 
	bool "Show timing information on printks"

	depends on PRINTK

	help

	  Selecting this option causes timing information to be

	  included in printk output.  This allows you to measure

	  the interval between kernel operations, including bootup

	  operations.  This is useful for identifying long delays

	  in kernel startup.  Or add printk.time=1 at boot-time.

	  See Documentation/kernel-parameters.txt

	  Selecting this option causes time stamps of the printk()

	  messages to be added to the output of the syslog() system

	  call and at the console.



	  The timestamp is always recorded internally, and exported

	  to /dev/kmsg. This flag just specifies if the timestamp should

	  be included, not that the timestamp is recorded.



	  The behavior is also controlled by the kernel command line

	  parameter printk.time=1. See Documentation/kernel-parameters.txt



config DEFAULT_MESSAGE_LOGLEVEL

	int "Default message log level (1-7)"

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