Messages in this thread Patch in this message | | | Subject | Re: [PATCH RESEND 1/3] printk: convert byte-buffer to variable-length record buffer | From | Kay Sievers <> | Date | Thu, 10 May 2012 04:30:45 +0200 |
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On Wed, 2012-05-09 at 16:06 -0700, Greg Kroah-Hartmann wrote: > On Wed, May 09, 2012 at 04:02:40PM -0700, Yinghai Lu wrote: > > On Wed, May 9, 2012 at 7:37 AM, Kay Sievers <kay@vrfy.org> wrote: > > > > > >> Changing printk semantics and trying to stabilize > > >> printk message content are bad ideas though. > > > > > > Again, nobody talks about content of here. > > > > printk_time=1 does not work anymore with this patch on serial console. > > Known issue, I think Kay is working on the solution for this right > now...
Sure, and this seems to work for me.
Thanks, Kay
From: Kay Sievers <kay@vrfy.org> Subject: 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.
Signed-off-by: Kay Sievers <kay@vrfy.org> ---
kernel/printk.c | 43 ++++++++++++++++++++++++++----------------- lib/Kconfig.debug | 16 ++++++++++------ 2 files changed, 36 insertions(+), 23 deletions(-)
--- a/kernel/printk.c +++ b/kernel/printk.c @@ -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, ch 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, ch } 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); --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -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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