Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1309252

Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2]

From Petr Mladek <pmladek@suse.com>
Newsgroups linux.kernel
Subject Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2]
Date 2016-01-14 14:00 +0100
Message-ID <qQPFo-7a4-7@gated-at.bofh.it> (permalink)
References <qQsSu-89F-13@gated-at.bofh.it> <qQtYf-s0-23@gated-at.bofh.it> <qQuKB-11D-1@gated-at.bofh.it> <qQxyO-300-31@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On Wed 2016-01-13 18:28:50, Thomas Gleixner wrote:
> You can solve the whole business by changing the timestamp in printk_log to
> 
>    u64	    mono;
>    u64	    offset_real;

This is not so easy because the structure is proceed by userspace tool,
e.g. crash, see log_buf_kexec_setup(). We would need to update all
the tools as well.


> and have a function which does:
> 
> u64 ktime_get_log_ts(u64 *offset_real)
> {
> 	*offset_real = tk_core.timekeeper.offs_real;
> 
> 	if (timekeeping_active)
> 		return ktime_get_mono_fast_ns();
> 	else
> 		return local_clock();
> }

A solution would be to apply the offset_real immediately. I wonder if
any tool expects the messages to be sorted by a monotonic clock. In
fact, it might be useful to see that some messages are disordered
against the real time, e.g. because of the leaf second.

Best Regards,
Petr

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH 0/2] printk, Add printk.clock kernel parameter [v2] Prarit Bhargava <prarit@redhat.com> - 2016-01-13 13:40 +0100
  Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2] Thomas Gleixner <tglx@linutronix.de> - 2016-01-13 14:50 +0100
    Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2] Prarit Bhargava <prarit@redhat.com> - 2016-01-13 15:40 +0100
      Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2] Thomas Gleixner <tglx@linutronix.de> - 2016-01-13 18:40 +0100
        Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2] Petr Mladek <pmladek@suse.com> - 2016-01-14 14:00 +0100
          Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2] Prarit Bhargava <prarit@redhat.com> - 2016-01-14 15:40 +0100
          Re: [PATCH 0/2] printk, Add printk.clock kernel parameter [v2] Thomas Gleixner <tglx@linutronix.de> - 2016-01-14 15:50 +0100

csiph-web