On Wed, 13 Feb 2019 14:19:01 +0800 xiang xiao <xiaoxiang781...@gmail.com> wrote:
> On Wed, Feb 13, 2019 at 3:46 AM Steven Rostedt <rost...@goodmis.org> wrote: > > > > On Wed, 13 Feb 2019 02:11:05 +0800 > > Xiang Xiao <xiaoxiang781...@gmail.com> wrote: > > > > > Because log may already add the timestamp sometime > > > > Can you be a bit more detailed on this. When and where does this > > happen? > > Here is my case: > 1.A small MCU(Cortex M4) in SoC run RTOS > 2.RTOS append timestamp to log for the accurate timing > 3.RTOS send log to Linux kernel when buffer exceed the threshold > 4.Kernel call printk to dump the received buffer > So I want that printk skip the timestamp here. > > > If anything, I would probably prefer that we export whether > > time is being printed, and have the caller not print time if printk is > > doing it already, than to add the complexity into printk itself. > > Actually, the timestamp of our initial implementation like your > suggestion come from printk, > but we found that timestamp from kernel isn't accurate as from RTOS > due the buffer and IPC. > If the timestamps are different, then you don't want to remove the printk one. Otherwise you are going to have a confusion between your added timestamp mixed in with the kernel's inaccurate timestamps. -- Steve
