Re: [QUESTION] Is there a better way to get ftrace dump on guest?

Namhyung Kim
2016-06-28T06:33:39Z

Send again to correct addresses, sorry!

On Tue, Jun 28, 2016 at 3:25 PM, Namhyung Kim <namhyung@kernel.org> wrote:
> Hello,
>
> I'm running some guest machines for kernel development. For debugging
> purpose, I use lots of trace_printk() since it's faster than normal
> printk(). When kernel crash happens the trace buffer is printed on
> console (I set ftrace_dump_on_oops) but it takes too much time. I
> don't want to reduce the size of ring buffer as I want to collect the
> debug info as much as possible. And I also want to see trace from all
> cpu so 'ftrace_dump_on_oop = 2' is not an option.
>
> I know the kexec/kdump (and the crash tool) can dump and analyze the
> trace buffer later. But it's cumbersome to do it everytime and more
> importantly, I don't want to spend the memory for the crashkernel.
>
> So what is the best way to handle this? I'd like to know how others
> setup the debugging environment..