Messages in this thread | | | Date | Tue, 28 Jun 2016 09:57:27 -0400 | From | Steven Rostedt <> | Subject | Re: [QUESTION] Is there a better way to get ftrace dump on guest? |
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On Tue, 28 Jun 2016 15:33:18 +0900 Namhyung Kim <namhyung@kernel.org> wrote:
> 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..
Heh, I'd say something helpful but you basically already shot down all of my advice, because what I do is...
1) Reduce the size of the ring buffer
2) Dump out just one CPU
3) use kexec/kdump and make a crash kernel to extract trace.dat from
That's my debugging environment, but it looks like you want something else.
-- Steve
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