Messages in this thread | | | Date | Thu, 28 Jan 2016 14:38:16 +0000 (UTC) | From | Mathieu Desnoyers <> | Subject | Re: [RFC][BUG] tracer: Fails to work |
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----- On Jan 28, 2016, at 8:57 AM, Peter Zijlstra peterz@infradead.org wrote:
> On Thu, Jan 28, 2016 at 01:38:00PM +0000, Mathieu Desnoyers wrote: > >> Thoughts ? > > So ideally dumping the trace data would not depend on any of that, > because I can break it all :-) > > Not being able to access the trace data completely and utterly defeats > the purpose of having a tracer in the first place.
One item I have on my todo list is to allow mapping the tracer buffers (lttng in my case) onto RAM that persists across reboots/kexec using dax and the pmem driver. Since the original system is clearly inactive after a reboot, we can read the buffers from memory without caring about synchronization.
That would be one possible way of handling your snapshot-of-buggy-kernel-trace-buffers use-case.
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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