Re: Merge ftrace data of host and guest

From: Divya Vyas
Date: Mon Dec 22 2014 - 02:04:36 EST


Hi Steven,

I am sorry but I am very new to trace-cmd , that's why I didn't knew
what you are working on it.

I will explain you whole scenario , Actually I have multiple guests
and a host and I want to see all traces on a single file with
trace-cmd report command and may be kernelshark also .

trace-cmd report -i guest.dat -i host.dat command is giving me all
traces is single file but the timestamp is different for guest . So
the challenge for me is to sync the timestamp of guest and host . Can
you advise me something in this ? How can I sync gettimeofday clocks
of guest and host ?

and kernelshark doesnt take trace-cmd report input , I think it takes
guest.dat and host.dat .
Is there any other viewer available for ftrace ?






On Sat, Dec 20, 2014 at 10:40 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Fri, Dec 19, 2014 at 05:52:52PM +0530, Divya Vyas wrote:
>> Hi,
>
> Hi, it would be helpful if you Cc'd me. I would have responded quicker. Luckily,
> someone noticed this email and told me about it.
>
>>
>> I think it is not desired output . Ths script is written for diffrent
>> format .ftrace format is ( trace-cmd report command generates) :
>
> I'm actually working on trace-cmd this week and hopefully I'll be able to release
> 2.5 by x-mas.
>
> I believe that Masami is going to start continuing work on the virt guest
> tracer for trace-cmd.
>
> Also, for now, for a crud way of merging, if both the gettimeofday clocks
> of the host and guest are synced, you could do:
>
> guest> trace-cmd record -o guest.dat --date ...
>
> host> trace-cmd record -o host.dat --date ...
>
> and then run:
>
> trace-cmd report -i guest.dat -i host.dat
>
> and trace-cmd will merge the two. The --date will add a way to sync the trace
> timestamps to a wall clock and that will be used to try to interleave the
> events of both the data files.
>
> -- Steve
>
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