Re: [PATCH] perf script: format regression due to libtraceevent

[Steven Rostedt <rostedt@goodmis.org>]

On Thu, 2012-06-14 at 09:48 -0600, David Ahern wrote:
> Consider the commands:
> perf record -e sched:sched_switch -fo /tmp/perf-3.5.data  -a -- sleep 1
> perf script -i /tmp/perf.data
> 
> In v3.4 the output has the form (lines wrapped)
>             perf 29214 [005] 821043.582596: sched_switch:
> prev_comm=perf prev_pid=29214 prev_prio=120
> prev_state=S ==> next_comm=swapper/5 next_pid=0 next_prio=120
> 
> In 3.5 that same line has become:
>            perf 29214 [005] 821043.582596: sched_switch:
>             <...>-29214 [005]     0.000000000: sched_switch:
>          prev_comm=perf prev_pid=29214 prev_prio=120
> prev_state=S ==> next_comm=swapper/5 next_pid=0 next_prio=120
> 
> Note the duplicates in the output -- pid, cpu, event name. With
> this patch the v3.4 output is restored:
>            perf 29214 [005] 821043.582596: sched_switch:
> prev_comm=perf prev_pid=29214 prev_prio=120
> prev_state=S ==> next_comm=swapper/5 next_pid=0 next_prio=120
> 

This patch breaks trace-cmd (as well as the API). I recommend adding
another function that just does what you want and call that instead.

-- Steve