Re: [PATCH v3 4/5] trace-cmd split: Enable support for buffer selection

[Steven Rostedt <rostedt@goodmis.org>]

[ Replying to the correct version of the patch I tested ]

On Tue, 23 Jan 2024 14:42:14 +0100
Pierre Gondois <pierre.gondois@arm.com> wrote:

> The 'trace-cmd split' command conserves all buffers/instances
> of the input .dat file. Add support to select the instances to
> keep and to place as the top instance in an output .dat file.
> 
> Multiple .dat files can be generated with different combinations
> of the instances to keep. The first instance in the command line
> is selected as the top instance in an output .dat file.
> 
> For example, with a trace recorded with:
>   $ trace-cmd record -e sched_wakeup -B switch_instance \
>     -e sched_switch -B timer_instance -e timer

I tried this with a trace.dat file that has a instance called "tast" and it
didn't work. Note, the top instance had no data.

  $ trace-cmd split -i /work/traces/trace-tast.dat -o /tmp/trace-tast2.dat -B tast

  $ trace-cmd report /tmp/trace-tast2.dat
cpus=2
tast:        trace-cmd-3559  [001] 59413.154884: sched_waking:         comm=kworker/u4:2 pid=1324 prio=120 target_cpu=000
tast:        trace-cmd-3564  [000] 59413.154900: sched_switch:         trace-cmd:3564 [120] R ==> kworker/u4:2:1324 [120]
tast:        trace-cmd-3559  [001] 59413.154907: sched_switch:         trace-cmd:3559 [120] S ==> trace-cmd:3565 [120]
tast:     kworker/u4:2-1324  [000] 59413.154911: sched_waking:         comm=sshd pid=18725 prio=120 target_cpu=001
tast:     kworker/u4:2-1324  [000] 59413.154929: sched_switch:         kworker/u4:2:1324 [120] I ==> sshd:18725 [120]
tast:             sshd-18725 [000] 59413.155120: sched_waking:         comm=sslh-fork pid=18724 prio=120 target_cpu=001
tast:             sshd-18725 [000] 59413.155178: sched_waking:         comm=kworker/0:1 pid=815 prio=120 target_cpu=000
tast:             sshd-18725 [000] 59413.155189: sched_switch:         sshd:18725 [120] S ==> sslh-fork:18724 [120]
tast:        sslh-fork-18724 [000] 59413.155303: sched_switch:         sslh-fork:18724 [120] S ==> kworker/0:1:815 [120]

Still has "tast" as an instance and not the top.

-- Steve

> 
> Creating a test.dat file containing the top instance and
> the switch_instance:
>   $ trace-cmd split --top -B switch_instance -o test.dat
> 
> Creating a test.dat file containing the switch_instance as
> the top instance, and the initial top instance as an instance
> named 'old_top':
>   $ trace-cmd split -B switch_instance --top=old_top -o test.dat
> 
> Splitting all instances in different .dat files:
>   $ trace-cmd split --top -o top.dat -B switch_instance \
>     -o switch.dat -B timer_instance -o timer.dat
> 
> To achieve this, new 'struct name_list', 'struct output_file_list'
> structures are created, with associated functions.
> 
> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> ---