Re: [PATCH v7 09/16] tracing: Add hist trigger snapshot() action test case

[Masami Hiramatsu <mhiramat@kernel.org>]

On Wed, 14 Nov 2018 14:18:06 -0600
Tom Zanussi <zanussi@kernel.org> wrote:

> From: Tom Zanussi <tom.zanussi@linux.intel.com>
> 
> Add a test case verifying the basic functionality of the
> hist:snapshot() action.
> 
> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> ---
>  .../inter-event/trigger-snapshot-action-hist.tc    | 43 ++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
>  create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-snapshot-action-hist.tc
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-snapshot-action-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-snapshot-action-hist.tc
> new file mode 100644
> index 000000000000..a0a51e6a6a0c
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-snapshot-action-hist.tc
> @@ -0,0 +1,43 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: event trigger - test inter-event histogram trigger snapshot action
> +
> +fail() { #msg
> +    echo $1
> +    exit_fail
> +}
> +
> +if [ ! -f set_event ]; then
> +    echo "event tracing is not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -f snapshot ]; then
> +    echo "snapshot is not supported"
> +    exit_unsupported
> +fi
> +
> +grep -q "onchange(var)" README > /dev/null || exit_unsupported # version issue
> +
> +grep -q "snapshot()" README > /dev/null || exit_unsupported # version issue

"grep -q ... > /dev/null" is redundant, since -q doesn't show anything.
please drop "> /dev/null" redirection.

> +
> +echo "Test snapshot action"
> +
> +echo 1 > /sys/kernel/debug/tracing/events/sched/enable
> +
> +echo 'hist:keys=comm:newprio=prio:onchange($newprio).save(comm,prio):onchange($newprio).snapshot() if comm=="ping"' >> /sys/kernel/debug/tracing/events/sched/sched_waking/trigger

This tests onchange().snapshot(), but document change only describes onmax().snapshot().
Maybe we should improve document too.

> +
> +ping $LOCALHOST -c 3
> +nice -n 1 ping $LOCALHOST -c 3
> +
> +echo 0 > /sys/kernel/debug/tracing/events/sched/enable

Shouldn't we stop tracing instead of disabling the event?

Thank you,

> +
> +if ! grep -q "changed:" events/sched/sched_waking/hist; then
> +    fail "Failed to create onchange action inter-event histogram"
> +fi
> +
> +if ! grep -q "comm=ping" snapshot; then
> +    fail "Failed to create snapshot action inter-event histogram"
> +fi
> +
> +exit 0
> -- 
> 2.14.1
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>