tracing: Add TRACE_CUSTOM_EVENT() macro

To make it really easy to add custom events from modules, add a
TRACE_CUSTOM_EVENT() macro that acts just like the TRACE_EVENT() macro,
but creates a custom e

tracing: Add TRACE_CUSTOM_EVENT() macro

To make it really easy to add custom events from modules, add a
TRACE_CUSTOM_EVENT() macro that acts just like the TRACE_EVENT() macro,
but creates a custom event to an already existing tracepoint.

The trace_custom_sched.[ch] has been updated to use this new macro to show
how simple it is.

Link: https://lkml.kernel.org/r/[email protected]

Cc: Ingo Molnar <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Tom Zanussi <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

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tracing: Add sample code for custom trace events

Add sample code to show how to create custom trace events in the tracefs
directory that can be enabled and modified like any event in tracefs
(includ

tracing: Add sample code for custom trace events

Add sample code to show how to create custom trace events in the tracefs
directory that can be enabled and modified like any event in tracefs
(including triggers, histograms, synthetic events and event probes).

The example is creating a custom sched_switch and a sched_waking to limit
what is recorded:

If the custom sched switch only records the prev_prio, next_prio and
next_pid, it can bring the size from 64 bytes per event, down to just 16
bytes!

If sched_waking only records the prio and pid of the woken event, it will
bring the size down from 36 bytes to 12 bytes per event.

This will allow for a much smaller footprint into the ring buffer and keep
more events from dropping.

Link: https://lkml.kernel.org/r/[email protected]

Cc: Ingo Molnar <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Tom Zanussi <[email protected]>
Suggested-by: Joel Fernandes <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

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treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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tracing: update sample event documentation

The comments in the sample code is a bit confusing. This patch
cleans them up a little.

Signed-off-by: Steven Rostedt <[email protected]>

tracing: small trave_events sample Makefile cleanup

Use -I$(src) to add the current directory the include path.

[ Impact: cleanup ]

Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Steven R

tracing: small trave_events sample Makefile cleanup

Use -I$(src) to add the current directory the include path.

[ Impact: cleanup ]

Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <[email protected]>

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tracing/events: add trace-events-sample

This patch adds a sample to the samples directory on how to create
and use TRACE_EVENT trace points.

Signed-off-by: Steven Rostedt <[email protected]>