diff options
| author | Tom Zanussi <zanussi@kernel.org> | 2020-04-03 14:31:21 -0500 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-06-01 08:22:30 -0400 |
| commit | 2d19bd79ae6509858582a9cade739c2e9a4fdca8 (patch) | |
| tree | 7612f1c6d4821e70b8b69d91a0608ae68c4d3413 /kernel/trace/Kconfig | |
| parent | 16b585fe71924b3aebaef5548a291021efaf7c7f (diff) | |
tracing: Add hist_debug trace event files for histogram debugging
Add a new "hist_debug" file for each trace event, which when read will
dump out a bunch of internal details about the hist triggers defined
on that event.
This is normally off but can be enabled by saying 'y' to the new
CONFIG_HIST_TRIGGERS_DEBUG config option.
This is in support of the new Documentation file describing histogram
internals, Documentation/trace/histogram-design.rst, which was
requested by developers trying to understand the internals when
extending or making use of the hist triggers for higher-level tools.
The histogram-design.rst documentation refers to the hist_debug files
and demonstrates their use with output in the test examples.
Link: http://lkml.kernel.org/r/77914c22b0ba493d9783c53bbfbc6087d6a7e1b1.1585941485.git.zanussi@kernel.org
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 743647005f64..2aec9376825f 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -847,6 +847,29 @@ config KPROBE_EVENT_GEN_TEST If unsure, say N. +config HIST_TRIGGERS_DEBUG + bool "Hist trigger debug support" + depends on HIST_TRIGGERS + help + Add "hist_debug" file for each event, which when read will + dump out a bunch of internal details about the hist triggers + defined on that event. + + The hist_debug file serves a couple of purposes: + + - Helps developers verify that nothing is broken. + + - Provides educational information to support the details + of the hist trigger internals as described by + Documentation/trace/histogram-design.rst. + + The hist_debug output only covers the data structures + related to the histogram definitions themselves and doesn't + display the internals of map buckets or variable values of + running histograms. + + If unsure, say N. + endif # FTRACE endif # TRACING_SUPPORT |