Re: [PATCH v2 01/32] tracing: Allow gcov profiling on only ftrace subsystem

On Fri, 17 Aug 2018 01:29:39 +0900 Masami Hiramatsu mhiramat@kernel.org wrote:

Add GCOV_PROFILE_FTRACE to allow gcov profiling on only files in ftrace subsystem. This kconfig flag will be used for checking kselftest/ftrace

Note, I haven't heard of "kconfig flag" as the terminology. Usually, we just say "config" or "config option".

coverage.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org

kernel/trace/Kconfig | 13 +++++++++++++ kernel/trace/Makefile | 5 +++++ 2 files changed, 18 insertions(+)

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index fd6754b88f87..8decf6d8553a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -774,6 +774,19 @@ config TRACING_EVENTS_GPIO help Enable tracing events for gpio subsystem +config GCOV_PROFILE_FTRACE

• bool "Enable GCOV profiling on ftrace subsystem"
• depends on GCOV_KERNEL
• help

•  Enable GCOV profiling on ftrace subsystem for checking
  

•  which functions/lines are tested.
  

•  If unsure, say N.
  

•  Note that on a kernel compiled with this flags, ftrace will be
  

•  significantly run slower. So do not enable it for production
  

•  kernel.
  

I would rewrite the above as:

Note that on a kernel compiled with this config, ftrace will run significantly slower.

I think we can leave out the production sentence. It should be obvious from the "significantly slower" part.

Other than that, it looks fine to me.

-- Steve

endif # FTRACE endif # TRACING_SUPPORT diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 98d53b39a8ee..f81dadbc7c4a 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -23,6 +23,11 @@ ifdef CONFIG_TRACING_BRANCHES KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING endif +# for GCOV coverage profiling +ifdef CONFIG_GCOV_PROFILE_FTRACE +GCOV_PROFILE := y +endif

CFLAGS_trace_benchmark.o := -I$(src) CFLAGS_trace_events_filter.o := -I$(src)