Re: [Buildroot] [PATCH 3/4] package/linux-tools: add rtla

[Maxime Chevallier via buildroot <buildroot@buildroot.org>]

Hello Andreas,

On Sun, 05 Feb 2023 09:22:56 +0100
Andreas Ziegler <br015@umbiko.net> wrote:

> Hi Maxime,
> 
> I was able to build RTLA after some adaptions, see below.

Thanks for the effort, I appreciate !

> On 2023-01-30 18:44, Maxime Chevallier wrote:
> > 
> > The RealTime Linux Analysis tool includes a set of commands that
> > relies on the osnoise and timerlat tracers from the ftrace kernel
> > subsystem, allowing to analyze the lantency sources coming from the
> > hardware and the kernel itself.
> > 
> > This tool was introduced in v5.17, and relies on libtracefs and
> > libtraceevent, although libtraceevent itself is already a
> > dependency for
> > libtracefs.
> > 
> > Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> > ---
> >  DEVELOPERS                                |  1 +
> >  package/linux-tools/Config.in             | 10 +++++++
> >  package/linux-tools/linux-tool-rtla.mk.in | 32
> > +++++++++++++++++++++++ 3 files changed, 43 insertions(+)
> >  create mode 100644 package/linux-tools/linux-tool-rtla.mk.in
> > 
> > diff --git a/DEVELOPERS b/DEVELOPERS
> > index fe7194f817..8f459c796a 100644
> > --- a/DEVELOPERS
> > +++ b/DEVELOPERS
> > @@ -2109,6 +2109,7 @@ F:	package/timescaledb/
> >  N:	Maxime Chevallier <maxime.chevallier@bootlin.com>
> >  F:	package/libtraceevent/
> >  F:	package/libtracefs
> > +F:	package/linux-tools/linux-tool-rtla.mk.in
> > 
> >  N:	Michael Durrant <mdurrant@arcturusnetworks.com>
> >  F:	board/arcturus/
> > diff --git a/package/linux-tools/Config.in 
> > b/package/linux-tools/Config.in
> > index 8a0b6d5802..186392b816 100644
> > --- a/package/linux-tools/Config.in
> > +++ b/package/linux-tools/Config.in
> > @@ -102,6 +102,16 @@ config 
> > BR2_PACKAGE_LINUX_TOOLS_PERF_NEEDS_HOST_PYTHON3
> > 
> >  endif
> > 
> > +config BR2_PACKAGE_LINUX_TOOLS_RTLA
> > +	bool "rtla"  
> 
> Since a version dependency exists, you might add:
> 	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_17

Good call !

> > +	select BR2_PACKAGE_LINUX_TOOLS
> > +	select BR2_PACKAGE_LIBTRACEFS
> > +	help
> > +	  Linux 5.17 and later has 2 new tracers, osnoise and
> > timerlat.
> > +	  There tracers allow performing latency analysis, for
> > which
> > +	  the rtla tool provides wrapper commands to visualize and
> > +	  extrace latency traces and reports.
> > +
> >  config BR2_PACKAGE_LINUX_TOOLS_SELFTESTS
> >  	bool"selftests"
> >  	depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS # bash
> > diff --git a/package/linux-tools/linux-tool-rtla.mk.in 
> > b/package/linux-tools/linux-tool-rtla.mk.in
> > new file mode 100644
> > index 0000000000..a736e3b785
> > --- /dev/null
> > +++ b/package/linux-tools/linux-tool-rtla.mk.in
> > @@ -0,0 +1,32 @@
> > +################################################################################
> > +#
> > +# rtla
> > +#
> > +################################################################################
> > +
> > +LINUX_TOOLS += rtla
> > +
> > +RTLA_DEPENDENCIES = host-pkgconf libtracefs  
> 
> RTLA needs some kernel features; better to include them here, saves
> time experimenting:
> 
> # linux kernel needs FTRACE, TIMERLAT_TRACER, HIST_TRIGGERS for RTLA
> to work
> ifeq ($(BR2_PACKAGE_LINUX_TOOLS_RTLA),y)
> define RTLA_LINUX_CONFIG_FIXUPS
> 	$(call KCONFIG_ENABLE_OPT,CONFIG_FTRACE)
> 	$(call KCONFIG_ENABLE_OPT,CONFIG_TIMERLAT_TRACER)
> 	$(call KCONFIG_ENABLE_OPT,CONFIG_HIST_TRIGGERS)
> endef
> endif

Oh I wasn't aware that we could enable kernel options that way. I'll
include them in the v2, along with CONFIG_OSNOISE_TRACER that is also
required.

> > +RTLA_MAKE_OPTS = $(LINUX_MAKE_FLAGS) \
> > +	CC=$(TARGET_CC) \
> > +	LDFLAGS="$(TARGET_LDFLAGS)" \
> > +	PKG_CONFIG_PATH=$(STAGING_DIR)/usr/lib/pkgconfig
> > +  
> 
> The RTLA Makefile unconditionally compiles with stack smashing 
> protection; linking fails on builds configured without this feature:
> 
> # adapted from linux-tool-tmon.mk.in
> ifeq ($(BR2_TOOLCHAIN_HAS_SSP),)
> define RTLA_DISABLE_STACK_PROTECTOR
> 	$(SED) 's/-fstack-protector.* //' 
> $(LINUX_DIR)/tools/tracing/rtla/Makefile
> endef
> endif

Good catch too, I didn't see that.

> > +define RTLA_BUILD_CMDS
> > +	$(Q)if ! grep install
> > $(LINUX_DIR)/tools/tracing/rtla/Makefile   
> > >/dev/null 2>&1 ; then \  
> > +		echo "Your kernel version is too old and does not
> > implement the rtla tool." ; \
> > +		echo "At least kernel 5.17 must be used." ; \
> > +		exit 1 ; \
> > +	fi
> > +  
> 
> 	$(RTLA_DISABLE_STACK_PROTECTOR)
> 
> > +	$(TARGET_MAKE_ENV) \
> > +	$(MAKE) $(RTLA_MAKE_OPTS) \
> > +	-C $(LINUX_DIR)/tools/tracing rtla
> > +endef
> > +
> > +define RTLA_INSTALL_TARGET_CMDS
> > +	$(TARGET_MAKE_ENV) $(MAKE) -C $(LINUX_DIR)/tools/tracing \
> > +	$(RTLA_MAKE_OPTS) \
> > +	DESTDIR=$(TARGET_DIR) \
> > +	rtla_install
> > +endef  
> 
> rtla_install fails with:
> Makefile:34: *** NOTICE: rst2man required to generate man pages.
> Stop. because it tries to build and install man pages also. Better to
> use a custom install command:
> 
> # The rtla_install target tries to create and install manpages,
> # which terminates with an error and cannot be disabled
> define RTLA_INSTALL_TARGET_CMDS
> 	$(INSTALL) -m 0755 -D $(LINUX_DIR)/tools/tracing/rtla/rtla \
> 		$(TARGET_DIR)/usr/bin/rtla
> endef

Ok makes sense as well :)

Thanks a lot for the review, tests and fixes !

Maxime
 
> Kind regards,
> Andreas
> 
> > --
> > 2.39.1  

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