[lttng-dev] [PATCH userspace-rcu v2] Add --enable-rcu-debug to configure

[Mathieu Desnoyers]

Merged into master with small changes to the urcu-qsbr.h modifications.

Thanks,

Mathieu

----- On Jan 23, 2017, at 2:26 PM, Jonathan Rajotte jonathan.rajotte-julien at efficios.com wrote:

> v2: Added CONFIG_RCU_DEBUG template to urcu/include.h.
>    Consider CONFIG_RCU_DEbug in urcu/debug.h.
>    Consider CONFIG_RCU_DEBUG in src/urcu-qsbr.h.
> 
> ------
> 
> When used CONFIG_RCU_DEBUG is defined in urcu/config.h ,thus the
> debugging self-test are used at all time. This allow for a permanent
> built-in debugging behaviour.
> 
> Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien at efficios.com>
> ---
> README.md                | 17 ++++++++++++-----
> configure.ac             |  8 ++++++++
> include/urcu/config.h.in |  4 ++++
> include/urcu/debug.h     |  2 +-
> src/urcu-qsbr.h          |  4 ++++
> 5 files changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/README.md b/README.md
> index 7ce0edf..4615746 100644
> --- a/README.md
> +++ b/README.md
> @@ -358,12 +358,19 @@ can be forced by specifying `--disable-compiler-tls` as
> configure
> argument.
> 
> 
> -### Usage of `DEBUG_RCU`
> +### Usage of `DEBUG_RCU` & `--enable-rcu-debug`
> 
> -`DEBUG_RCU` is used to add internal debugging self-checks to the
> -RCU library. This define adds a performance penalty when enabled.
> -Can be enabled by uncommenting the corresponding line in
> -`Makefile.build.inc`.
> +By default the library is configured with internal debugging
> +self-checks disabled.
> +
> +For always-on debugging self-checks:
> +	./configure --enable-rcu-debug
> +
> +For fine grained enabling of debugging self-checks, build
> +urserspace-rcu with DEBUG_RCU defined and compile dependent
> +applications with DEBUG_RCU defined when necessary.
> +
> +Warning: Enabling this feature result in a performance penalty.
> 
> 
> ### Usage of `DEBUG_YIELD`
> diff --git a/configure.ac b/configure.ac
> index 8ac0c41..dcbb61f 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -26,6 +26,7 @@ AH_TEMPLATE([CONFIG_RCU_ARM_HAVE_DMB], [Use the dmb
> instruction if available for
> AH_TEMPLATE([CONFIG_RCU_TLS], [TLS provided by the compiler.])
> AH_TEMPLATE([CONFIG_RCU_HAVE_CLOCK_GETTIME], [clock_gettime() is detected.])
> AH_TEMPLATE([CONFIG_RCU_FORCE_SYS_MEMBARRIER], [Require the operating system to
> support the membarrier system call for default and bulletproof flavors.])
> +AH_TEMPLATE([CONFIG_RCU_DEBUG], [Enable internal debugging self-checks.
> Introduce performance penalty.])
> 
> # Allow requiring the operating system to support the membarrier system
> # call. Applies to default and bulletproof flavors.
> @@ -253,6 +254,13 @@ AC_ARG_ENABLE([smp-support],
> 	[def_smp_support="yes"])
> AS_IF([test "x$def_smp_support" = "xyes"], [AC_DEFINE([CONFIG_RCU_SMP], [1])])
> 
> +# RCU debugging option
> +AC_ARG_ENABLE([rcu-debug],
> +      AS_HELP_STRING([--enable-rcu-debug], [Enable internal debugging
> +		      self-checks. Introduce performance penalty.]))
> +AS_IF([test "x$enable_rcu_debug" = "xyes"], [
> +       AC_DEFINE([CONFIG_RCU_DEBUG], [1])
> +])
> 
> # From the sched_setaffinity(2)'s man page:
> # ~~~~
> diff --git a/include/urcu/config.h.in b/include/urcu/config.h.in
> index bb128a1..9ed0454 100644
> --- a/include/urcu/config.h.in
> +++ b/include/urcu/config.h.in
> @@ -26,3 +26,7 @@
> /* Require the operating system to support the membarrier system call for
>    default and bulletproof flavors. */
> #undef CONFIG_RCU_FORCE_SYS_MEMBARRIER
> +
> +/* Enable internal debugging self-checks.
> +   Introduce performance penalty. */
> +#undef CONFIG_RCU_DEBUG
> diff --git a/include/urcu/debug.h b/include/urcu/debug.h
> index 327bd92..14b50b6 100644
> --- a/include/urcu/debug.h
> +++ b/include/urcu/debug.h
> @@ -21,7 +21,7 @@
> 
> #include <assert.h>
> 
> -#ifdef DEBUG_RCU
> +#if defined(DEBUG_RCU) || defined(CONFIG_RCU_DEBUG)
> #define urcu_assert(...)	assert(__VA_ARGS__)
> #else
> #define urcu_assert(...)
> diff --git a/src/urcu-qsbr.h b/src/urcu-qsbr.h
> index bf17361..06c7064 100644
> --- a/src/urcu-qsbr.h
> +++ b/src/urcu-qsbr.h
> @@ -47,6 +47,10 @@ extern "C" {
> #define DEBUG_RCU
> #endif
> 
> +#ifdef CONFIG_RCU_DEBUG
> +#define DEBUG_RCU
> +#endif
> +
> /*
>  * Important !
>  *
> --
> 2.7.4

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com