[lttng-dev] [PATCH lttng-tools 11/14] Added configure.ac check for pthread_cond_timedwait_monotonic support (which is a non-standard pthread function) & usage handling in sessiond's main.c.

[David Goulet]

A compat layer should be used here for pthread.

Charles Briere:
> From: Michael Poupart <michael-poupart at polymtl.ca>
> 
> Signed-off-by: Michael Poupart <michael-poupart at polymtl.ca>
> ---
>  configure.ac                  | 17 +++++++++++++++++
>  src/bin/lttng-sessiond/main.c |  7 +++++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/configure.ac b/configure.ac
> index b3738d2..c405020 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -182,6 +182,23 @@ AM_CONDITIONAL([LTTNG_BUILD_WITH_LIBUUID], [test "x$have_libuuid" = "xyes"])
>  AM_CONDITIONAL([LTTNG_BUILD_WITH_LIBC_UUID], [test "x$have_libc_uuid" = "xyes"])
>  AM_CONDITIONAL([LTTNG_BUILD_WITH_LIBEXT2_UUID], [test "x$have_libext2_uuid" = "xyes"])
>  
> +# Check for the non-standard pthread_cond_timedwait_monotonic function in lpthread/libc
> +AC_CHECK_LIB([pthread], [pthread_cond_timedwait_monotonic],
> +[
> +	have_pthread_cndtmwt_mono=yes
> +],
> +[
> +	AC_CHECK_LIB([c], [pthread_cond_timedwait_monotonic],
> +	[
> +		have_pthread_cndtmwt_mono=yes
> +	])
> +])
> +AS_IF([test "x$have_pthread_cndtmwt_mono" = "xyes"],
> +[
> +	AC_DEFINE_UNQUOTED([LTTNG_HAVE_PTHREAD_CNDTMWT_MONO], 1, [Has non-standard pthread_cond_timedwait_monotonic support.])
> +])
> +
> +
>  # URCU library version needed or newer
>  liburcu_version=">= 0.7.2"
>  
> diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
> index f6a051a..d8ff4c2 100644
> --- a/src/bin/lttng-sessiond/main.c
> +++ b/src/bin/lttng-sessiond/main.c
> @@ -1732,6 +1732,7 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
>  		goto error;
>  	}
>  
> +#ifndef LTTNG_HAVE_PTHREAD_CNDTMWT_MONO
>  	/*
>  	 * Set the monotonic clock in order to make sure we DO NOT jump in time
>  	 * between the clock_gettime() call and the timedwait call. See bug #324
> @@ -1743,6 +1744,7 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
>  		PERROR("pthread_condattr_setclock consumer data");
>  		goto error;
>  	}
> +#endif
>  
>  	ret = pthread_cond_init(&consumer_data->cond, &consumer_data->condattr);
>  	if (ret != 0) {
> @@ -1792,8 +1794,13 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
>  			ret = pthread_cond_wait(&consumer_data->cond,
>  					&consumer_data->cond_mutex);
>  		} else {
> +#ifdef LTTNG_HAVE_PTHREAD_CNDTMWT_MONO
> +			ret = pthread_cond_timedwait_monotonic(&consumer_data->cond,
> +					&consumer_data->cond_mutex, &timeout);
> +#else
>  			ret = pthread_cond_timedwait(&consumer_data->cond,
>  					&consumer_data->cond_mutex, &timeout);
> +#endif
>  		}
>  	}
>