Add the official EfficiOS RHEL7 package repository to your system.
wget -P /etc/yum.repos.d/ https://packages.efficios.com/repo.files/EfficiOS-RHEL7-x86-64.repo
Also add the SRPMS repository if you need the sources.
wget -P /etc/yum.repos.d/ https://packages.efficios.com/repo.files/EfficiOS-RHEL7-SRPMS.repo
Import our package signing key.
rpmkeys --import https://packages.efficios.com/rhel/repo.key
And install the packages.
yum install lttng-modules-dkms lttng-tools babeltrace