Notes below are steps I followed to build the realtime (RT) kernel for CentOS. Additional notes are included for patching and building the Starling-X changes against the CentOS realtime kernel.
You'll need a physical (or virtual) machine running CentOS 7.5. Others probably work but this is what I used.
mockrpmbuildgitpatch- probably others...
ssh root@buildhost
adduser mockbuild
usermod -a -G mock mockbuild
yum install mock rpmbuild git patch -y
sudo su - mockbuild
git clone https://git.centos.org/git/centos-git-common.git
mkdir -p ~/.local/bin
ln -s ~/centos-git-common/get_sources.sh ~/.local/bin/
ln -s ~/centos-git-common/into_srpm.sh ~/.local/bin/
ln -s ~/centos-git-common/centos.git.repolist.py ~/.local/bin/
ln -s ~/centos-git-common/return_disttag.sh ~/.local/bin/
ln -s ~/centos-git-common/rpm-tree-prep.sh ~/.local/bin/
ln -s ~/centos-git-common/show_possible_srpms.sh ~/.local/bin/
git clone https://git.centos.org/git/rpms/kernel-rt
cd kernel-rt/
git fetch --all
git checkout origin/c7-rt
git log # note the commit hash for the version of the kernel you want
git checkout a7516c3fe0241f3d74efbf2bcedf267764c0c789
git checkout -b c7
get_sources.sh
into_srpm.sh
mock --root epel-7-x86_64 \
--rebuild \
--resultdir ./RPMS \
--rootdir ~/builddir \
SRPMS/kernel-rt-3.10.0-862.11.6.rt56.819.el7.src.rpm
git clone https://git.centos.org/git/rpms/kernel-rt kernel-rt-stx
cd kernel-rt-stx/
git fetch --all
git checkout origin/c7-rt
git checkout a7516c3fe0241f3d74efbf2bcedf267764c0c789
git checkout -b c7
get_sources.sh
cd ~
git clone https://github.com/openstack/stx-integ.git
cat stx-integ/kernel/kernel-rt/meta_patches/PATCH_ORDER
cd ~/kernel-rt-stx
patch -p1 < ~/stx-integ/kernel/kernel-rt/centos/meta_patches/Build-logic-and-sources-for-TiC.patch
patch -p1 < ~/stx-integ/kernel/kernel-rt/centos/meta_patches/Kernel-source-patches-for-TiC.patch
patch -p1 < ~/stx-integ/kernel/kernel-rt/centos/meta_patches/Compile-issues.patch
cp ~/stx-integ/kernel/kernel-rt/files/* ./SOURCES/
cp ~/stx-integ/kernel/kernel-rt/centos/patches/* ./SOURCES/
# then I needed to change ~/.local/bin/into_srpm.sh
# to add `--define "tis_patch_ver 43" to the `rpmbuild` command
into_srpm.sh
mock --root epel-7-x86_64 \
--define "tis_patch_ver 43" \
--rootdir=$HOME/builddir \
--rebuild \
--resultdir ./RPMS \
SRPMS/kernel-rt-3.10.0-862.11.6.rt56.819.el7.tis.43.src.rpm
Boot up a CentOS 7.5 virtual machine (or physical host) and copy over the resulting
RPMs from the ~/kernel-rt/RPMS/ and/or ~/kernel-rt-stx/RPMS/ directories to the
testing machine.
Add the CentOS RT repository.
sudo tee /etc/yum.repos.d/CentOS-rt.repo >/dev/null <<EOF
[rt]
name=CentOS-7 - rt
baseurl=http://mirror.centos.org/centos/\$releasever/rt/\$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF
Then we need to downgrade tuned to version 2.8.0 as required by the kernel.
sudo yum downgrade --enablerepo=rt tuned-2.8.0-5.el7.noarch
At this point we can install the RT kernel and reboot. You won't be able to install
everything at this point as you'll get conflicts. You likely only need the kernel
anyways, but if you need the kernel-tools and other packages, you'll need to remove
the conflicting kernel-tools from the non-RT kernel installed, and then add
the RT kernel tools. I did this after rebooting into the RT kernel, but you can likely
do this before rebooting as well.
sudo yum install --enablerepo=rt kernel-rt-3.10.0-862.11.6.rt56.819.el7.tis.43.x86_64.rpm
sudo yum install deltarpm
sudo systemctl reboot
sudo yum remove kernel-tools-libs-3.10.0-862.14.4.el7.x86_64 kernel-tools-3.10.0-862.14.4.el7.x86_64
sudo yum install --enablerepo=rt kernel-rt-stx/*.x86_64.rpm
sudo yum install --enablerepo=rt rt-tests
We can start running our tests now with cyclictest. The -l is a value is number of
loops to run. I found that 10000 seemed to equate to roughly 10 seconds, so apply
the value most appropriate.
sudo bash -c 'time cyclictest -t1 -p 99 -i 1000 -n -l 10000 -d 86400 -m -a 1'