Running on rv64 arch

[Limraj]

Script to run natively on Gentoo rv64

source /etc/profile

#prep suffix
emerge dev-java/openjdk:21 tomcat:9 pwgen
useradd -m -G users,wheel,realtime -s /bin/bash scadalts
/usr/share/tomcat-9/gentoo/tomcat-instance-manager.bash --create --suffix scadalts --user scadalts --group scadalts
echo 'TOMCAT_JVM="openjdk-21"' >> /etc/conf.d/tomcat-9-scadalts
echo 'JAVA_OPTS="-Djava.library.path=/usr/lib --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED \
        --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED \
        -Xms512m -Xmx512m -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 -Dignore.endorsed.dirs="' >> /etc/conf.d/tomcat-9-scadalts
echo 'CATALINA_OPTS="-Xmx2G -Xms2G"'  >> /etc/conf.d/tomcat-9-scadalts

#jars
cd /var/lib/tomcat-9-scadalts/webapps
#Download latest Scada-LTS 2.8.0 snapshot, 2.7.8 does not work due to wrong CATALINA_HOME
mkdir /var/lib/tomcat-9-scadalts/lib
cd /var/lib/tomcat-9-scadalts/lib
wget https://github.com/SCADA-LTS/Scada-LTS/raw/refs/heads/develop/tomcat/lib/activation.jar
wget https://github.com/SCADA-LTS/Scada-LTS/raw/refs/heads/develop/tomcat/lib/jaxb-api-2.4.0-b180830.0359.jar
wget https://github.com/SCADA-LTS/Scada-LTS/raw/refs/heads/develop/tomcat/lib/jaxb-core-3.0.2.jar
wget https://github.com/SCADA-LTS/Scada-LTS/raw/refs/heads/develop/tomcat/lib/jaxb-runtime-2.4.0-b180830.0438.jar
wget https://github.com/SCADA-LTS/Scada-LTS/raw/refs/heads/develop/tomcat/lib/mysql-connector-java-5.1.49.jar

#move logs to standard folder
ln -s /var/log/tomcat-9-scadalts /var/lib/tomcat-9-scadalts/logs
mkdir /usr/share/tomcat-9/static
mkdir /usr/share/tomcat-9/static/graphics
chown -R scadalts:scadalts /usr/share/tomcat-9/static/graphics

#optional, map to privileged 80 port and root redirect
sed -i -e 's/8080/80/g' /etc/tomcat-9-scadalts/server.xml
setcap 'cap_net_bind_service=+ep' /usr/lib64/openjdk-21/bin/java
rm /var/lib/tomcat-9-scadalts/webapps/ROOT/index.jsp
echo '<% response.sendRedirect("/Scada-LTS"); %>' > /var/lib/tomcat-9-scadalts/webapps/ROOT/index.jsp
chown scadalts:scadalts /var/lib/tomcat-9-scadalts/webapps/ROOT/index.jsp

#optional, if crappy storage, tmp folder in ramdisk
mkdir /var/tmp/tomcat-9-scadalts
chown scadalts:scadalts /var/tmp/tomcat-9-scadalts
echo 'tmpfs /var/tmp/tomcat-9-scadalts tmpfs rw,uid=1001,gid=1002,size=32M,nr_inodes=10k,mode=0700 0 0' >> /etc/fstab
mount -a

#edit for db credentials /var/lib/tomcat-9-scadalts/conf/context.xml and you're done
#if empty local MariaDB does not want to populate, dump it from another working x86 install and import
rc-service tomcat-9-scadalts start

Different arch SBCs performance testing

Using one db, dumped and imported to test SBCs, with around 400 Modbus TCP points @ 250-1000ms, some IEC101 signals and http retrievers.
Debian systems are vanilla without any tweaks, only set governor to performance, although it seems on x86 intel_pstate ignores it. Gentoo is heavily tweaked.

Celeron J4125, MELE PCG02 eMMC
Linux rtr 6.1.0-31-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.128-1 (2025-02-07) x86_64 GNU/Linux
Scada-LTS docker; MariaDB native
JVM 11.0.22+7 Eclipse Adoptium
org.apache.catalina.startup.Catalina.start Server startup in [26004] milliseconds
24h load average: 0.47
ResetCacheHighestAlarmLevel [6] ms
Avg. consumption 2.2W

Cortex-A72, RPi CM4 8GB RAM / 32GB eMMC no WiFi
Linux raspberrypi 6.6.77-v8+ #1851 SMP PREEMPT Thu Feb 13 13:01:11 GMT 2025 aarch64 GNU/Linux
Scada-LTS docker; MariaDB native
JVM 11.0.22+7 Eclipse Adoptium
org.apache.catalina.startup.Catalina.start Server startup in [60512] milliseconds
24h load average: 0.24
ResetCacheHighestAlarmLevel [3] ms
Avg. consumption 3.5W

JH7110, Milk-V Mars CM 2GB RAM / 8GB eMMC no WiFi
Linux ems.nsa 6.12.13-gentoo-riscv64 #26 SMP PREEMPT_DYNAMIC Tue Feb 11 22:57:50 EET 2025 riscv64 GNU/Linux
Scada-LTS native; MariaDB native
JVM 21.0.6+7 native
org.apache.catalina.startup.Catalina.start Server startup in [76260] milliseconds
24h load average: 0.21
ResetCacheHighestAlarmLevel [1] ms
Avg. consumption 2.7W

rv64 cores, even without vector extensions, are not that slow as many benchmarks are showing them.

How to optimize for a healthy balance of performance and latency on SBCs

• Isolate kernel threads, interrupts (kthread_cpus=0, irqaffinity=0) to first core. Using cgroups isolate all system services to first core, leave 3 cores for MariaDB and Scada-LTS.
• Enable preemption (preempt=full).
• Upgrade to NVMe. If not possible, move tmp to ramdisk, decrease db writes by not logging or infrequent logs of unneeded points.
• Run natively to avoid container overhead. This strongly impacts latency.
• Compile OpenJDK natively with -mcpu= and -mtune= for specific CPU. On a source based distro even better - entire system, with LTO, PGO etc.
• Build a minimalistic monlithic kernel.
• Strip down more overhead such as Systemd. For example benchmarked OpenRC system has only init, agetty, fcron, sshd, chronyd, rsyslogd.

Need futher testing:

• Go full Real-Time with CONFIG_PREEMPT_RT
• Try isolcpus, rcu_nocb_poll, nohz_full

Additional context
2.7.8 currently has CATALINA_HOME path problems on native Gentoo. Run 2.8.0.
catalina.2025-01-09.log
flyway.log
localhost.2025-01-09.log
mango.log