I have started to migrate from 32bit to 64bit and noticed that the memory has grown from 512Mb armhf to 1G on arm64, and before I start playing with jcmd I just wanted to ask if there were any folks with optimized settings for a midsize installation (387 items, 38 things, and 15 or so bindings). I realize that the jvm size is supposed to double when moving from 32bit to 64bit - just wanted to reduce it slightly with Xmx, Xss, etc…
You can in the Karaf console bundle:stop some components, which you do not use - Language Server, Swagger, IDE … I personally stop the list below. If you use MQTT without HomeAssistant, and openhab without JavaScript and Python (GraalVM), then stopping the HomeAssistant binding will stop loading GraalVM, which will save a lot of RAM. On the other side, if you do not need GraalVM (for MQTT/HomeAssisant, JavaScript, Python (JPython and JRuby do not use GraalVM)), then OpenHAB probably works also in 32 bit mode.
The other thing to look for is Compressed Pointers, see -XX:-UseCompressedOops at The java Command .
openhab> bundle:list |grep -v Active
START LEVEL 100 , List Threshold: 50
ID x State x Lvl x Version x Name
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42 x Resolved x 80 x 2.1.9 x swagger-annotations
43 x Resolved x 80 x 2.1.9 x swagger-core
44 x Resolved x 80 x 2.1.9 x swagger-integration
45 x Resolved x 80 x 2.1.9 x swagger-jaxrs2
46 x Resolved x 80 x 2.1.9 x swagger-models
52 x Resolved x 80 x 3.5.8 x JmDNS
98 x Resolved x 80 x 0.7.7 x jose4j
131 x Resolved x 80 x 0.12.0.v20210402-1305 x org.eclipse.lsp4j
132 x Resolved x 80 x 0.12.0.v20210402-1305 x org.eclipse.lsp4j.jsonrpc
137 x Resolved x 80 x 2.26.0.v20220228-0751 x Xtext IDE Core
140 x Resolved x 80 x 2.26.0.v20220228-0758 x Xbase Generic IDE Services
154 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: OAuth2Client
163 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Configuration mDNS Discovery
179 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: REST mDNS Announcer
182 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: REST Interface :: Swagger 1
185 │ Resolved │ 80 │ 3.4.3 │ openHAB Core :: Bundles :: Voice REST Interface
191 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Model Item IDE
193 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Language Server
195 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Model Persistence IDE
198 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Model Rule IDE
201 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Model Script IDE
204 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Model Sitemap IDE
207 x Resolved x 80 x 3.4.3 x openHAB Core :: Bundles :: Model Thing IDE
257 x Resolved x 81 x 3.4.3 x openHAB Add-ons :: Bundles :: MQTT EspMilightHub
259 x Resolved x 82 x 3.4.3 x openHAB Add-ons :: Bundles :: MQTT HomeAssistant Convention
260 x Resolved x 82 x 3.4.3 x openHAB Add-ons :: Bundles :: MQTT Homie Convention
Stopping (disabling) the bundles must be made after each version upgrade and the numbers (first column) may change between versions.