August 20, 2002 Applying RT-Policies in CORBA Component Model Nanbor Wang Department of Computer Science Washington University in St. Louis

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Overview Component composition RTCCM overview –Why, where, and how Iterate thru proposed RT Policies in CIAO –What is the right granularity to apply the policy? –When (or where) to specify –Use case scenarios where the RTCCM approach will/will not work –Does RTCCM approach impose any restrictions on component developers/system integrators?

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Component Packaging IDL/CIDL Compiler User Code Generated Code IDL Component Descriptor Default Properties Compiler Shared Library or Executable Packaging Tool Component Package.zip

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Component Assembly Properties DeploymentT ool Assembly Archive.aar (ZIP) Assembly Tool Component Package Component Package Component Package Port Connections Instance Creation...

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Composition Example Application server –run-time management –service initialization CCM Assembly Archive –Assembly descriptor Install components –Component implementations –Component descriptors –Configuration property files Establish connections

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Component Compositions An assembly descriptor specifies what component implementations are needed by referring to their component descriptors A Component descriptor (.csd) records component features and dependencies to other software modules

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Component Instantiations An assembly descriptor specifies how homes and components should be instantiated A component property file (.cpf) can be associated with a home or a component instantiation to override default component properties

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Connecting Components... modulator modulator EmStop EmStop... Assembly descriptors also specify how component instances are connected tegether

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis RTCCM ≠ CCM + RTCORBA Plain CCM has no mechanisms to specify and enforce RT policies RT policies need to be assured end-to- end for components & connections Trying to ensure RT policies are met in components leads to: –Tight couplings among component implementations –Difficulty in reusing existing components (without RT knowledge) –Failure to utilize many RT mechanisms that go beyond component implementations Component connections –private connections –pre-connections Component collaborations –Thread pools –Thread borrowing Why doesn't running a RTORB beneath CCM make it an RTCCM implementation?

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Real-time CCM (RTCCM) Abstracting RT CORBA related systemic (QoS) aspects –Specify RT policies of a component instance –Specify RT policies of a connection between components –Allocating & computation and communication resources for components –Specify sharing & collaboration of resources among components –Configuring ORB with custom communication mechanisms and options container component RT-ORB container component OS custom transport Application Server ORB Plugins Solution: Configure RT-policies/mechanisms using CCM’s metadata

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis RTCCM Component Packaging IDL/CIDL Compiler User Code Generated Code IDL Component Descriptor Default Properties Compiler Shared Library or Executable Packaging Tool Component Package.zip

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis RTCCM Component Assembly Properties DeploymentT ool Assembly Archive.aar (ZIP) Assembly Tool Component Package Component Package Component Package Port Connections Instance Creation... Resource Allocations ORB Extensions Priority Mappings

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Component-Integrated ACE ORB (CIAO) 1.Component default priority model 2.Override component priority model 3.Priority level of a component instance 4.Defining thread pools 5.Associate thread pools with component instances 6.Specify queuing policies 7.Specify pre-connections 8.Specify private connections 9.Configure ORB components Custom protocols Priority mappings CIAO’s will make RT policies an integral part of deployment metadata

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis RTCCM Descriptor Examples Component default priority model Override component priority model Specify the priority level of a component instance Associate component instances with customized protocols

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis ORB-level (component server instance) Descriptors Define thread pools Plug in custom protocol support Define protocol configuration Plug in custom priority mapping Define priority-banded connection policies Define QoS aggregates...

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis RTCCM Descriptor Examples (cont.) Associate thread pools with components Associate QoS aggregates with connections

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Connection Policies Establishing pre- connections Establishing private connections... modulator modulator EmStop EmStop...

Nanbor Wang Applying RT-Policies in CCM Washington University, St. Louis Other policies? Other RT policies?