1. The Globus Toolkit V4.0 WSRF-C Performance Aspects Sam Lang, ANL GlobusWORLD 10 Feb 2005

2. GT4: Programming to Events l Some Definitions: u Event - System Call, I/O u Asynchronous - No ordering requirements for events, things happen when ready. Callbacks handle incoming events. u Non-blocking - A function that doesn’t wait for an event to complete before exiting u Blocking - A function must wait for an event u Register - Mapping a handler to an event l GT4 WSRF-C Events u Request/Response Sent u Request/Response Received u Notification (State Change)

3. Event Programming Cont. l Register for an Event u A handler or callback function is written myResourcePropertyCallback(ResourcePropertyValue val) { … } u Callback is passed to a non-blocking register function GetResourcePropertyRegister(endpoint, myResourcePropertyCallback); u GetResourceProperty call gets a response, handler is called l Internals: Flavors and Threads u Programming model internally manages threads u User must manage shared data u Can be built with/without threads

4. Events and Performance l Useful in Asynchronous Environments l Performing Many WS operations u In Sequence: 1. Send Request -> Wait -> Receive Response 2. Send Request -> Wait -> Receive Response 3. … u Asynchronously: 1. Send Request A 2. Send Request B 3. … 4. Receive Response A 5. Receive Response B 6. …

5. Events and WSRF l Polling: WS-ResourceProperties u State is exposed by ResourceProperties u State is distributed in grid environments l Pushing: WS-Notifications u Notifications are events u Implement a callback handler for notifications u Subscribe to Notification Topics (maybe RPs) and register callback for notifications u Many notifications, one callback l Web Service Container u Invocations trigger event handling code, calling service impl

6. Performance Numbers l Many GetResourceProperty operations u In Sequence: u Asynchronously: