With a handful of clients, you can ignore contention. My applications have 20s of threads per client making very frequent calls through the service and this means that 10ms delays evolve into seconds of delay fairly quickly.
I believe that if you can measure the contention with tooling, on your desktop, it is a viable goal to reduce it or eliminate it. It's like system time vs user time optimizations of old. Now we are contending for processor cores instead of the processor, locked in the kernel, unable to dispatch more network traffic where it is always convenient to bury latency. Gregg Sent from my iPhone On Dec 4, 2015, at 9:57 AM, Greg Trasuk <tras...@stratuscom.com> wrote: >> On Dec 4, 2015, at 1:16 AM, Peter <j...@zeus.net.au> wrote: >> >> Since ObjectInputStream is a big hotspot, for testing purposes, I merged >> these changes into my local version of River, my validating >> ObjectInputStream outperforms the standard java ois >> >> Then TaskManager, used by the test became a problem, with tasks in >> contention up to 30% of the time. >> >> Next I replaced TaskManager with an ExecutorService (River 3, only uses >> TaskManager in tests now, it's no longer used by release code), but there >> was still contention although not quite as bad. >> >> Then I notice that tasks in the test call Thread.yield(), which tends to >> thrash, so I replaced it with a short sleep of 100ms. >> >> Now monitor state was a maximum of 5%, much better. >> >> After these changes, the hotspot consuming 27% cpu was JERI's >> ConnectionManager.connect, followed by Class.getDeclaredMethod at 15.5%, >> Socket.accept 14.4% and Class.newInstance at 10.8%. > > > First - performance optimization: Unless you’re testing with real-life > workloads, in real-ife-like network environments, you’re wasting your time. > In the real world, clients discover services pretty rarely, and real-world > architects always make sure that communications time is small compared to > processing time. In the real world, remote call latency is controlled by > network bandwidth and the speed of light. Running in the integration test > environment, you’re seeing processor loads, not network loads. There isn’t > any need for this kind of micro-optimization. All you’re doing is delaying > shipping, no matter how wonderful you keep telling us it is. > > >> My validating ois, originating from apache harmony, was modified to use >> explicit constructors during deserialization. This addressed finalizer >> attacks, final field immutability and input stream validation and the ois >> itself places a limit on downloaded bytes by controlling
