[linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch

* Andrew Morton <akpm(a)osdl.org> wrote: it has already improved the kernel by already detecting at least 2 bugs that were not found via CONFIG_PREEMPT or other means (the cfq-iosched one and the proc_pid_flush() one) - less then 1 week after i wrote the patch. It also already resulted in a number of independent improvements: e.g. the lock-break changes it includes, and all the work on the debug infrastructure. So i fail to see how it would slow the rate of improvement of the kernel. It's simply the middle step towards CONFIG_PREEMPT - a feature that several major distribution have not enabled so far. It's a more opt-in approach instead of CONFIG_PREEMPT's opt-out approach, that's all. (that having said it's not at all clear that voluntary-preempt would get into Fedora. If it causes stability problems it will be zapped. But at least the problems it triggers we could trigger _even on the current UP kernel_, and that's the difference to preempt - CONFIG_PREEMPT triggers _new_ problems on UP.) also, frankly, at minimum the latency side of CONFIG_PREEMPT has been underdeveloped lately. Nobody seemed to care about real latencies that happen. Just do a 'du /; du /; sync' on a box with enough RAM and listen to audio. Or trigger some swapping. (these particular latencies are fixed in the voluntary-preempt patchset.) Ingo