Hi, This patch series is based on Linus' original reaction to some of the fastboot patches which introduced an "asynchronous initcall level". Linus did not like the initcall level approach much, and wanted a much more finegrained kind of thing. This patch series introduces asynchronous function calls. The goal is still the same (boot faster), the method is entirely different. Asynchronous function calls allow drivers and subsystems to do operations asynchronously, while providing a mechanism to serialize the asynchronous operations at "externally visible" locations, such as device number registrations. As such, this approach is NOT a "full parallel kernel init". For one, it keeps device numbers stable. For another, it's very much opt-in for any code using this. Rather, it is more comparable to an out-of-order cpu, where computations are done asynchronously, but are retired in program order. This series first introduces the infrastructure in patch 1, and then adds users of this infrastructure (scsi in patch2, libata in patch 3 and acpi in patch 4). To see this working, I uploaded a "before" and "after" kernel bootchart for one of my testboxes at http://www.fenrus.org/linux/before.svg http://www.fenrus.org/linux/after.svg As you can see with inkscape (or gimp or any other svg viewer), there is still room for doing more things in parallel, but the 3 example usage patches are a big win already. One comment about the API: Originally I had functionality in mind where the caller of async_schedule() could get back the cookie value of the scheduled task. However I had no users of this, so I removed the code to do this. If someone finds a place where this is useful we can easily add this back. -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
