On Thu, Mar 18, 2010 at 05:13:10PM +0100, Ingo Molnar wrote: > > Why does Linux AIO still suck? Why do we not have a proper interface in > > userspace for doing asynchronous file system operations? > > Good that you mention it, i think it's an excellent example. > > The suckage of kernel async IO is for similar reasons: there's an ugly package > separation problem between the kernel and between glibc - and between the apps > that would make use of it. No, kernel async IO sucks because it still does not play well with buffered I/O. Last time I checked (about a year ago or so), AIO syscall latencies were much worse when buffered I/O was used compared to direct I/O. Unfortunately, to achieve good performance with direct I/O, you need a HW RAID card with lots of on-board cache. Gabor -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
