On Thu, Apr 17, 2008 at 02:26:52PM -0500, Anthony Liguori wrote: > This patch introduces a Linux-aio backend that is disabled by default. To > use this backend effectively, the user should disable caching and select > it with the appropriate -aio option. For instance: > > qemu-system-x86_64 -drive foo.img,cache=off -aio linux > > There's no universal way to asynchronous wait with linux-aio. At some point, > signals were added to signal completion. More recently, and eventfd interface > was added. This patch relies on the later. > > We try hard to detect whether the right support is available in configure to > avoid compile failures.
> + do { > + err = io_submit(aio_ctxt_id, 1, iocbs); > + } while (err == -1 && errno == EINTR); > + > + if (err != 1) { > + fprintf(stderr, "failed to submit aio request: %m\n"); > + exit(1); > + } > + > + outstanding_requests++; > + > + return &aiocb->common; > +} > + > +static void la_wait(void) > +{ > + main_loop_wait(10); > +} Sleeping in the context of vcpu's is extremely bad (eg virtio-block blocks in write() throttling which kills performance). It should wait on IO completions instead (qemu-kvm.c creates a pthread "waitqueue" to resolve that issue). Other than that looks fine to me, will give it a try. ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel