On Tue, 2011-04-19 at 19:52 +0300, Pekka Enberg wrote: > On Mon, Apr 18, 2011 at 4:02 PM, Sasha Levin <levinsasha928@xxxxxxxxx> wrote: > > Add --debug-io-delay-cycles and --debug-io-delay-amount to delay the completion of IO requests within virtio-blk. > > This feature allows to verify and debug the threading within virtio-blk. > > > > Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx> > > Well, to be honest, I'm not convinced we need both of these. Isn't > --debug-io-delay=<msec> enough for our use? This came up during our testing. Ingo suggested a large delay so we could easily see the results of threading. The problem we encountered was that having a delay right from the beginning will make the guest kernel take a rather long time to boot and would make actually testing the threading impossible. I've added a delay before the activation of the I/O request completion delay to give the tester/debugger enough time to boot into the guest and prepare anything needed for the test. Making it a constant is also rather hard because different kernels can take a very different amount of I/O requests to boot. Take the simple example of a whether fsck was running during the boot or not. -- Sasha. -- 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
