On Tue, Jul 24, 2012 at 3:36 AM, Yoshihiro YUNOMAE <yoshihiro.yunomae...@hitachi.com> wrote: > The performance of each method is compared as follows: > [1] Native > - only recording trace data to ring-buffer on a guest > [2] Virtio-trace > - running a trace agent on a guest > - a reader on a host opens FIFO using cat command > [3] IVRing > - A SystemTap script in a guest records trace data to IVRing. > -- probe points are same as ftrace. > [4] Virtio-serial(normal) > - A reader(using cat) on a guest output trace data to a host using > standard output via virtio-serial.
The first time I read this I thought you are adding a new virtio-trace device. But it looks like this series really add splice support to virtio-console and that yields a big performance improvement when sending trace_pipe_raw. Guest ftrace is useful and I like this. Have you thought about controlling ftrace from the host? Perhaps a command could be added to the QEMU guest agent which basically invokes trace-cmd/perf. Are you using text formatted ftrace? Stefan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
