Re: [Qemu-devel] [PATCH] kvm: fix traces to use %x instead of %d

[Stefan Hajnoczi <stefanha@gmail.com>]

On Tue, Sep 03, 2013 at 04:43:46PM +1000, Alexey Kardashevskiy wrote:
> KVM request types are normally defined using hex constants but QEMU traces
> print decimal values instead what is not very convinient.
> 
> This changes the request type format from %d to %x.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>  trace-events | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/trace-events b/trace-events
> index 4574f29..24cf4d2 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1171,9 +1171,9 @@ virtio_ccw_new_device(int cssid, int ssid, int schid, int devno, const char *dev
>  migrate_set_state(int new_state) "new state %d"
>  
>  # kvm-all.c
> -kvm_ioctl(int type, void *arg) "type %d, arg %p"
> -kvm_vm_ioctl(int type, void *arg) "type %d, arg %p"
> -kvm_vcpu_ioctl(int cpu_index, int type, void *arg) "cpu_index %d, type %d, arg %p"
> +kvm_ioctl(int type, void *arg) "type %x, arg %p"
> +kvm_vm_ioctl(int type, void *arg) "type %x, arg %p"
> +kvm_vcpu_ioctl(int cpu_index, int type, void *arg) "cpu_index %d, type %x, arg %p"
>  kvm_run_exit(int cpu_index, uint32_t reason) "cpu_index %d, reason %d"

It would be confusing for someone using these trace events today if you
silently change the base to hex.

To avoid confusion I would use 0x%x or %#x.  This way the output is
self-describing.

Stefan