Re: [Qemu-devel] [PATCH v2 1/5] qxl: switch qxl.c to trace-events

[Alon Levy <alevy@redhat.com>]

On Tue, Mar 13, 2012 at 07:42:17AM +0100, Gerd Hoffmann wrote:
> On 03/12/12 16:50, Alon Levy wrote:
> > On Mon, Mar 12, 2012 at 01:43:11PM +0200, Alon Levy wrote:
> >> On Mon, Mar 12, 2012 at 11:20:55AM +0100, Gerd Hoffmann wrote:
> >>> On 03/11/12 20:26, Alon Levy wrote:
> >>>> dprint is still used for qxl_init_common one time prints.
> >>>
> >>> I think we shouldn't simply convert the dprintf's into trace-points.
> >>>
> >>> We should look at each dprintf and check whenever it makes sense at all,
> >>> whenever it makes sense at that place before converting it over to a
> >>> tracepoint.
> > 
> > I'll also add qxl_spice_* trace points for the next patch. Does that
> > sound excessive? you could just trace the qxl_io_write to get the io
> > itself, or trace just qxl_spice_* to get the qxl<->spice interface, or
> > both (qxl_*).
> 
> Makes sense to place trace points systematically like that.
> 

What about having the frequent (read: too frequent to use stderr to dump
them since they clutter the screen, unless you 'stop' before each
monitor command) have a postfix "_freq"? This is a stopgap, but helpful
one, you can then do:
trace-event qxl* on
trace-event qxl*freq off

Instead of remembering / having conveniently ready a longer list:
trace-event qxl* on
trace-event qxl_interface_get_command_enter off
trace-event qxl_interface_release_resource off
trace-event qxl_interface_get_command_ret off
trace-event qxl_push_free_res off


> cheers,
>   Gerd
> 
>