Re: [PATCH 1/6] dma/pl330: Convert to support tracing

[Guenter Roeck]

On Fri, Jan 17, 2020 at 05:05:07PM +0000, Peter Maydell wrote:
> On Fri, 17 Jan 2020 at 16:46, Guenter Roeck <address@hidden> wrote:
> >
> > On Fri, Jan 17, 2020 at 01:23:46PM +0000, Peter Maydell wrote:
> > > Won't this now do all the work of constructing the hexdump strings,
> > > even if tracing is disabled ?
> > >
> > That is correct. Can I check
> >         if (trace_event_get_state(TRACE_PL330_HEXDUMP) &&
> >             qemu_loglevel_mask(LOG_TRACE)) {
> > directly in pl330_hexdump(), or is there some other means to handle
> > this kind of situation ?
> 
> It's not something I've had to do before.
> docs/devel/tracing.txt says "just use the TRACE_FOO_ENABLED
> macro", but looking at what it does that doesn't seem to check
> the runtime state of the trace event, so maybe those docs are out
> of date. Stefan, what's the current best way to guard expensive
> computations used only for trace output ?
> 
trace_event_get_state_backends(TRACE_PL330_HEXDUMP), maybe ?

Thanks,
Guenter