Re: [Qemu-devel] [PATCH 5/9] log: improve performance of qemu_log and qemu_log_mask if disabled

[Denis V. Lunev]

On 03/14/2016 05:30 PM, Paolo Bonzini wrote:
> On 14/03/2016 12:21, Denis V. Lunev wrote:
> > The patch is intended to avoid to perform any operation including
> > calculation of log function arguments when the log is not enabled due to
> > various reasons.
> >
> > Functions qemu_log and qemu_log_mask are replaced with variadic macros.
> >
> > Format checking performed by compiler will not suffer by this patch. It
> > will be done inside in fprintf arguments checking.
> Have you encountered a place that was calling them so hard that it
> caused performance problem?  If so, the logging should probably be
> replaced by a tracepoint.
>
> Paolo

inline functions can have side-effects, i.e. the arguments of them
can be evaluated depending on the compiler. with this approach
we are sure that this will not happen, ever.

Den