Vladimir Sementsov-Ogievskiy writes:
Current trace system have a drawback: parameters of trace functions
are calculated even if corresponding tracepoint is disabled. Also, it
looks like trace function are not actually inlined by compiler (at
least for me).
Here is a fix proposal: move from function call to macros. Patch 02
is an example, of how to reduce extra calculations with help of
patch 01.
The tracing functions *were* inlined last time I checked, although things
changed quite a lot since then. Not sure that will make a lot of difference in
terms of overall performance (needs measuring).
As for arguments, each trace event has a define TRACE_{NAME}_ENABLED that you
can use for that purpose. If this is not explained in tracing.txt, that is a
documentation bug.