On Fri, Nov 06, 2015 at 05:10:07PM +0000, Bruce Richardson wrote:
> On Thu, Nov 05, 2015 at 04:09:18PM +0100, Adrien Mazarguil wrote:
> >
> > I won't argue against this as it's obviously more complex than the original
> > method, however note that users of the RTE_PMD_DEBUG_TRACE() macro do not
> > have to modify their code. They shouldn't care about the implementation.
> >
> > Also note that we can do much cleaner code if we drop the all macros
> > implementation using a (much easier to debug) static inline function,
> > only perhaps with a wrapper macro that provides __LINE__, __func__ and
> > __FILE__ as arguments. Nontrival code shouldn't be done in macros anyway.
> >
> Getting something working with __FILE__ and probably __LINE__ would be easy
> enough
> with a helper macro, but __func__ is not so easy as it's not a preprocessor
> symbol
> [since the pre-processor has no idea what function you are in].
>
> However, using func, here is the best I've come up with so far. It's not that
> pretty, but it's probably easier to work with than the macro version.
>
> #ifdef RTE_LIBRTE_ETHDEV_DEBUG
> -#define RTE_PMD_DEBUG_TRACE(fmt, args...) \
> - RTE_LOG(ERR, PMD, "%s: " fmt, __func__, ## args)
> +#define RTE_PMD_DEBUG_TRACE(...) \
> + rte_pmd_debug_trace(__func__, __VA_ARGS__)
> +
> +static inline void
> +rte_pmd_debug_trace(const char *func_name, const char *fmt, ...)
> +{
> + static __thread char buffer[128];
> + char *out_buf = buffer;
> + unsigned count;
> + va_list ap;
> +
> + count = snprintf(buffer, sizeof(buffer), "%s: %s", func_name, fmt);
> + if (count >= sizeof(buffer)) { // truncated output
> + char *new_buf = malloc(count + 1);
> + if (new_buf == NULL) // no memory, just print 128 chars
> + goto print_buffer;
> + snprintf(new_buf, count + 1, "%s: %s", func_name, fmt);
> + va_start(ap, fmt);
> + rte_vlog(RTE_LOG_ERR, RTE_LOGTYPE_PMD, buffer, ap);
> + va_end(ap);
> + free(new_buf);
> + return;
> + }
> +
> +print_buffer:
> + va_start(ap, fmt);
> + rte_vlog(RTE_LOG_ERR, RTE_LOGTYPE_PMD, out_buf, ap);
> + va_end(ap);
> +}
> #else
> #define RTE_PMD_DEBUG_TRACE(fmt, args...)
> #endif
>
> Comments or improvements?
>
> /Bruce
And here's the version if we are happy to have file and line number instead of
function name. I think this might be the best option.
/Bruce
#ifdef RTE_LIBRTE_ETHDEV_DEBUG
-#define RTE_PMD_DEBUG_TRACE(fmt, args...) \
- RTE_LOG(ERR, PMD, "%s: " fmt, __func__, ## args)
+#define RTE_PMD_DEBUG_TRACE(...) \
+ RTE_LOG(ERR, PMD, __FILE__", " RTE_STR(__LINE__) ": " __VA_ARGS__)
#else
-#define RTE_PMD_DEBUG_TRACE(fmt, args...)
+#define RTE_PMD_DEBUG_TRACE(...)
#endif
