int eprintf(int level, int var, const char *fmt, ...) __attribute__((format(printf, 3, 4)));
int eprintf_time(int level, int var, u64 t, const char *fmt, ...) __attribute__((format(printf, 4, 5)));
+int veprintf(int level, int var, const char *fmt, va_list args);
int perf_debug_option(const char *str);