fio: better info when engine not found

Jens suggested we provide the user with the likely reasons why we failed
to load the given engine.
This should help better resolve these issues.

Signed-off-by: Yigal Korman <ykorman@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/ioengines.c b/ioengines.c
index 78262bc1a3c70484701345e524f17fb06e60870e..c1b430a1722bfd2ee5f7566bbcf5775b413cd472 100644 (file)
--- a/ioengines.c
+++ b/ioengines.c
@@ -79,10 +79,16 @@ static struct ioengine_ops *find_ioengine(const char *name)
 static void *dlopen_external(struct thread_data *td, const char *engine)
 {
        char engine_path[PATH_MAX];
+       void *dlhandle;
 
        sprintf(engine_path, "%s/lib%s.so", FIO_EXT_ENG_DIR, engine);
 
-       return dlopen(engine_path, RTLD_LAZY);
+       dlhandle = dlopen(engine_path, RTLD_LAZY);
+       if (!dlhandle)
+               log_info("Engine %s not found; Either name is invalid, was not built, or fio-engine-%s package is missing.\n",
+                        engine, engine);
+
+       return dlhandle;
 }
 #else
 #define dlopen_external(td, engine) (NULL)