On 08/14/2012 08:24 AM, Greg Sullivan wrote: > I need to simulate strict synchronous, round robin i/o to a group of > files. I am on Windows 7 32-bit. > fio is very nearly working, except that even with a queue depth of 1, > it is still resulting in a disk queue that is > 1, because the > "iodepth" parameter is not global - it is per thread. (correct?) > > I've tried using the "sync" engine, however that doesn't work at all - > just spews out errors. That'll be the case for ANY platform and IO engine. If you have more than 1 thread or process going, you can have > 1 depth at the device side. The definition of a sync IO call is that the call doesn't return until the IO is done. If you have overlapped calls due to more than 1 thread, then that is no longer true. What you are looking for is outside the scope of an application. You would have to limit the queue depth on the operating system side to achieve that. Or artificially limit fio in some way, which would not make a lot of sense imho. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
