On 12/01/2015 04:04 AM, Avi Kivity wrote:
Sometimes you want to run a set of experiments on a disk, varying a parameter between tests (in my case, iodepth, but buffer size is also a good candidate). You then want to present the results in a nice graph. I wrote a small wrapper around fio to do this (https://github.com/avikivity/diskplorer), but it occurs to me that generalized support for both in fio would be much more useful. Possibly, you'd define a job as a template: [aio-read] template_start=1 template_end=100 template_step=1 (or template_ratio=1.05 for exponential growth) iodepth=template_variable (it's just possible that someone can come up with better syntax). A few more options in the global section can then cause a graph to be generated.
It'd be great to integrate this into fio, as graphing results is something that most people want to do. Any chance you would be willing to try and hash that out?
btw, a fast disk can easily saturate a single core using libaio, so a multithreaded libaio ioengine would be welcome (I am currently emulating it using multiple jobs and new_group).
In the context of fio, that doesn't make a lot of sense. A job in fio is, by definition, either a thread or a process that does IO. So if you want more threads banging on a device, then you'd add more jobs. If multiple threads shared on aio context, then we'd also potentially see contention on that part. If you just use more jobs, then each gets an aio context as well.
-- 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
