Re: [PATCH] FUSE: Improve aio directIO write performance for size extending writes.

[Miklos Szeredi]

On Thu, Apr 7, 2016 at 1:48 PM, Ashish Sangwan <ashishsangwan2@xxxxxxxxx> wrote:
> While sending the blocking directIO in fuse, the write request is broken
> into sub-requests, each of default size 128k and all the requests are sent
> in non-blocking background mode if async_dio mode is supported by libfuse.
> The process which issue the write wait for the completion of all the
> sub-requests. Sending multiple requests parallely gives a chance to perform
> parallel writes in the user space fuse implementation if it is
> multi-threaded and hence improves the performance.
>
> When there is a size extending aio dio write, we switch to
> blocking mode so that we can properly update the size of the file after
> completion of the writes. However, in this situation all the sub-requests
> are sent in serialized manner where the next request is sent only after
> receiving the reply of the current request. Hence the multi-threaded user
> space implementation is not utilized properly.
>
> This patch changes the size extending aio dio behavior to exactly follow
> blocking dio. For multi threaded fuse implementation having 10 threads and
> using buffer size of 64MB to perform async directIO, we are getting double
> the speed.
>
> Signed-off-by: Ashish Sangwan <ashishsangwan2@xxxxxxxxx>

Thanks for you patience.  Pushed to

  git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git for-next

I simplified the logic, please verify that I didn't mess something up.

Thanks,
Miklos