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

[Ashish Sangwan]

On Thu, Jun 16, 2016 at 4:55 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
> 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.

The change looks ok.

>
> Thanks,
> Miklos