Re: [Lsf-pc] [LSF/MM TOPIC] async buffered diskio read for userspace apps

[Jens Axboe <axboe@kernel.dk>]

On 01/19/2015 07:18 AM, Milosz Tanski wrote:
> On Mon, Jan 19, 2015 at 2:34 AM, James Bottomley
> <James.Bottomley@hansenpartnership.com> wrote:
>> On Sun, 2015-01-18 at 23:12 -0800, Jeremy Allison wrote:
>>> On Sun, Jan 18, 2015 at 10:49:36PM -0500, Milosz Tanski wrote:
>>>>
>>>> I have the first version of the FIO cifs support via samba in my fork
>>>> of FIO here: https://github.com/mtanski/fio/tree/samba
>>>>
>>>> Right now it only supports sync mode of FIO (eg. can't submit multiple
>>>> outstanding requests) but I'm looking into how to make it work with
>>>> smb2 read/write calls with the async flag.
>>>>
>>>> Additionally, I'm sure I'm doing some things not quite right in terms
>>>> of smbcli usage as it was a decent amount of trial and error to get it
>>>> to connect (esp. the setup before smbcli_full_connection). Finally, it
>>>> looks like the more complex api I'm using (as opposed to smbclient,
>>>> because I want the async calls) doesn't quite fully export all calls I
>>>> need via headers / public dyn libs so it's a bit of a hack to get it
>>>> to build: https://github.com/mtanski/fio/commit/7fd35359259b409ed023b924cb2758e9efb9950c#diff-1
>>>>
>>>> But it works for my randread tests with zipf and the great part is
>>>> that it should provide a flexible way to test samba with many fake
>>>> clients and access patterns. So... progress.
>>>
>>> One problem here. Looks like fio is under GPLv2-only,
>>> is that correct ?
>>
>> Seems so from the LICENSE file.
>>
>>> If so there's no way to combine the two codebases,
>>> as Samba is under GPLv3-or-later with parts under LGPLv3-or-later.
>>>
>>> fio needs to be GPLv2-or-later in order to be
>>> able to use with libsmbclient.
>>
>> That's one of these pointless licensing complexities that annoy
>> distributions so much ... they're both open source, so there's no real
>> problem except the licence incompatibility. The usual way out of it is
>> just to dual licence the incompatible component.
>>
>> James
>>
>>
>
> Sadly, in this case there's nothing I can do about the license; both
> projects have a right to determine their own licensing. Hopefully, the
> parties can come to some kind of agreement since it would be
> beneficial to use fio to test samba.
>
> This works well enough for me to test test preadv2 using samba and get
> numbers. So I'll use this to do some preadv2 testing using samba for
> different workloads.

I didn't look at your code yet, but I'm assuming it's a self contained 
IO engine. So we should be able to make that work, by only linking the 
engine itself against libsmbclient. But sheesh, what a pain in the butt, 
why can't we just all be friends.

So don't worry about licensing for now, just work on improving the 
engine and we'll sort the non-technical details out.

-- 
Jens Axboe