Re: [PATCH 0/5] nbd improvements

Re: [PATCH 0/5] nbd improvements

[Jens Axboe]

On 09/08/2016 01:33 PM, Josef Bacik wrote:
> This is a patch series aimed at bringing NBD into 2016.  The two big
> components of this series is converting nbd over to using blkmq and
> then allowing us to provide more than one connection for a nbd device.
> The NBD user space server doesn't care about how many connections it
> has to a particular device, so we can easily open multiple
> connections to the server and allow blkmq to handle multi-plexing over
> the different connections.  This drastically improves performance
> with multi-threaded workloads over NBD.  The multi-connection support
> requires some changes to the NBD userspace client code, and you can
> find that code here
>
> https://github.com/josefbacik/nbd
>
> I have been testing this for a few months and it is pretty solid and gives
> excellent performance improvements.  Thanks,

Not only are these nice performance improvements, it also cleans up the
code a lot and kills crufty old driver code in favor of using the proper
APIs instead. I have applied the series for 4.9.

-- 
Jens Axboe

Re: [Nbd] [PATCH 0/5] nbd improvements

[Wouter Verhelst]

Hi Jens,

On Thu, Sep 08, 2016 at 02:13:46PM -0600, Jens Axboe wrote:
> Not only are these nice performance improvements, it also cleans up the
> code a lot and kills crufty old driver code in favor of using the proper
> APIs instead. I have applied the series for 4.9.

Please ensure that the comments I made in my other mail are addressed
before you push this to Linus; otherwise this will result in significant
problems for userspace (that it would then be my responsibility to deal
with).

Thanks,

-- 
< ron> I mean, the main *practical* problem with C++, is there's like a dozen
       people in the world who think they really understand all of its rules,
       and pretty much all of them are just lying to themselves too.
 -- #debian-devel, OFTC, 2016-02-12

Re: [Nbd] [PATCH 0/5] nbd improvements

[Jens Axboe]

On 09/09/2016 02:08 PM, Wouter Verhelst wrote:
> Hi Jens,
>
> On Thu, Sep 08, 2016 at 02:13:46PM -0600, Jens Axboe wrote:
>> Not only are these nice performance improvements, it also cleans up the
>> code a lot and kills crufty old driver code in favor of using the proper
>> APIs instead. I have applied the series for 4.9.
>
> Please ensure that the comments I made in my other mail are addressed
> before you push this to Linus; otherwise this will result in significant
> problems for userspace (that it would then be my responsibility to deal
> with).

We've got some time to hash this out, before it goes upstream. I agree
on the 'pid' file being an issue, we need to bring that back to avoid
breaking userspace.

For the other part, Josef, did you test the multiple connection setup
against re-connection?

-- 
Jens Axboe

Re: [PATCH 0/5] nbd improvements

[Markus Pargmann]

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Hi Jens,

On 2016 M09 8, Thu 14:13:46 CEST Jens Axboe wrote:
> On 09/08/2016 01:33 PM, Josef Bacik wrote:
> > This is a patch series aimed at bringing NBD into 2016.  The two big
> > components of this series is converting nbd over to using blkmq and
> > then allowing us to provide more than one connection for a nbd device.
> > The NBD user space server doesn't care about how many connections it
> > has to a particular device, so we can easily open multiple
> > connections to the server and allow blkmq to handle multi-plexing over
> > the different connections.  This drastically improves performance
> > with multi-threaded workloads over NBD.  The multi-connection support
> > requires some changes to the NBD userspace client code, and you can
> > find that code here
> > 
> > https://github.com/josefbacik/nbd
> > 
> > I have been testing this for a few months and it is pretty solid and gives
> > excellent performance improvements.  Thanks,
> 
> Not only are these nice performance improvements, it also cleans up the
> code a lot and kills crufty old driver code in favor of using the proper
> APIs instead. I have applied the series for 4.9.

These patches conflict with the patches I picked up for 4.9 that fix the 
issues of dying filesystems on killed NBD block devices.
As I am a kernel hobbiest now, I had to move the git repository recently:
	https://github.com/scosu/linux-nbd

Best Regards,

Markus

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