Re: [dpdk-dev] [PATCH 0/2] Native uio-based PMD for Mellanox ConnectX-3 devices

[Olga Shern <olgas@mellanox.com>]

Hi Keunhong, 

I disagree with you regarding the performance of ConnectX-3 PMD driver based on verbs. We get line rate of 40G link with message size smaller than 512B.
In MLNX_OFED 3.0 we have presented a new verbs, called accelerated verbs, these verbs improves by more than 100% the performance of RAW QP for DPDK.  The PMD changes based on this new infrastructure have been submitted to this list and are  part of DPDK 2.1 release.
Our approach is to improve performance of userspace verbs then to maintain a huge amount of code that you have submitted.
    
Another advantage to use userspace  verbs API is  that you have so called bi-furcated driver by design. Kernel driver can work side by side with DPDK PMD , if needed, and there is no security issues with this model.

Best Regards,
Olga


________________________________________________________________
Olga Shern 
Sr. Manager, Acceleration libraries team (Accelio, DPDK, VMA) 
Mellanox Technologies, Raanana Israel



-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Keunhong Lee
Sent: Monday, July 06, 2015 8:56 PM
To: Thomas Monjalon
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 0/2] Native uio-based PMD for Mellanox ConnectX-3 devices

We found that optimizing fragmentation configuration of mlx4 driver performs as fast as native PMD.
I think we have to re-consider using native driver rather than ib driver.

Keunhong.

2015-07-07 1:14 GMT+09:00 Thomas Monjalon <thomas.monjalon@6wind.com>:

> 2015-07-07 00:57, Keunhong Lee:
> > Answer 1. UIO based driver is faster then ib based driver.
> > It can saturate 40G link with MTU sized packets using a single 
> > thread
> while
> > ib wrapper cannot.
>
> OK, interesting. Do you have numbers and details about your 
> testbed/scenario?
>
> > Answer 2. Sorry, I missed that. I'll make a new patch email with my 
> > real name.
> >
> > Question 1. Is it OK if I separate GPL-based and BSD-based codes 
> > into separated patches?
> > mlx4 kernel driver itself is dual licenses, so I think they are
> considered
> > as BSD in my source code.
> > The only source code under GPL is bitmap, integer logarithm, and
> red-black
> > tree contained in mlnx_uio/kernel directory.
>
> These parts will be built in the user-space driver library, right?
> It would change the license, which is not desirable.
>
> Technically, your approach may be interesting.
> But from a maintenance point of view, this huge codebase may be a 
> nightmare.
>
>
> > 2015-07-06 23:17 GMT+09:00 Thomas Monjalon <thomas.monjalon@6wind.com>:
> >
> > > 2015-07-06 22:28, leeopop:
> > > > This is a native UIO-based PMD for Mellanox ConnectX-3 devices.
> > > > It uses a persistent memory library in order to provide a 
> > > > persistent scartch area for the mlx4 HCA driver.
> > >
> > > What is the benefit of this UIO approach compared to the OFED 
> > > based
> driver?
> > >
> > > > We release the driver itself under BSD license, but to use it 
> > > > for commercial products, you may have to re-implement the 
> > > > separated GPL sources.
> > >
> > > The GPL sources are not really separated.
> > > The DPDK libraries must be BSD-licensed.
> > >
> > > > The GPL affected source codes reside in the mlnx_uio/kernel
> directory.
> > >
> > > It seems that a large part of the GPL driver was also copied in 
> > > mlnx_uio/mlnx/.
> > >
> > > Given that you are dropping a huge GPL codebase (whose you don't 
> > > own
> the
> > > copyright) in a BSD library, and that you didn't give your real 
> > > name in the signed-off line, it is NACK.
>
>
>
>