[dpdk-users] General Questions

[dpdk-users] General Questions

[Cristofer Martins]

Well the reason i thought about using dpdk(together with a user space tcp stack) is because my tcp code spend so much time with syscalls that removing that would allow better throughput and latency. Is this a valid reason? My software runs in single core(and most of time in cheap vps) so i want to extract the best i can from them.
The other question is, can dpdk runs alongside with the linux network stack? I want to use dpdk in my special app but i still want to have ssh and apps working as expected without any modification.

Thanks in advance.

Re: [dpdk-users] General Questions

[Stephen Hemminger]

On Thu, 9 Apr 2020 06:11:28 +0000
Cristofer Martins <CristoferMartins@hotmail.com> wrote:

> Well the reason i thought about using dpdk(together with a user space tcp stack) is because my tcp code spend so much time with syscalls that removing that would allow better throughput and latency. Is this a valid reason? My software runs in single core(and most of time in cheap vps) so i want to extract the best i can from them.
> The other question is, can dpdk runs alongside with the linux network stack? I want to use dpdk in my special app but i still want to have ssh and apps working as expected without any modification.
> 
> Thanks in advance.
> 

If you are doing syscalls in your DPDK application, then you are defeating the point
of DPDK and you are better off using the kernel networking stack.

Re: [dpdk-users] General Questions

[Shyam Shrivastav]

From my experience as dpdk user

On Thu, Apr 9, 2020 at 11:41 AM Cristofer Martins <
CristoferMartins@hotmail.com> wrote:

> Well the reason i thought about using dpdk(together with a user space tcp
> stack) is because my tcp code spend so much time with syscalls that
> removing that would allow better throughput and latency. Is this a valid
> reason? My software runs in single core(and most of time in cheap vps) so i
> want to extract the best i can from them.
>

Yes using dpdk instead of getting packets from kernel stack increases
performance



> The other question is, can dpdk runs alongside with the linux network
> stack? I want to use dpdk in my special app but i still want to have ssh
> and apps working as expected without any modification.
>
Interface used by dpdk is not available, at least another interface
required for management/access &  other network apps



>
> Thanks in advance.
>

Re: [dpdk-users] General Questions

[Stephen Hemminger]

On Thu, 9 Apr 2020 20:57:19 +0530
Shyam Shrivastav <shrivastav.shyam@gmail.com> wrote:

> From my experience as dpdk user
> 
> On Thu, Apr 9, 2020 at 11:41 AM Cristofer Martins <
> CristoferMartins@hotmail.com> wrote:  
> 
> > Well the reason i thought about using dpdk(together with a user space tcp
> > stack) is because my tcp code spend so much time with syscalls that
> > removing that would allow better throughput and latency. Is this a valid
> > reason? My software runs in single core(and most of time in cheap vps) so i
> > want to extract the best i can from them.
> >  
> 
> Yes using dpdk instead of getting packets from kernel stack increases
> performance
> 
> 
> 
> > The other question is, can dpdk runs alongside with the linux network
> > stack? I want to use dpdk in my special app but i still want to have ssh
> > and apps working as expected without any modification.
> >  
> Interface used by dpdk is not available, at least another interface
> required for management/access &  other network apps
> 
> 
> 
> >
> > Thanks in advance.
> >  

This might be a good use case for AF_XDP with or without DPDK

Re: [dpdk-users] General Questions

[Thomas Monjalon]

09/04/2020 17:32, Stephen Hemminger:
> On Thu, 9 Apr 2020 20:57:19 +0530
> Shyam Shrivastav <shrivastav.shyam@gmail.com> wrote:
> 
> > From my experience as dpdk user
> > 
> > On Thu, Apr 9, 2020 at 11:41 AM Cristofer Martins <
> > CristoferMartins@hotmail.com> wrote:  
> > 
> > > Well the reason i thought about using dpdk(together with a user space tcp
> > > stack) is because my tcp code spend so much time with syscalls that
> > > removing that would allow better throughput and latency. Is this a valid
> > > reason? My software runs in single core(and most of time in cheap vps) so i
> > > want to extract the best i can from them.
> > >  
> > 
> > Yes using dpdk instead of getting packets from kernel stack increases
> > performance
> > 
> > 
> > 
> > > The other question is, can dpdk runs alongside with the linux network
> > > stack? I want to use dpdk in my special app but i still want to have ssh
> > > and apps working as expected without any modification.
> > >  
> > Interface used by dpdk is not available, at least another interface
> > required for management/access &  other network apps
> > 
> > 
> > 
> > >
> > > Thanks in advance.
> > >  
> 
> This might be a good use case for AF_XDP with or without DPDK

AF_XDP helps to use a device both with Linux stack and userland application.
This capability is what we call the bifurcated model.
The Mellanox drivers are also using a bifurcated model:
the same device can send some packet flows to the kernel interface,
and other (configured) packet flows to the DPDK interface.