Re: [dpdk-dev] [PATCH] examples/l3fwd: support separate buffer pool per port

["Ruifeng Wang (Arm Technology China)" <Ruifeng.Wang@arm.com>]

Hi Shreyansh,

> -----Original Message-----
> From: Shreyansh Jain <shreyansh.jain@nxp.com>
> Sent: Monday, April 15, 2019 14:48
> To: Ruifeng Wang (Arm Technology China) <Ruifeng.Wang@arm.com>;
> Ananyev, Konstantin <konstantin.ananyev@intel.com>; dev@dpdk.org
> Cc: nd <nd@arm.com>; nd <nd@arm.com>
> Subject: RE: [dpdk-dev] [PATCH] examples/l3fwd: support separate buffer
> pool per port
> 
> Hi Ruifeng,
> 
> [...]
> 
> > >
> > > For hardware backed pools, hardware access and exclusion are
> > expensive. By
> > > segregating pool/port/lcores it is possible to attain a conflict free
> > path. This is
> > > the use-case this patch targets.
> > > And anyways, this is an optional feature.
> > >
> > > > Konstantin
> > > >
> > > > > In dual core test, both modes had nearly same performance.
> > >
> > > OK
> > >
> > > > >
> > > > > My setup only has two ports which is limited.
> > > > > Just want to know the per-port-pool mode has more performance
> gain
> > > > when many ports are bound to  different cores?
> > >
> > > Yes, though not necessarily *many* - in my case, I had 4 ports and
> > even then
> > > about ~10% improvement was directly visible. I increased the port
> > count and
> > > I was able to touch about ~15%. I did pin each port to a separate
> > core, though.
> > > But again, important point is that without this feature enabled, I
> > didn't see
> > > any drop in performance. Did you observe any drop?
> > >
> >
> > No, no drop without the feature enabled in my test.
> 
> So, in case this is an optional feature, it should be fine, right?
> (Obviously, assuming that my logical implementation is correct)
> 
> At my end also, I saw no drop in performance without this feature (Default)
> and a decent increase with this (with separate port-core combination) on
> NXP platform.
> 
> [...]

Tested on LS2088A and observed 12% performance gain when 4 ports were used.
I think sample_app_ug document should be updated to add the new option.
Acked-by: Ruifeng Wang <ruifeng.wang@arm.com>

Regards,
/Ruifeng