Re: [dpdk-dev] [PATCH v5 1/2] app/testpmd: optimize testpmd txonly mode

[Thomas Monjalon <thomas@monjalon.net>]

02/04/2019 03:03, Jerin Jacob Kollanukkaran:
> On Mon, 2019-04-01 at 22:53 +0200, Thomas Monjalon wrote:
> > 01/04/2019 22:25, Ferruh Yigit:
> > > On 3/31/2019 2:14 PM, Pavan Nikhilesh Bhagavatula wrote:
> > > > From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > > > 
> > > > Optimize testpmd txonly mode by
> > > > 1. Moving per packet ethernet header copy above the loop.
> > > > 2. Use bulk ops for allocating segments instead of having a inner
> > > > loop
> > > > for every segment.
> > > > 
> > > > Also, move the packet prepare logic into a separate function so
> > > > that it
> > > > can be reused later.
> > > > 
> > > > Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > > > ---
> > > >  v5 Changes
> > > >  - Remove unnecessary change to struct rte_port *txp (movement).
> > > > (Bernard)
> > > > 
> > > >  v4 Changes:
> > > >  - Fix packet len calculation.
> > > > 
> > > >  v3 Changes:
> > > >  - Split the patches for easier review. (Thomas)
> > > >  - Remove unnecessary assignments to 0. (Bernard)
> > > > 
> > > >  v2 Changes:
> > > >  - Use bulk ops for fetching segments. (Andrew Rybchenko)
> > > >  - Fallback to rte_mbuf_raw_alloc if bulk get fails. (Andrew
> > > > Rybchenko)
> > > >  - Fix mbufs not being freed when there is no more mbufs
> > > > available for
> > > >  segments. (Andrew Rybchenko)
> > > 
> > > Hi Thomas, Shahafs,
> > > 
> > > I guess there was a performance issue on Mellanox with this patch,
> > > I assume it
> > > is still valid, since this version only has some cosmetic change,
> > > but can you
> > > please confirm?
> > 
> > We will check it.
> > 
> > > And what is the next step, can you guys provide some info to Pavan
> > > to solve the
> > > issue, or perhaps even better a fix?
> > 
> > Looking at the first patch, there are still 3 changes merged
> > together.
> > Why not splitting even more?
> 
> Splitting further more is not a issue. But we should not start the
> thread for squashing it patch latter. What would be interesting to know
> if there is any performance degradation with Mellanox NIC? If so, Why?
> Based on that, We can craft the patch as you need.

Regarding Mellanox degradation, we need to check if this is in this patch.

Not related to performance degradation, it is a good practice
to split logical changes of a rework.