RE: [PATCH] examples/l3fwd-graph: remove redundant Tx queue limit

[Konstantin Ananyev <konstantin.ananyev@huawei.com>]

> On Mon, Sep 1, 2025 at 11:39 PM Sivaprasad Tummala
> <sivaprasad.tummala@amd.com> wrote:
> >
> > In `l3fwd-graph` application, Tx queues are configured per lcore
> > to enable a lockless design and achieve optimal performance.
> >
> > The `MAX_TX_QUEUE_PER_PORT` macro, defined as `RTE_MAX_ETHPORTS`,
> > introduced an artificial constraint on the number of Tx queues
> > and limited core-scaling performance.
> >
> > This patch removes the unused `MAX_TX_QUEUE_PER_PORT` macro and
> > redundant Tx queue check, allowing Tx queues to scale directly
> > with the no. of lcores.
> >
> > Fixes: 08bd1a174461 ("examples/l3fwd-graph: add graph-based l3fwd skeleton")
> > Cc: ndabilpuram@marvell.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Sivaprasad Tummala <sivaprasad.tummala@amd.com>
> > ---
> >  examples/l3fwd-graph/main.c | 3 ---
> >  1 file changed, 3 deletions(-)
> >
> > diff --git a/examples/l3fwd-graph/main.c b/examples/l3fwd-graph/main.c
> > index 92cdaa1ebe..12908acbba 100644
> > --- a/examples/l3fwd-graph/main.c
> > +++ b/examples/l3fwd-graph/main.c
> > @@ -49,7 +49,6 @@
> >  #define RX_DESC_DEFAULT 1024
> >  #define TX_DESC_DEFAULT 1024
> >
> > -#define MAX_TX_QUEUE_PER_PORT RTE_MAX_ETHPORTS
> >  #define MAX_RX_QUEUE_PER_PORT 128

AFAIK, in the mainline we actually have:
#define MAX_TX_QUEUE_PER_PORT RTE_MAX_LCORE

since:
commit 88256ed85338c572d73006e4c4530a52d3b477ff
Author: Harman Kalra <hkalra@marvell.com>
Date:   Tue Jan 12 23:54:46 2021 +0530

    examples/l3fwd: remove limitation on Tx queue count

What I am missing here?

> >
> >  #define MAX_RX_QUEUE_PER_LCORE 16
> > @@ -1076,8 +1075,6 @@ main(int argc, char **argv)
> >
> >                 nb_rx_queue = get_port_n_rx_queues(portid);
> >                 n_tx_queue = nb_lcores;
> > -               if (n_tx_queue > MAX_TX_QUEUE_PER_PORT)
> > -                       n_tx_queue = MAX_TX_QUEUE_PER_PORT;
> >                 printf("Creating queues: nb_rxq=%d nb_txq=%u... ",
> >                        nb_rx_queue, n_tx_queue);
> >
> > --
> > 2.43.0
> >