[PATCH net-next 0/2] net: mvpp2: Add txq to CPU mapping

Hi everyone,

This short series adds XPS support to the mvpp2 driver, by mapping
txqs and CPUs. This comes with a patch using round-robin scheduling
for the HW to pick the next txq to transmit from, instead of the default
fixed-priority scheduling.

Maxime Chevallier (2):
  net: mvpp2: support XPS by mapping TX queues to CPUs
  net: mvpp2: use round-robin scheduling for TX queues on the same CPU

 drivers/net/ethernet/marvell/mvpp2/mvpp2.h      | 1 +
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

-- 
2.11.0

Since the PPv2 controller has multiple TX queues, we can spread traffic
by assining TX queues to CPUs, allowing to use XPS to balance egress
traffic between CPUs.

Suggested-by : Yan Markman [off-list ref]
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index d30ccc515bb7..bdacb9577216 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

@@ -2423,13 +2423,17 @@ static int mvpp2_setup_rxqs(struct mvpp2_port *port)
 static int mvpp2_setup_txqs(struct mvpp2_port *port)
 {
 	struct mvpp2_tx_queue *txq;
-	int queue, err;
+	int queue, err, cpu;
 
 	for (queue = 0; queue < port->ntxqs; queue++) {
 		txq = port->txqs[queue];
 		err = mvpp2_txq_init(port, txq);
 		if (err)
 			goto err_cleanup;
+
+		/* Assign this queue to a CPU */
+		cpu = queue % num_present_cpus();
+		netif_set_xps_queue(port->dev, cpumask_of(cpu), queue);
 	}
 
 	if (port->has_tx_irqs) {

-- 
2.11.0

This commit allows each TXQ to be picked in a round-robin fashion by
the PPv2 transmit scheduling mechanism. This is opposed to the default
behaviour that prioritizes the highest numbered queues.

Suggested-by: Yan Markman <redacted>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2.h      | 1 +
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
index f5dceef60b0e..176c6b56fdcc 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h

@@ -331,6 +331,7 @@
 #define     MVPP2_TXP_SCHED_ENQ_MASK		0xff
 #define     MVPP2_TXP_SCHED_DISQ_OFFSET		8
 #define MVPP2_TXP_SCHED_CMD_1_REG		0x8010
+#define MVPP2_TXP_SCHED_FIXED_PRIO_REG		0x8014
 #define MVPP2_TXP_SCHED_PERIOD_REG		0x8018
 #define MVPP2_TXP_SCHED_MTU_REG			0x801c
 #define     MVPP2_TXP_MTU_MAX			0x7FFFF

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index bdacb9577216..c2ed71788e4f 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

@@ -1448,6 +1448,9 @@ static void mvpp2_defaults_set(struct mvpp2_port *port)
 		    tx_port_num);
 	mvpp2_write(port->priv, MVPP2_TXP_SCHED_CMD_1_REG, 0);
 
+	/* Set TXQ scheduling to Round-Robin */
+	mvpp2_write(port->priv, MVPP2_TXP_SCHED_FIXED_PRIO_REG, 0);
+
 	/* Close bandwidth for all queues */
 	for (queue = 0; queue < MVPP2_MAX_TXQ; queue++) {
 		ptxq = mvpp2_txq_phys(port->id, queue);

-- 
2.11.0

From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: Mon, 24 Sep 2018 11:11:04 +0200

This short series adds XPS support to the mvpp2 driver, by mapping
txqs and CPUs. This comes with a patch using round-robin scheduling
for the HW to pick the next txq to transmit from, instead of the default
fixed-priority scheduling.

Series applied, thanks Maxime.