diff mbox series

[net-next,v3,3/4] net: ocelot: pre-compute injection frame header content

Message ID 20211126172739.329098-4-clement.leger@bootlin.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Add FDMA support on ocelot switch driver | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/apply fail Patch does not apply to net-next

Commit Message

Clément Léger Nov. 26, 2021, 5:27 p.m. UTC
IFH preparation can take quite some time on slow processors (up to 5% in
a iperf3 test for instance). In order to reduce the cost of this
preparation, pre-compute IFH since most of the parameters are fixed per
port. Only rew_op and vlan tag will be set when sending if different
than 0. This allows to remove entirely the calls to packing() with basic
usage. In the same time, export this function that will be used by FDMA.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
---
 drivers/net/ethernet/mscc/ocelot.c | 23 ++++++++++++++++++-----
 include/soc/mscc/ocelot.h          |  5 +++++
 2 files changed, 23 insertions(+), 5 deletions(-)

Comments

Vladimir Oltean Nov. 26, 2021, 5:54 p.m. UTC | #1
On Fri, Nov 26, 2021 at 06:27:38PM +0100, Clément Léger wrote:
> IFH preparation can take quite some time on slow processors (up to 5% in
> a iperf3 test for instance). In order to reduce the cost of this
> preparation, pre-compute IFH since most of the parameters are fixed per
> port. Only rew_op and vlan tag will be set when sending if different
> than 0. This allows to remove entirely the calls to packing() with basic
> usage. In the same time, export this function that will be used by FDMA.
> 
> Signed-off-by: Clément Léger <clement.leger@bootlin.com>
> ---

If you would move this injection frame header template into struct
ocelot_port_private instead of struct ocelot_port, I would not have
anything against it. Because struct ocelot_port is common with DSA,
whereas struct ocelot_port_private isn't.

Also, as things stand, all switch drivers call ocelot_init_port, but not
all supported switches have the same IFH format. See seville_xmit() ->
seville_ifh_set_dest(). So even though DSA does not use this for
anything, it wouldn't even contain valid information even if it wanted
to. So maybe you can move this initialization to some place isolated to
vsc7514.
Clément Léger Nov. 26, 2021, 5:57 p.m. UTC | #2
Le Fri, 26 Nov 2021 17:54:55 +0000,
Vladimir Oltean <vladimir.oltean@nxp.com> a écrit :

> On Fri, Nov 26, 2021 at 06:27:38PM +0100, Clément Léger wrote:
> > IFH preparation can take quite some time on slow processors (up to 5% in
> > a iperf3 test for instance). In order to reduce the cost of this
> > preparation, pre-compute IFH since most of the parameters are fixed per
> > port. Only rew_op and vlan tag will be set when sending if different
> > than 0. This allows to remove entirely the calls to packing() with basic
> > usage. In the same time, export this function that will be used by FDMA.
> > 
> > Signed-off-by: Clément Léger <clement.leger@bootlin.com>
> > ---  
> 
> If you would move this injection frame header template into struct
> ocelot_port_private instead of struct ocelot_port, I would not have
> anything against it. Because struct ocelot_port is common with DSA,
> whereas struct ocelot_port_private isn't.
> 
> Also, as things stand, all switch drivers call ocelot_init_port, but not
> all supported switches have the same IFH format. See seville_xmit() ->
> seville_ifh_set_dest(). So even though DSA does not use this for
> anything, it wouldn't even contain valid information even if it wanted
> to. So maybe you can move this initialization to some place isolated to
> vsc7514.

Acked, this makes sense, I will do this.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index e6c18b598d5c..1f7c9ff18ac5 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1076,20 +1076,29 @@  bool ocelot_can_inject(struct ocelot *ocelot, int grp)
 }
 EXPORT_SYMBOL(ocelot_can_inject);
 
+void ocelot_ifh_port_set(void *ifh, struct ocelot_port *ocelot_port, u32 rew_op,
+			 u32 vlan_tag)
+{
+	memcpy(ifh, ocelot_port->ifh, OCELOT_TAG_LEN);
+
+	if (vlan_tag)
+		ocelot_ifh_set_vlan_tci(ifh, vlan_tag);
+	if (rew_op)
+		ocelot_ifh_set_rew_op(ifh, rew_op);
+}
+EXPORT_SYMBOL(ocelot_ifh_port_set);
+
 void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 			      u32 rew_op, struct sk_buff *skb)
 {
+	struct ocelot_port *ocelot_port = ocelot->ports[port];
 	u32 ifh[OCELOT_TAG_LEN / 4] = {0};
 	unsigned int i, count, last;
 
 	ocelot_write_rix(ocelot, QS_INJ_CTRL_GAP_SIZE(1) |
 			 QS_INJ_CTRL_SOF, QS_INJ_CTRL, grp);
 
-	ocelot_ifh_set_bypass(ifh, 1);
-	ocelot_ifh_set_dest(ifh, BIT_ULL(port));
-	ocelot_ifh_set_tag_type(ifh, IFH_TAG_TYPE_C);
-	ocelot_ifh_set_vlan_tci(ifh, skb_vlan_tag_get(skb));
-	ocelot_ifh_set_rew_op(ifh, rew_op);
+	ocelot_ifh_port_set(ifh, ocelot_port, rew_op, skb_vlan_tag_get(skb));
 
 	for (i = 0; i < OCELOT_TAG_LEN / 4; i++)
 		ocelot_write_rix(ocelot, ifh[i], QS_INJ_WR, grp);
@@ -2128,6 +2137,10 @@  void ocelot_init_port(struct ocelot *ocelot, int port)
 
 	skb_queue_head_init(&ocelot_port->tx_skbs);
 
+	ocelot_ifh_set_bypass(ocelot_port->ifh, 1);
+	ocelot_ifh_set_dest(ocelot_port->ifh, BIT_ULL(port));
+	ocelot_ifh_set_tag_type(ocelot_port->ifh, IFH_TAG_TYPE_C);
+
 	/* Basic L2 initialization */
 
 	/* Set MAC IFG Gaps
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index fef3a36b0210..b3381c90ff3e 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -6,6 +6,7 @@ 
 #define _SOC_MSCC_OCELOT_H
 
 #include <linux/ptp_clock_kernel.h>
+#include <linux/dsa/ocelot.h>
 #include <linux/net_tstamp.h>
 #include <linux/if_vlan.h>
 #include <linux/regmap.h>
@@ -623,6 +624,8 @@  struct ocelot_port {
 
 	struct net_device		*bridge;
 	u8				stp_state;
+
+	u8				ifh[OCELOT_TAG_LEN];
 };
 
 struct ocelot {
@@ -754,6 +757,8 @@  void __ocelot_target_write_ix(struct ocelot *ocelot, enum ocelot_target target,
 bool ocelot_can_inject(struct ocelot *ocelot, int grp);
 void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 			      u32 rew_op, struct sk_buff *skb);
+void ocelot_ifh_port_set(void *ifh, struct ocelot_port *port, u32 rew_op,
+			 u32 vlan_tag);
 int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp, struct sk_buff **skb);
 void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp);