zhhyu7 opened a new pull request, #17660:
URL: https://github.com/apache/nuttx/pull/17660
## Summary
Avoid packet processing delays caused by task switching, to support those
applications that are extremely time-sensitive.
Has a very obvious positive effect on CAN communication.
## Impact
lowerhalf net device driver.
If the network card does not call netdev_lower_rxready during an interrupt,
rxtype can be configured as NETDEV_RX_DIRECT, which will reduce one thread
context switch in the packet reception process, thereby reducing latency and
CPU load.
## Testing
sim:matter with ping and iperf
change in nuttx/arch/sim/src/sim/sim_netdriver.c
```
diff --git a/arch/sim/src/sim/sim_netdriver.c
b/arch/sim/src/sim/sim_netdriver.c
index de298f81edb..87dfd78342f 100644
--- a/arch/sim/src/sim/sim_netdriver.c
+++ b/arch/sim/src/sim/sim_netdriver.c
@@ -99,6 +99,8 @@
struct sim_netdev_s
{
struct netdev_lowerhalf_s dev;
+ struct work_s rxworker;
+ struct work_s txworker;
uint8_t buf[SIM_NETDEV_BUFSIZE]; /* Used when packet buffer is fragmented
*/
};
#endif
@@ -220,18 +222,30 @@ static int netdriver_ifdown(struct netdev_lowerhalf_s
*dev)
return OK;
}
-static void netdriver_txdone_interrupt(void *priv)
+static void netdriver_txdone_handle(void *priv)
{
struct netdev_lowerhalf_s *dev = (struct netdev_lowerhalf_s *)priv;
netdev_lower_txdone(dev);
}
-static void netdriver_rxready_interrupt(void *priv)
+static void netdriver_txdone_interrupt(void *priv)
+{
+ struct sim_netdev_s *dev = (struct sim_netdev_s *)priv;
+ work_queue(HPWORK, &dev->txworker, netdriver_txdone_handle, priv, 0);
+}
+
+static void netdriver_rxready_handle(void *priv)
{
struct netdev_lowerhalf_s *dev = (struct netdev_lowerhalf_s *)priv;
netdev_lower_rxready(dev);
}
+static void netdriver_rxready_interrupt(void *priv)
+{
+ struct sim_netdev_s *dev = (struct sim_netdev_s *)priv;
+ work_queue(HPWORK, &dev->rxworker, netdriver_rxready_handle, priv, 0);
+}
+
/****************************************************************************
* Public Functions
****************************************************************************/
@@ -256,6 +270,7 @@ int sim_netdriver_init(void)
dev->quota[NETPKT_TX] = 1;
dev->quota[NETPKT_RX] = 1;
dev->ops = &g_ops;
+ dev->rxtype = NETDEV_RX_DIRECT;
#if CONFIG_SIM_WIFIDEV_NUMBER != 0
if (devidx < CONFIG_SIM_WIFIDEV_NUMBER)
```
test log
```
NuttShell (NSH) NuttX-12.11.0
MOTD: username=admin password=Administrator
nsh> ifconfig eth0 10.0.1.2/24
nsh> ifconfig
eth0 Link encap:Ethernet HWaddr 42:e1:c4:3f:48:dd at RUNNING mtu 1500
inet addr:10.0.1.2 DRaddr:10.0.1.1 Mask:255.255.255.0
inet6 addr: fe80::40e1:c4ff:fe3f:48dd/64
inet6 DRaddr: ::
nsh> ping -c 3 10.0.1.1
PING 10.0.1.1 56 bytes of data
56 bytes from 10.0.1.1: icmp_seq=0 time=0.0 ms
56 bytes from 10.0.1.1: icmp_seq=1 time=0.0 ms
56 bytes from 10.0.1.1: icmp_seq=2 time=0.0 ms
3 packets transmitted, 3 received, 0% packet loss, time 3030 ms
rtt min/avg/max/mdev = 0.000/0.000/0.000/0.000 ms
nsh> iperf -c 10.0.1.1
ERROR: access IP is 0x00
nsh> iperf -c 10.0.1.1 -B 10.0.1.2
IP: 10.0.1.2
mode=tcp-client sip=10.0.1.2:5001,dip=10.0.1.1:5001, interval=3, time=30
Interval Transfer Bandwidth
0.00- 7.35 sec 450871296 Bytes 490.74 Mbits/sec
7.35- 11.27 sec 233832448 Bytes 477.21 Mbits/sec
11.27- 15.01 sec 226230272 Bytes 483.92 Mbits/sec
15.01- 20.07 sec 305397760 Bytes 482.84 Mbits/sec
20.07- 23.30 sec 198524928 Bytes 491.70 Mbits/sec
23.30- 26.75 sec 210583552 Bytes 488.31 Mbits/sec
26.75- 30.20 sec 206946304 Bytes 479.88 Mbits/sec
0.00- 30.20 sec 2012200960 Bytes 533.03 Mbits/sec
iperf exit
nsh> iperf -s -B 10.0.1.2
IP: 10.0.1.2
mode=tcp-server sip=10.0.1.2:5001,dip=0.0.0.0:5001, interval=3, time=0
accept: 10.0.1.1:36692
Interval Transfer Bandwidth
0.00- 3.24 sec 238423900 Bytes 588.70 Mbits/sec
3.24- 7.78 sec 370243184 Bytes 652.41 Mbits/sec
closed by the peer: 10.0.1.1:36692
iperf exit
nsh>
```
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