Create configuration for fdbased processor goroutines.

This configuration doesn't do anything right now, the implementation is
in the child change.

PiperOrigin-RevId: 627194527

pkg/tcpip/link/fdbased/endpoint.go

@@ -226,6 +226,10 @@ type Options struct {
 
 	// GRO enables generic receive offload.
 	GRO bool
+
+	// ProcessorsPerChannel is the number of goroutines used to handle packets
+	// from each FD.
+	ProcessorsPerChannel int
 }
 
 // fanoutID is used for AF_PACKET based endpoints to enable PACKET_FANOUT

runsc/boot/network.go

@@ -109,6 +109,10 @@ type FDBasedLink struct {
 	// NumChannels controls how many underlying FDs are to be used to
 	// create this endpoint.
 	NumChannels int
+
+	// ProcessorsPerChannel controls how many goroutines are used to handle
+	// packets on each channel.
+	ProcessorsPerChannel int
 }
 
 // BindOpt indicates whether the sentry or runsc process is responsible for
@@ -309,16 +313,17 @@ func (n *Network) CreateLinksAndRoutes(args *CreateLinksAndRoutesArgs, _ *struct
 			log.Infof("gso max size is: %d", link.GSOMaxSize)
 
 			linkEP, err := fdbased.New(&fdbased.Options{
-				FDs:                FDs,
-				MTU:                uint32(link.MTU),
-				EthernetHeader:     mac != "",
-				Address:            mac,
-				PacketDispatchMode: dispatchMode,
-				GSOMaxSize:         link.GSOMaxSize,
-				GVisorGSOEnabled:   link.GVisorGSOEnabled,
-				TXChecksumOffload:  link.TXChecksumOffload,
-				RXChecksumOffload:  link.RXChecksumOffload,
-				GRO:                link.GVisorGRO,
+				FDs:                  FDs,
+				MTU:                  uint32(link.MTU),
+				EthernetHeader:       mac != "",
+				Address:              mac,
+				PacketDispatchMode:   dispatchMode,
+				GSOMaxSize:           link.GSOMaxSize,
+				GVisorGSOEnabled:     link.GVisorGSOEnabled,
+				TXChecksumOffload:    link.TXChecksumOffload,
+				RXChecksumOffload:    link.RXChecksumOffload,
+				GRO:                  link.GVisorGRO,
+				ProcessorsPerChannel: link.ProcessorsPerChannel,
 			})
 			if err != nil {
 				return err

runsc/config/config.go

@@ -239,6 +239,12 @@ type Config struct {
 	// scale for high throughput use cases.
 	NumNetworkChannels int `flag:"num-network-channels"`
 
+	// NetworkProcessorsPerChannel controls the number of goroutines used to
+	// handle packets on a single network channel. A higher number can help handle
+	// many simultaneous connections. If this is 0, runsc will divide GOMAXPROCS
+	// evenly among each network channel.
+	NetworkProcessorsPerChannel int `flag:"network-processors-per-channel"`
+
 	// Rootless allows the sandbox to be started with a user that is not root.
 	// Defense in depth measures are weaker in rootless mode. Specifically, the
 	// sandbox and Gofer process run as root inside a user namespace with root

runsc/config/flags.go

@@ -119,6 +119,7 @@ func RegisterFlags(flagSet *flag.FlagSet) {
 	flagSet.Bool("rx-checksum-offload", true, "enable RX checksum offload.")
 	flagSet.Var(queueingDisciplinePtr(QDiscFIFO), "qdisc", "specifies which queueing discipline to apply by default to the non loopback nics used by the sandbox.")
 	flagSet.Int("num-network-channels", 1, "number of underlying channels(FDs) to use for network link endpoints.")
+	flagSet.Int("network-processors-per-channel", 1, "number of goroutines in each channel for processng inbound packets. If 0, the link endpoint will divide GOMAXPROCS evenly among the number of channels specified by num-network-channels.")
 	flagSet.Bool("buffer-pooling", true, "DEPRECATED: this flag has no effect. Buffer pooling is always enabled.")
 	flagSet.Var(&xdpConfig, "EXPERIMENTAL-xdp", `whether and how to use XDP. Can be one of: "off" (default), "ns", "redirect:<device name>", or "tunnel:<device name>"`)
 	flagSet.Bool("EXPERIMENTAL-xdp-need-wakeup", true, "EXPERIMENTAL. Use XDP_USE_NEED_WAKEUP with XDP sockets.") // TODO(b/240191988): Figure out whether this helps and remove it as a flag.

runsc/sandbox/network.go

@@ -281,16 +281,17 @@ func createInterfacesAndRoutesFromNS(conn *urpc.Client, nsPath string, conf *con
 			})
 		} else {
 			link := boot.FDBasedLink{
-				Name:              iface.Name,
-				MTU:               iface.MTU,
-				Routes:            routes,
-				TXChecksumOffload: conf.TXChecksumOffload,
-				RXChecksumOffload: conf.RXChecksumOffload,
-				NumChannels:       conf.NumNetworkChannels,
-				QDisc:             conf.QDisc,
-				Neighbors:         neighbors,
-				LinkAddress:       linkAddress,
-				Addresses:         addresses,
+				Name:                 iface.Name,
+				MTU:                  iface.MTU,
+				Routes:               routes,
+				TXChecksumOffload:    conf.TXChecksumOffload,
+				RXChecksumOffload:    conf.RXChecksumOffload,
+				NumChannels:          conf.NumNetworkChannels,
+				ProcessorsPerChannel: conf.NetworkProcessorsPerChannel,
+				QDisc:                conf.QDisc,
+				Neighbors:            neighbors,
+				LinkAddress:          linkAddress,
+				Addresses:            addresses,
 			}
 
 			log.Debugf("Setting up network channels")