tailscale/wgengine/netstack/netstack_tcpbuf_ios.go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause

//go:build ios

package netstack

import (
	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
)

const (
	// tcp{RX,TX}Buf{Min,Def,Max}Size mirror gVisor defaults. We leave these
	// unchanged on iOS for now as to not increase pressure towards the
	// NetworkExtension memory limit.
	// TODO(jwhited): test memory/throughput impact of collapsing to values in _default.go
	tcpRXBufMinSize = tcp.MinBufferSize
	tcpRXBufDefSize = tcp.DefaultSendBufferSize
	tcpRXBufMaxSize = tcp.MaxBufferSize

	tcpTXBufMinSize = tcp.MinBufferSize
	tcpTXBufDefSize = tcp.DefaultReceiveBufferSize
	tcpTXBufMaxSize = tcp.MaxBufferSize
)
wgengine/netstack: increase gVisor's TCP send and receive buffer sizes (#12994) This commit increases gVisor's TCP max send (4->6MiB) and receive (4->8MiB) buffer sizes on all platforms except iOS. These values are biased towards higher throughput on high bandwidth-delay product paths. The iperf3 results below demonstrate the effect of this commit between two Linux computers with i5-12400 CPUs. 100ms of RTT latency is introduced via Linux's traffic control network emulator queue discipline. The first set of results are from commit f0230ce prior to TCP buffer resizing. gVisor write direction: Test Complete. Summary Results: [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 180 MBytes 151 Mbits/sec 0 sender [ 5] 0.00-10.10 sec 179 MBytes 149 Mbits/sec receiver gVisor read direction: Test Complete. Summary Results: [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.10 sec 337 MBytes 280 Mbits/sec 20 sender [ 5] 0.00-10.00 sec 323 MBytes 271 Mbits/sec receiver The second set of results are from this commit with increased TCP buffer sizes. gVisor write direction: [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 297 MBytes 249 Mbits/sec 0 sender [ 5] 0.00-10.10 sec 297 MBytes 247 Mbits/sec receiver gVisor read direction: [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.10 sec 501 MBytes 416 Mbits/sec 17 sender [ 5] 0.00-10.00 sec 485 MBytes 407 Mbits/sec receiver Updates #9707 Updates tailscale/corp#22119 Signed-off-by: Jordan Whited <jordan@tailscale.com> 4 months ago			`// Copyright (c) Tailscale Inc & AUTHORS`
			`// SPDX-License-Identifier: BSD-3-Clause`

			`//go:build ios`

			`package netstack`

			`import (`
			`"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"`
			`)`

			`const (`
			`// tcp{RX,TX}Buf{Min,Def,Max}Size mirror gVisor defaults. We leave these`
			`// unchanged on iOS for now as to not increase pressure towards the`
			`// NetworkExtension memory limit.`
			`// TODO(jwhited): test memory/throughput impact of collapsing to values in _default.go`
			`tcpRXBufMinSize = tcp.MinBufferSize`
			`tcpRXBufDefSize = tcp.DefaultSendBufferSize`
			`tcpRXBufMaxSize = tcp.MaxBufferSize`

			`tcpTXBufMinSize = tcp.MinBufferSize`
			`tcpTXBufDefSize = tcp.DefaultReceiveBufferSize`
			`tcpTXBufMaxSize = tcp.MaxBufferSize`
			`)`