tailscale

Commit Graph

Author	SHA1	Message	Date
Josh Bleecher Snyder	99705aa6b7	net/tstun: split TUN events channel into up/down and MTU We had a long-standing bug in which our TUN events channel was being received from simultaneously in two places. The first is wireguard-go. At wgengine/userspace.go:366, we pass e.tundev to wireguard-go, which starts a goroutine (RoutineTUNEventReader) that receives from that channel and uses events to adjust the MTU and bring the device up/down. At wgengine/userspace.go:374, we launch a goroutine that receives from e.tundev, logs MTU changes, and triggers state updates when up/down changes occur. Events were getting delivered haphazardly between the two of them. We don't really want wireguard-go to receive the up/down events; we control the state of the device explicitly by calling device.Up. And the userspace.go loop MTU logging duplicates logging that wireguard-go does when it received MTU updates. So this change splits the single TUN events channel into up/down and other (aka MTU), and sends them to the parties that ought to receive them. I'm actually a bit surprised that this hasn't caused more visible trouble. If a down event went to wireguard-go but the subsequent up event went to userspace.go, we could end up with the wireguard-go device disappearing. I believe that this may also (somewhat accidentally) be a fix for #1790. Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>	3 years ago
Avery Pennarun	a92b9647c5	wgengine/bench: speed test for channels, sockets, and wireguard-go. This tries to generate traffic at a rate that will saturate the receiver, without overdoing it, even in the event of packet loss. It's unrealistically more aggressive than TCP (which will back off quickly in case of packet loss) but less silly than a blind test that just generates packets as fast as it can (which can cause all the CPU to be absorbed by the transmitter, giving an incorrect impression of how much capacity the total system has). Initial indications are that a syscall about every 10 packets (TCP bulk delivery) is roughly the same speed as sending every packet through a channel. A syscall per packet is about 5x-10x slower than that. The whole tailscale wireguard-go + magicsock + packet filter combination is about 4x slower again, which is better than I thought we'd do, but probably has room for improvement. Note that in "full" tailscale, there is also a tundev read/write for every packet, effectively doubling the syscall overhead per packet. Given these numbers, it seems like read/write syscalls are only 25-40% of the total CPU time used in tailscale proper, so we do have significant non-syscall optimization work to do too. Sample output: $ GOMAXPROCS=2 go test -bench . -benchtime 5s ./cmd/tailbench goos: linux goarch: amd64 pkg: tailscale.com/cmd/tailbench cpu: Intel(R) Core(TM) i7-4785T CPU @ 2.20GHz BenchmarkTrivialNoAlloc/32-2 56340248 93.85 ns/op 340.98 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkTrivialNoAlloc/124-2 57527490 99.27 ns/op 1249.10 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkTrivialNoAlloc/1024-2 52537773 111.3 ns/op 9200.39 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkTrivial/32-2 41878063 135.6 ns/op 236.04 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkTrivial/124-2 41270439 138.4 ns/op 896.02 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkTrivial/1024-2 36337252 154.3 ns/op 6635.30 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkBlockingChannel/32-2 12171654 494.3 ns/op 64.74 MB/s 0 %lost 1791 B/op 0 allocs/op BenchmarkBlockingChannel/124-2 12149956 507.8 ns/op 244.17 MB/s 0 %lost 1792 B/op 1 allocs/op BenchmarkBlockingChannel/1024-2 11034754 528.8 ns/op 1936.42 MB/s 0 %lost 1792 B/op 1 allocs/op BenchmarkNonlockingChannel/32-2 8960622 2195 ns/op 14.58 MB/s 8.825 %lost 1792 B/op 1 allocs/op BenchmarkNonlockingChannel/124-2 3014614 2224 ns/op 55.75 MB/s 11.18 %lost 1792 B/op 1 allocs/op BenchmarkNonlockingChannel/1024-2 3234915 1688 ns/op 606.53 MB/s 3.765 %lost 1792 B/op 1 allocs/op BenchmarkDoubleChannel/32-2 8457559 764.1 ns/op 41.88 MB/s 5.945 %lost 1792 B/op 1 allocs/op BenchmarkDoubleChannel/124-2 5497726 1030 ns/op 120.38 MB/s 12.14 %lost 1792 B/op 1 allocs/op BenchmarkDoubleChannel/1024-2 7985656 1360 ns/op 752.86 MB/s 13.57 %lost 1792 B/op 1 allocs/op BenchmarkUDP/32-2 1652134 3695 ns/op 8.66 MB/s 0 %lost 176 B/op 3 allocs/op BenchmarkUDP/124-2 1621024 3765 ns/op 32.94 MB/s 0 %lost 176 B/op 3 allocs/op BenchmarkUDP/1024-2 1553750 3825 ns/op 267.72 MB/s 0 %lost 176 B/op 3 allocs/op BenchmarkTCP/32-2 11056336 503.2 ns/op 63.60 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkTCP/124-2 11074869 533.7 ns/op 232.32 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkTCP/1024-2 8934968 671.4 ns/op 1525.20 MB/s 0 %lost 0 B/op 0 allocs/op BenchmarkWireGuardTest/32-2 1403702 4547 ns/op 7.04 MB/s 14.37 %lost 467 B/op 3 allocs/op BenchmarkWireGuardTest/124-2 780645 7927 ns/op 15.64 MB/s 1.537 %lost 420 B/op 3 allocs/op BenchmarkWireGuardTest/1024-2 512671 11791 ns/op 86.85 MB/s 0.5206 %lost 411 B/op 3 allocs/op PASS ok tailscale.com/wgengine/bench 195.724s Updates #414. Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>	3 years ago
Brad Fitzpatrick	939861773d	net/tstun: accept peerapi connections through the filter Fixes tailscale/corp#1545 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	3 years ago
Brad Fitzpatrick	41e4e02e57	net/{packet,tstun}: send peerapi port in TSMP pongs For discovery when an explicit hostname/IP is known. We'll still also send it via control for finding peers by a list. Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>	3 years ago
David Anderson	016de16b2e	net/tstun: rename TUN to Wrapper. The tstun packagen contains both constructors for generic tun Devices, and a wrapper that provides additional functionality. Signed-off-by: David Anderson <danderson@tailscale.com>	3 years ago
David Anderson	588b70f468	net/tstun: merge in wgengine/tstun. Signed-off-by: David Anderson <danderson@tailscale.com>	3 years ago

1 2

56 Commits (d2fd101eb451858e2b81905d95763b8da224bbd8)