ShardedInt provides an int type expvar.Var that supports more efficient
writes at high frequencies (one order of magnigude on an M1 Max, much
more on NUMA systems).
There are two implementations of ShardValue, one that abuses sync.Pool
that will work on current public Go versions, and one that takes a
dependency on a runtime.TailscaleP function exposed in Tailscale's Go
fork. The sync.Pool variant has about 10x the throughput of a single
atomic integer on an M1 Max, and the runtime.TailscaleP variant is about
10x faster than the sync.Pool variant.
Neither variant have perfect distribution, or perfectly always avoid
cross-CPU sharing, as there is no locking or affinity to ensure that the
time of yield is on the same core as the time of core biasing, but in
the average case the distributions are enough to provide substantially
better performance.
See golang/go#18802 for a related upstream proposal.
Updates tailscale/go#109
Updates tailscale/corp#25450
Signed-off-by: James Tucker <james@tailscale.com>
For https://github.com/tailscale/go/pull/108 so we can depend on it in
other repos. (This repo can't yet use it; we permit building
tailscale/tailscale with the latest stock Go release) But that will be
in Go 1.24. We're just impatient elsewhere and would like it in the
control plane code earlier.
Updates tailscale/corp#25406
Change-Id: I53ff367318365c465cbd02cea387c8ff1eb49fab
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Update go.toolchain.rev for https://github.com/tailscale/go/pull/104 and
add a test that, when using the tailscale_go build tag, we use the
right Go toolchain.
We'll crank up the strictness in later commits.
Updates #13527
Change-Id: Ifb09a844858be2beb144a420e4e9dbdc5c03ae3a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Updates tailscale/tailscale#13452
Bump the Go toolchain to the latest to pick up changes required to not crash on Android 9/10.
Signed-off-by: Andrea Gottardo <andrea@gottardo.me>
This removes the unsafe/linkname and only uses the standard library.
It's a bit slower, for now, but https://go.dev/cl/518336 should get us
back.
On darwin/arm64, without https://go.dev/cl/518336
pkg: tailscale.com/tstime/mono
│ before │ after │
│ sec/op │ sec/op vs base │
MonoNow-8 16.20n ± 0% 19.75n ± 0% +21.92% (p=0.000 n=10)
TimeNow-8 39.46n ± 0% 39.40n ± 0% -0.16% (p=0.002 n=10)
geomean 25.28n 27.89n +10.33%
And with it,
MonoNow-8 16.34n ± 1% 16.93n ± 0% +3.67% (p=0.001 n=10)
TimeNow-8 39.55n ± 15% 38.46n ± 1% -2.76% (p=0.000 n=10)
geomean 25.42n 25.52n +0.41%
Updates #8839
Updates tailscale/go#70
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
We can use the TCP_CONNECTION_INFO getsockopt() on Darwin to get
OS-collected tx/rx bytes for TCP sockets. Since this API is not available
for UDP sockets (or on Linux/Android), we can't rely on it for actual
stats gathering.
However, we can use it to validate the stats that we collect ourselves
using read/write hooks, so that we can be more confident in them. We
do need additional hooks from the Go standard library (added in
tailscale/go#59) to be able to collect them.
Updates tailscale/corp#9230
Updates #3363
Signed-off-by: Mihai Parparita <mihai@tailscale.com>
Uses the hooks added by tailscale/go#45 to instrument the reads and
writes on the major code paths that do network I/O in the client. The
convention is to use "<package>.<type>:<label>" as the annotation for
the responsible code path.
Enabled on iOS, macOS and Android only, since mobile platforms are the
ones we're most interested in, and we are less sensitive to any
throughput degradation due to the per-I/O callback overhead (macOS is
also enabled for ease of testing during development).
For now just exposed as counters on a /v0/sockstats PeerAPI endpoint.
We also keep track of the current interface so that we can break out
the stats by interface.
Updates tailscale/corp#9230
Updates #3363
Signed-off-by: Mihai Parparita <mihai@tailscale.com>
For tailscale/go#55 experimentation in another repo primarily,
but this is our source of truth, so we bump here.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Also removes the toolchain builds from flake.nix. For now the flake
build uses upstream Go 1.20, a followup change will switch it back to
our custom toolchain.
Updates tailscale/corp#9005
Signed-off-by: David Anderson <danderson@tailscale.com>
Switch to Go 1.19rc2 in prep for the Go 1.19 GA release on Tuesday.
(We won't be using any Go 1.19 features until then.)
Updates #5210
Change-Id: I94fa0ae8f5645fb7579429668f3970c18d1796d8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
