To be scraped in the Go expvar JSON format, as a string is involved.
For a future tool to record when processes restarted exactly, and at
what version.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
If a peer is connected to multiple nodes in a region (so
multiForwarder is in use) and then a node restarts and re-sends all
its additions, this bug about whether an element is in the
multiForwarder could cause a one-time flip in the which peer node we
forward to. Note a huge deal, but not written as intended.
Thanks to @lewgun for the bug report in #2141.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This log is quite verbose, it was only to be left in for one
unstable build to help debug a user issue.
This reverts commit 1dd2552032.
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
This is useful for manual performance testing
of networks with many nodes.
I imagine it'll grow more knobs over time.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Intended to help in resolving customer issue with
DNS caching.
We currently exec `ipconfig /flushdns` from two
places:
- SetDNS(), which logs before invoking
- here in router_windows, which doesn't
We'd like to see a positive indication in logs that flushdns
is being run.
As this log is expected to be spammy, it is proposed to
leave this in just long enough to do an unstable 1.13.x build
and then revert it. They won't run an unsigned image that
I build.
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
The number of peers we have will be pretty stable across time.
Allocate roughly the right slice size.
This reduces memory usage when there are many peers.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Two optimizations.
Use values instead of pointers.
We were using pointers to make track the "peer in progress" easier.
It's not too hard to do it manually, though.
Make two passes through the data, so that we can size our
return value accurately from the beginning.
This is cheap enough compared to the allocation,
which grows linearly in the number of peers,
that it is worth doing.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
The netmaps can get really large.
Printing, processing, and uploading them is expensive.
Only print the header on an ongoing basis.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
The number of packet filters can grow very large,
so this log entry can be very large.
We can get the packet filter server-side,
so reduce verbosity here to just the number of filters present.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
The code goes to some effort to send a single JSON object
when there's only a single line and a JSON array when there
are multiple lines.
It makes the code more complex and more expensive;
when we add a second line, we have to use a second buffer
to duplicate the first one after adding a leading square brackets.
The savings come to two bytes. Instead, always send an array.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Scanning log lines is a frequent source of allocations.
Pre-allocate a re-usable buffer.
This still doesn't help when there are giant log lines.
Those will still be problematic from an iOS memory perspective.
For more on that, see https://github.com/tailscale/corp/issues/2423.
(For those who cannot follow that link, it is a discussion
of particular problematic types of log lines for
particular categories of customers. The "categories of customers"
part is the reason that it is a private issue.)
There is also a latent bug here. If we ever encounter
a log line longer than bufio.MaxScanTokenSize,
then bufio.Scan will return an error,
and we'll truncate the file and discard the rest of the log.
That's not good, but bufio.MaxScanTokenSize is really big,
so it probably doesn't matter much in practice now.
Unfortunately, it does prevent us from easily capping the potential
memory usage here, on pain of losing log entries.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Prior to Go 1.16, iOS used GOOS=darwin,
so we had to distinguish macOS from iOS during GOARCH.
We now require Go 1.16 in our go.mod, so we can simplify.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Now that we have the easier-to-parse go:build build tags,
it is straightforward to simplify them. Yay.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Mostly so the Linux one can use Linux-specific stuff in package
syscall and not use os/exec for uname for portability.
But also it helps deps a tiny bit on iOS.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
