Significant Packet Delay with quic-go on iOS Due to Goroutine Handling about quic-go HOT 3 CLOSED

The problem seems to be exacerbated by quic-go's heavy internal use of goroutines, interacting poorly with the Go runtime's thread scheduling on iOS.

Can you elaborate what you mean by heavy use? We only have one Go routine per connection, plus one for the send queue (https://github.com/quic-go/quic-go/blob/master/connection.go#L515).

You could try driving the send queue from the connection's Go routine, this should be a very simple change.

from quic-go.

Thank you for your response. I apologize for any confusion caused by my previous explanation. Upon further investigation, I realized that the issue isn't related to the heavy use of goroutines within quic-go.

To clarify, the problem appears to be with the use of even a single goroutine causing significant packet delay on iOS. Here are the details of my findings:

Testing with a Regular UDP Connection:

I set up a basic UDP connection and sent 1000-byte packets every 20 milliseconds.
When running this setup without using any goroutines, the network traffic is handled correctly with no significant delays.
However, when I wrapped the UDP connection inside a single goroutine, I observed significant packet delays.
Implications for quic-go:

Given that quic-go uses a single goroutine per connection plus one for the send queue, this behavior likely affects quic-go as well, since it involves goroutine handling.

Build Environment:

I used the following build command for iOS:

GOOS=ios GOARCH=arm64 CGO_ENABLED=1 CC=$(go env GOROOT)/misc/ios/clangwrap.sh go build -ldflags -w -v -tags ios -o "IOS.a" -buildmode=c-archive

It seems the interaction between the Go runtime's thread scheduling and goroutines on iOS is the root cause of the delay, as extensively discussed in this Go issue.

I appreciate your suggestion to drive the send queue from the connection's goroutine and will look into implementing this change to see if it mitigates the issue.

Thank you for your attention and assistance with this matter.

from quic-go.

If this is actually due to golang/go#65889, I fear there's not a lot we can do here. It seems like the only way to resolve the issue would be to avoid using Go routines altogether.

from quic-go.