Question about Benchmarking and Performance in rinf

[ganeshrvel]

Hi rinf team,

I stumbled on this project while looking for a way to use Rust in Flutter combination. Thanks for this amazing package. Great going.

I have a few questions though:

a. Do you have any existing benchmarks for rinf?

b. If I have hundreds of thousands of struct data (mostly metadata info) coming as a list from Rust to Dart, will there be a memory copy overhead?

1. If yes, does rinf introduce overhead in copying the vector to and from Rust?
2. Are there any benchmarks conducted on this aspect?
3. How much memory overhead can be expected in such scenarios?

c. Since Dart uses message ports to communicate, is there any noticeable delay or overhead observed?

1. When sending a communication from Flutter to Rust, a message-port signal request is sent to Rust from Flutter. Does this cause a very brief UI freeze?
2. If yes, to avoid UI freezing for a few milliseconds, do we need to start the call to Rust using an isolate or is it all done under the hood?
3. If yes, will starting an isolate add noticeable delay in communication due to the overhead of cold starting an isolate in Dart language?

Thanks

[temeddix]

Hello :)

a. Unfortunately, benchmarks are not present. You can consider the Protobuf serialization performance as a potential UI blocking factor. It shouldn't block unless the message is very large(More than hundreds of megabytes).

b.

1. A RustSignal and DartSignal both consist of a pair of Protobuf message binary and raw binary. You need to consider Protobuf serialization as a separate overhead factor. While copying raw binary from Dart to Rust, memory copy is unavoidable because Rust has an ownership system that cannot coexist with garbage-collected Dart objects.

Operation and Data	PB Serialization	Mem Copy	Details
Dart >> Rust (Message)	O	O	Dart mallocs on heap, Rust deserializes from its slice
Dart >> Rust (Raw Binary)	X	O	Dart mallocs on heap, Rust copies it
Rust >> Dart (Message)	O	X	Rust gives ownership, Dart deserializes from it
Rust >> Dart (Raw Binary)	X	X	Rust gives ownership

2. Unfortunately, no.
3. Memory overhead can be expected when you include raw binary in a signal from Dart to Rust. The time spent on this is for writing the data in the heap and then copying it again as Vec<u8>.

c.

1. If the Protobuf serialization cost is significant (which is unlikely), then yes, it is possible to experience a brief UI freeze.
2. Other than message serialization, there's no blocking factor; therefore, a Dart isolate is not needed. Dart and Rust (tokio) always run on different sets of threads, and Rust tasks never block the Dart runtime or UI.
3. So this answer might not be relevant.