# ProIO: An Event-Based I/O Stream Format for Protobuf Messages

## TL;DR

ProIO is a flexible, language-neutral event-based data format using protobuf, designed for high-energy physics data streaming, with performance benchmarks comparing it to ROOT I/O.

## Contribution

It introduces ProIO, a novel event-oriented streaming format leveraging protobuf, and evaluates its performance and size efficiency against ROOT I/O.

## Key findings

- ProIO achieves comparable or better I/O performance than ROOT I/O.
- ProIO's size-on-disk varies with compression and encoding settings.
- ProIO demonstrates high language neutrality and flexibility.

## Abstract

ProIO is a new event-oriented streaming data format which utilizes Google's Protocol Buffers (protobuf) to be flexible and highly language-neutral. The ProIO concept is described here along with its software implementations. The performance of the ProIO concept for a dataset with Monte-Carlo event records used in high-energy physics was benchmarked and compared/contrasted with ROOT I/O. Various combinations of general-purpose compression and variable-length integer encoding available in protobuf were used to investigate the relationship between I/O performance and size-on-disk in a few key scenarios.