# Objective
- Have an easy way to compare spans between executions
## Solution
- Add a tool to compare spans from chrome traces
```bash
> cargo run --release -p spancmp -- --help
Compiling spancmp v0.1.0
Finished release [optimized] target(s) in 1.10s
Running `target/release/spancmp --help`
spancmp
USAGE:
spancmp [OPTIONS] <TRACE> [SECOND_TRACE]
ARGS:
<TRACE>
<SECOND_TRACE>
OPTIONS:
-h, --help Print help information
-p, --pattern <PATTERN> Filter spans by name matching the pattern
-t, --threshold <THRESHOLD> Filter spans that have an average shorther than the threshold
[default: 0]
```
for each span, it will display the count, minimum duration, average duration and max duration. It can be filtered by a pattern on the span name or by a minimum average duration.
just displaying a trace
![Screenshot 2022-04-28 at 21 56 21](https://user-images.githubusercontent.com/8672791/165835310-f465c6f2-9e6b-4808-803e-884b06e49292.png)
comparing two traces
![Screenshot 2022-04-28 at 21 56 55](https://user-images.githubusercontent.com/8672791/165835353-097d266b-a70c-41b8-a8c1-27804011dc97.png)
Co-authored-by: Robert Swain <robert.swain@gmail.com>