# Regression

To run a regression of all tests in a testlist, the regression folder will be created in the `work` folder using a combination of regression and running date/time.

The test with seed combination folder will be created in the `regression_` folder.

The options in each test command in the testlist will be ignored:

- `-wave`
- `-seed`

These options can be passed within the command of the regression.

Note that if there is a `-repeat` option in a single test command, `-seed` will be ignored, and a random seed will be used for the `-repeat` times.

Example:

VCS 3-step command

```terminal
python3 run -s_regress3=test/xxx/testlist_xxx -reg_num=8 -wave=fsdb -seed=100
```

VCS 2-step command

```terminal
python3 run -s_regress2=test/xxx/testlist_xxx -reg_num=8 -wave=fsdb -seed=100
```

**Note:** If all regression is run with waveform open, the size of the result folder will be large, which may consume too much disk space.

## Display in Terminal

All the information will be displayed with *COLOR*.

The information includes:

- The main program process PID
- The number of parallel running processes
- Total number of running cases
- Total CPU count of the current server
- Regression location in the `run` folder
- Running test details:
  - Name
  - PID
  - Starting date/time
- Finished test details:
  - Name
  - Finishing date/time
  - Duration
- Successfully finished tests (tests that may get stuck will not show)
- Test rough result: `PASSED`/`FAILED`
- Test result report file location

## -reg_num

Specifies the number of parallel regressions. Default is 5.

**Caution:** Do not set the number too high to avoid overloading the server.

Parallel running uses multiple processes on a single server. A higher number will result in faster regression time but higher system resource consumption. Please provide a reasonable number and ensure it does not disturb other engineers work.

This can be used in combination with `-lsf`/`-slurm`.

## -suite

Runs regression with the provided suite in the testlist.

## -rm_pass

In regression, this option removes passed test folders to save disk space, but the passed test logs will be retained to replace the removed folders.

## -rerun

After regression, if this option is specified, the failed tests will be collected and maintained in `reg_result_fail`. All failed tests will be rerun in the same folder within the regression folder with waveform open (currently as `fsdb`).

This makes debugging easier and faster.

## rerun_for Options

Regardless of whether `-rerun` is passed or not, this option reruns the failed tests with waveform open for the specified regression folder.

Example:

```terminal
-s_rerun2_for=regression_2028_03_21_15_37_11
```

Please check the detailed options in tools related descriptions.

## -report

This option is only valid during regression and supports both VCS-2step and VCS-3step flows.

It uses the result check tool to analyze all logs in detail and generates an HTML report (`report.html`) in the regression folder. This report can be opened and reviewed in a web browser such as Firefox.

The report is simple yet informative, displaying the following details:

- Summary of case numbers, including pass and fail counts
- Result status
- Log links (clickable if accessed on a Linux server)
- Case name
- Seed
- Simulation time
- Finish time
- Full log path
- First error encountered

When `-slurm/-lsf` is enabled, the result check tool will be submitted to the job scheduler for processing.

If this option is disabled, a basic report will still be generated during the regression process. This includes:

- Basic analysis based on the PASS/FAIL status of tests
- `reg_result` and `reg_result_fail` files created in the regression folder

If the option is disabled during regression but later required, users can navigate to the regression folder and execute the report script to generate `report.html` without rerunning the regression.

### -step2

Do the report collection in regression folder running with VCS-2step. default is VCS-3step

### -clean

In general usage, the user does not need to worry about py files used or generated by python pytest.

If the user wants to clean all the `test_xxx.py` files manually, this option is used for it.

Please refer to the Guideline_for_creating_and_managing_files.pdf for:

- error check/ignore
- warning check/ignore

This is very important for QA for verification.