cpuio engine does not honor output-format of json or json+

[aggieNick02]

Please acknowledge the following before creating a ticket

• [X] I have read the GitHub issues section of REPORTING-BUGS.

Description of the bug: When using json/json+ output-format, a cpuio engine job will print output lines before the json/json+ output, breaking anybody that assumes the output will be standard json

Environment: Ubuntu 20.04 LTS

fio version: 3.29

Reproduction steps Run fio --name=job --ioengine=cpuio --cpuload=1 --time_based=1 --runtime=5s --output-format=json

Output will be

job (noop): ioengine=cpuio, cpuload=1, cpucycle=50000
{
  "fio version" : "fio-3.29",
<remainder of output clipped>

[vincentkfu]

This is a longstanding issue:

https://github.com/axboe/fio/issues/731 https://github.com/axboe/fio/issues/1304

Until someone steps up to fix it my suggestion is to work around it by skipping lines until the output parses successfully.

[aggieNick02]

Thanks for pointing those out. Do you have any tips or recommendations for getting commits for open issues merged? (I have one that's been sitting for a bit.)

[vincentkfu]

The main impediment is that there aren't many people reviewing patches. My only suggestion is to make your patches as easy to review as possible by, for example, including testing instructions/scripts.