By default each Cloud Run container instance can receive up to 80 requests at the same time; you can increase this to a maximum of 1000. Although you should use the default value, if needed you can lower the maximum concurrency. For example, if your code cannot process parallel requests, set concurrency to 1 . 

https://developerpitstop.com/how-many-concurrent-requests-can-a-web-server-handle/