Which metrics stands for parallel requests from Envoy to cluster

[YvesZHI]

I want to monitor how many parallel requests are generated by Envoy to a cluster per second.

I've read the official doc about metrics of cluster but I can't find any relative metrics about parallel requests.

I know there is a upstream_rq_active, but I don't think this is what I need. I need to monitor the number of parallel requests per second, I don't think parallel requests and active requests are the same thing.

Does Envoy support such a kind of metrics?