What is the expected drop in throughput when using istio?

Hello, we’re currently testing the throughput of our system and we’ve found istio to affect it significantly… On a single pod, we hit 4000-5000 requests per second (rps) without istio… When enabling istio, we can only hit up to around 1600 rps (60% drop)… both test cases seems to use 4 CPU. We’ll be investigating the issue for the next few days and also try different things like disabling telemetry…
But is there really a 60% expected drop in throughput when using istio? Thanks!

Under load, it looks like istio-proxy consumes twice the CPU of our actual (test) service.

$ kubectl top pods -A --containers

test-service                      1123m        237Mi
grpc-gateway                      633m         16Mi
istio-proxy                       2213m        82Mi

which tool you stress istio?

we use locust for testing