During performance testing sidecar reports HTTP/2" 0 or HTTP/2" 503 response codes

Hello Everyone

On running traffic (5600 tps) over application with istio injection I am getting below error in sidecar container of applications ingress-gateway for http2 inbound requests

It is either response 503 or response code 0 DC
Most of the requests (~70 %) to ingress gateway @ 5600 tps are failing.

[2021-05-24T15:11:07.888Z] “GET /nnrf-disc/v1/nf-instances?target-nf-type=PCF&requester-nf-type=SMF&requester-nf-instance-fqdn=nsmf-perf-2.smf.5gc.vzimstest.com&supi=imsi-500&snssais=%5B%7B%22sd%22%3A%22dab37d%22%2C%22sst%22%3A100%7D%5D&dnn=dnn-2 HTTP/2” 503 - “-” “-” 0 148 32256 32255 “-” “Go-http-client/2.0” “ae6bd34b-52ef-486b-968c-e49e4cc6ee7f” “ocnrf-ingressgateway.demo1” “127.0.0.1:8081” inbound|80|http2-tcp|ocnrf-ingressgateway.demo1.svc.prowl 127.0.0.1:45586 10.233.118.108:8081 10.233.125.149:50598 - default

[2021-05-24T15:11:07.597Z] “GET /nnrf-disc/v1/nf-instances?target-nf-type=PCF&requester-nf-type=SMF&requester-nf-instance-fqdn=nsmf-perf-14.smf.5gc.vzimstest.com&supi=imsi-500&snssais=%5B%7B%22sd%22%3A%22dab37d%22%2C%22sst%22%3A100%7D%5D&dnn=dnn-2 HTTP/2” 0 DC “-” “-” 0 0 32546 - “-” “Go-http-client/2.0” “2847a65e-de1b-4a80-a274-ab022cde4305” “ocnrf-ingressgateway.demo1” “127.0.0.1:8081” inbound|80|http2-tcp|ocnrf-ingressgateway.demo1.svc.prowl 127.0.0.1:45550 10.233.118.108:8081 10.233.109.162:53646 - default