[benchmark] Add "dashboard" category to scenario_config.py (#33907)

This PR covers C++ only. Other language owners: feel free to ping me if
this would be useful for you.

This allows scenario_config to produce a small superset of tests
required to generate the performance dashboard
https://grafana-dot-grpc-testing.appspot.com/. This only adds a category
to some existing scenarios, and to my knowledge, should not affect any
current automation that uses scenario_config.

I plan to use this category to run gRPC-core experiments and produce
equivalent dashboards. It seems worth landing this independently of
those job configurations, but I'm flexible.

---------

Co-authored-by: drfloob <drfloob@users.noreply.github.com>

tools/run_tests/performance/scenario_config.py

@@ -25,6 +25,9 @@ SCALABLE = "scalable"
 INPROC = "inproc"
 SWEEP = "sweep"
 PSM = "psm"
+# A small superset of the benchmarks required to produce
+# https://grafana-dot-grpc-testing.appspot.com/
+DASHBOARD = "dashboard"
 DEFAULT_CATEGORIES = (SCALABLE, SMOKETEST)
 
 SECURE_SECARGS = {
@@ -527,7 +530,7 @@ class CXXLanguage(Language):
                 minimal_stack=not secure,
                 categories=smoketest_categories
                 + inproc_categories
-                + [SCALABLE],
+                + [SCALABLE, DASHBOARD],
             )
 
             for rpc_type in [
@@ -536,6 +539,9 @@ class CXXLanguage(Language):
                 "streaming_from_client",
                 "streaming_from_server",
             ]:
+                maybe_dashboard = (
+                    [DASHBOARD] if rpc_type in ("unary", "streaming") else []
+                )
                 for synchronicity in ["sync", "async"]:
                     yield _ping_pong_scenario(
                         "cpp_protobuf_%s_%s_ping_pong_%s"
@@ -546,6 +552,7 @@ class CXXLanguage(Language):
                         async_server_threads=1,
                         minimal_stack=not secure,
                         secure=secure,
+                        categories=list(DEFAULT_CATEGORIES) + maybe_dashboard,
                     )
 
                     for size in geometric_progression(
@@ -576,6 +583,11 @@ class CXXLanguage(Language):
                         # see b/198275705
                         maybe_scalable = [SWEEP]
 
+                    maybe_dashboard = (
+                        [DASHBOARD]
+                        if rpc_type in ("unary", "streaming")
+                        else []
+                    )
                     yield _ping_pong_scenario(
                         "cpp_protobuf_%s_%s_qps_unconstrained_%s"
                         % (synchronicity, rpc_type, secstr),
@@ -587,7 +599,9 @@ class CXXLanguage(Language):
                         minimal_stack=not secure,
                         server_threads_per_cq=2,
                         client_threads_per_cq=2,
-                        categories=inproc_categories + maybe_scalable,
+                        categories=inproc_categories
+                        + maybe_scalable
+                        + maybe_dashboard,
                     )
 
                     # TODO(vjpai): Re-enable this test. It has a lot of timeouts

tools/run_tests/performance/scenario_config_exporter.py

@@ -188,7 +188,15 @@ def main() -> None:
     argp.add_argument(
         "--category",
         default="all",
-        choices=["all", "inproc", "scalable", "smoketest", "sweep", "psm"],
+        choices=[
+            "all",
+            "inproc",
+            "scalable",
+            "smoketest",
+            "sweep",
+            "psm",
+            "dashboard",
+        ],
         help="Select scenarios for a category of tests.",
     )
     argp.add_argument(