asim: don't swallow warning about unrealistic node capacity

We can address them in a separate PR.

Author: tbg

pkg/kv/kvserver/asim/tests/datadriven_simulation_test.go

@@ -314,7 +314,7 @@ func TestDataDriven(t *testing.T) {
 				var nodes = 3
 				var storesPerNode = 1
 				var storeByteCapacity int64 = 256 << 30 /* 256 GiB  */
-				var nodeCPURateCapacity int64
+				var nodeCPURateCapacity int64 = 8 * 1e9 // 8 vcpus
 				var region []string
 				var nodesPerRegion []int
 				scanIfExists(t, d, "nodes", &nodes)
@@ -334,9 +334,13 @@ func TestDataDriven(t *testing.T) {
 				var buf strings.Builder
 				if c := float64(nodeCPURateCapacity) / 1e9; c < 1 {
 					// The load is very small, which is likely an accident.
+					// TODO(mma): fix up the tests that trigger this warning.
+					// TODO(mma): print a warning whenever the measured CPU utilization
+					// on a node exceeds this capacity, as that's likely not what the test
+					// intended.
 					_, _ = fmt.Fprintf(&buf, "WARNING: node CPU capacity of ≈%.2f cores is likely accidental\n", c)
 				}
-				return ""
+				return buf.String()
 			case "load_cluster":
 				var cfg string
 				scanMustExist(t, d, "config", &cfg)

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_constraint_satisfaction1.txt

@@ -5,6 +5,7 @@ skip_under_ci
 # a(n1.n2) b(n3,n4) c(n5) d(n6-n9)
 gen_cluster nodes=9 region=(a,b,c,d) nodes_per_region=(3,2,1,3) node_cpu_rate_capacity=50000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 # specify non-voters
 # (s1-3: region a) (s4-5: region b) (s6: region c) (s7-9: region d)

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_constraint_satisfaction_old_alloc.txt

@@ -5,6 +5,7 @@ skip_under_ci
 # a(n1.n2) b(n3,n4) c(n5) d(n6-n9)
 gen_cluster nodes=9 region=(a,b,c,d) nodes_per_region=(3,2,1,3) node_cpu_rate_capacity=50000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 # specify non-voters
 # (s1-3: region a) (s4-5: region b) (s6: region c) (s7-9: region d)

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_high_cpu.txt

@@ -3,6 +3,7 @@ skip_under_ci
 
 gen_cluster nodes=10 node_cpu_rate_capacity=800000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 # Set the rebalance mode to use the mma store rebalancer and disable the lease
 # and replicate queues so that only the mma store rebalancer is moving replicas

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_high_cpu_25nodes.txt

@@ -3,6 +3,7 @@ skip_under_ci
 
 gen_cluster nodes=25 node_cpu_rate_capacity=800000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 setting split_queue_enabled=false
 ----

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_high_cpu_skewed_placement.txt

@@ -1,5 +1,6 @@
 gen_cluster nodes=7 node_cpu_rate_capacity=50000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 # The placement will be skewed, s.t. n1/s1, n2/s2 and n3/s3 will have all the
 # replicas initially and n1/s1 will have every lease. Each range is initially

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_high_cpu_unable_to_shed_leases.txt

@@ -7,6 +7,7 @@
 #     rebalancing away from the store occurs.
 gen_cluster nodes=5 node_cpu_rate_capacity=90000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 setting split_queue_enabled=false
 ----

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_high_write_uniform_cpu.txt

@@ -3,6 +3,7 @@ skip_under_ci
 
 gen_cluster nodes=10 node_cpu_rate_capacity=30000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 # Read only workload, which generates 100_000 request cpu nanos/s evenly over
 # the first half of the keyspace, which will be on all stores initially.

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_one_voter_skewed_cpu_skewed_write.txt

@@ -5,6 +5,7 @@ skip_under_ci
 
 gen_cluster nodes=2 node_cpu_rate_capacity=100000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 gen_ranges ranges=100 repl_factor=1 min_key=1 max_key=10000 placement_type=replica_placement bytes=26843545
 {s1}:1

pkg/kv/kvserver/asim/tests/testdata/non_rand/mma_skewed_cpu_skewed_write.txt

@@ -10,6 +10,7 @@ skip_under_ci
 
 gen_cluster nodes=6 node_cpu_rate_capacity=50000
 ----
+WARNING: node CPU capacity of ≈0.00 cores is likely accidental
 
 # The placement will be skewed, s.t. n1/s1, n2/s2 and n3/s3 will have all the
 # replicas initially and n1/s1 will have every lease. Each range is initially