rptest: bump multiplier to 2.0 for test_max_partitions()

[andrewhsu]

Bump latency multiplier (fudge factor) for test_max_partitions() from 1.5 to 2.0 and log warning if latency is above expected max latency, i.e. fudge factor 1.0.

This is a workaround for addressing issue #15459

example run:

ducktape \ 
 --debug \ 
 --globals=/home/ubuntu/redpanda/tests/globals.json \ 
 --cluster=ducktape.cluster.json.JsonCluster \ 
 --cluster-file=/home/ubuntu/redpanda/tests/cluster.json \  
 --test-runner-timeout=3600000 \
 tests/rptest/redpanda_cloud_tests/omb_validation_test.py::OMBValidationTest.test_max_partitions

output:

[INFO  - 2024-01-18 20:53:10,924 - omb_validation_test - test_max_partitions - lineno:390]: latency_metrics: {'aggregatedEndToEndLatency50pct': 26.589, 'aggregatedEndToEndLatency75pct': 32.568, 'aggregatedEndToEndLatency99pct': 88.523, 'aggregatedEndToEndLatency999pct': 144.91}
[WARNING - 2024-01-18 20:53:10,924 - omb_validation_test - _warn_metrics - lineno:312]: ['Metric aggregatedEndToEndLatency50pct, value 26.589, Expected to be <= 20.0, check failed.', 'Metric aggregatedEndToEndLatency75pct, value 32.568, Expected to be <= 25.0, check failed.', 'Metric aggregatedEndToEndLatency99pct, value 88.523, Expected to be <= 50.0, check failed.', 'Metric aggregatedEndToEndLatency999pct, value 144.91, Expected to be <= 100.0, check failed.']
...

test_id:    rptest.redpanda_cloud_tests.omb_validation_test.OMBValidationTest.test_max_partitions
status:     PASS
run time:   12 minutes 49.200 seconds
-----------------------------------------------------------------------------------------------------------------
====================================================================================
SESSION REPORT (ALL TESTS)
ducktape version: 0.8.18
session_id:       2024-01-18--009
run time:         12 minutes 49.219 seconds
tests run:        1
passed:           1
flaky:            0
failed:           0
ignored:          0
opassed:          0
ofailed:          0
====================================================================================

Backports Required

• none - not a bug fix
• none - this is a backport
• none - issue does not exist in previous branches
• none - papercut/not impactful enough to backport
• v23.3.x
• v23.2.x
• v23.1.x

Release Notes

• none

[andrewhsu]

ready for review

[andrewhsu]

converting to draft to update based on feedback from today's sync mtg

[andrewhsu]

PR ready for review. example output in the description

[vbotbuildovich]

new failures in https://buildkite.com/redpanda/redpanda/builds/43908#018d1ea6-0a39-4ac0-9cc5-e86795c920dd:

"rptest.tests.leadership_transfer_test.MultiTopicAutomaticLeadershipBalancingTest.test_topic_aware_rebalance"

new failures in https://buildkite.com/redpanda/redpanda/builds/43908#018d1ea6-0a30-40f6-8471-6b14ecaa53c5:

"rptest.tests.topic_creation_test.TopicRecreateTest.test_topic_recreation_while_producing.workload=IDEMPOTENT.cleanup_policy=compact"

new failures in https://buildkite.com/redpanda/redpanda/builds/43908#018d1eb8-088b-4b7d-a664-898bf883da6c:

"rptest.tests.partition_movement_test.SIPartitionMovementTest.test_cross_shard.num_to_upgrade=2.cloud_storage_type=CloudStorageType.S3"

new failures in https://buildkite.com/redpanda/redpanda/builds/44100#018d322b-c33a-486b-80a3-20aa84ae8352:

"rptest.tests.retention_policy_test.ShadowIndexingCloudRetentionTest.test_cloud_time_based_retention.cloud_storage_type=CloudStorageType.ABS"

[piyushredpanda]

The failures are all known, so I can force-merge this once we fix the conflicts, @andrewhsu

[andrewhsu]

rebased with the tip of dev. simple conflict resolved in commit 7875f35 with no functionality change.

[vbotbuildovich]

ducktape was retried in https://buildkite.com/redpanda/redpanda/builds/44100#018d3253-8c16-42a5-a694-becb78587763