[kurok]

Closes #238

The bug

Only feeder rows were sharded. num_requests, rate and rate_ramp went to every node unchanged, so:

• --master --expect-workers 3 -n 1000 ran 3,000 requests
• --rate 100 drove 300 rps

while the README said "The master splits the workload evenly across workers". A capacity or SLO gate applied three times the load it was asked for, and nothing in the output said so.

The fix

num_requests is divided with the remainder going to the low-numbered nodes, so the shards sum to exactly -n (1000 across 3 → 334/333/333, and no node does more than one request more than any other). rate and rate_ramp are divided by the node count.

connections is deliberately not sharded — it sizes that node's own pool, not a share of the cluster's work — and neither is duration, since every node runs the whole window.

The split is logged when the config goes out:

Master: splitting the load across 3 workers: -n 1,000 -> 334/333/333, --rate 100 -> 33.3333 rps each

Together with #236 this closes the loop on distributed load shape: the profile now reaches the workers, and the base rate it scales is now the node's share rather than the cluster total.

A test that asserted the bug

tests/test_pywrkr.py::test_master_worker_multiple asserted total_requests >= 20 for -n 10 across two workers, with the comment "Each worker sends at least num_requests, so merged should have >= 2x". That is the defect, written down as the expectation. It now asserts the cluster total is 10, with a note saying what it used to claim and why.

Tests

• tests/test_audit_distributed.py::TestMasterShardsLoad::test_master_shards_num_requests_and_rate_across_workers — two real sockets read their config off the wire. Asserts num_requests sums to 10, each rate is 3.0, and connections is untouched. Pre-fix: AssertionError: 20 != 10.
• tests/test_distributed.py::TestLoadSharding — six cases on the arithmetic: shards sum to the total for 2/3/4/7 workers and stay within one of each other, rates sum back to the target, connections/duration are per node, more workers than requests gives the surplus nodes 0, a single worker is returned untouched, and a duration-only run has nothing to shard.

Checks

ruff format/check clean, mypy clean, 1920 passed.

[codecov]

Codecov Report

❌ Patch coverage is 96.29630% with 1 line in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/pywrkr/distributed.py	96.29%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!