From 24b2e73f9700e0682575feb34556b756e59d4548 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Wed, 1 Apr 2026 06:03:56 -0700 Subject: workqueue: add test_workqueue benchmark module Add a kernel module that benchmarks queue_work() throughput on an unbound workqueue to measure pool->lock contention under different affinity scope configurations (cache vs cache_shard). The module spawns N kthreads (default: num_online_cpus()), each bound to a different CPU. All threads start simultaneously and queue work items, measuring the latency of each queue_work() call. Results are reported as p50/p90/p95 latencies for each affinity scope. The affinity scope is switched between runs via the workqueue's sysfs affinity_scope attribute (WQ_SYSFS), avoiding the need for any new exported symbols. The module runs as __init-only, returning -EAGAIN to auto-unload, and can be re-run via insmod. Example of the output: running 50 threads, 50000 items/thread cpu 6806017 items/sec p50=2574 p90=5068 p95=5818 ns smt 6821040 items/sec p50=2624 p90=5168 p95=5949 ns cache_shard 1633653 items/sec p50=5337 p90=9694 p95=11207 ns cache 286069 items/sec p50=72509 p90=82304 p95=85009 ns numa 319403 items/sec p50=63745 p90=73480 p95=76505 ns system 308461 items/sec p50=66561 p90=75714 p95=78048 ns Signed-off-by: Breno Leitao Signed-off-by: Tejun Heo --- lib/Kconfig.debug | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'lib/Kconfig.debug') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4e2dfbbd3d78..cba976b29f32 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2654,6 +2654,16 @@ config TEST_VMALLOC If unsure, say N. +config TEST_WORKQUEUE + tristate "Test module for stress/performance analysis of workqueue" + default n + help + This builds the "test_workqueue" module for benchmarking + workqueue throughput under contention. Useful for evaluating + affinity scope changes (e.g., cache_shard vs cache). + + If unsure, say N. + config TEST_BPF tristate "Test BPF filter functionality" depends on m && NET -- cgit v1.2.3