[PATCH v2 1/3] wifi: iwlwifi: pcie: optimize MSI-X interrupt affinity
From: Adrián García Casado <hidden>
Date: 2026-03-15 17:25:17
Also in:
imx, linux-block, linux-mmc, linux-wireless, lkml, rust-for-linux
Subsystem:
intel wireless wifi link (iwlwifi), the rest · Maintainers:
Miri Korenblit, Linus Torvalds
Implement a balanced RSS queue distribution by skipping CPU0 for high-rate MSI-X interrupts when multiple CPUs are online. This reduces contention with system housekeeping tasks on the boot core and improves overall throughput. Signed-off-by: Adrian Garcia Cicuelo <redacted> --- drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c
index 4560d92d7..87149f29e 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c@@ -1683,7 +1683,17 @@ static void iwl_pcie_irq_set_affinity(struct iwl_trans *trans, * Get the cpu prior to the place to search * (i.e. return will be > i - 1). */ + /* + * Balanced distribution: skip CPU0 for high-rate RSS queues + * to avoid contention with system housekeeping. + */ cpu = cpumask_next(i - offset, cpu_online_mask); + if (cpu >= nr_cpu_ids) + cpu = cpumask_first(cpu_online_mask); + + if (cpu == 0 && num_online_cpus() > 1) + cpu = cpumask_next(0, cpu_online_mask); + cpumask_set_cpu(cpu, &trans_pcie->affinity_mask[i]); ret = irq_set_affinity_hint(trans_pcie->msix_entries[i].vector, &trans_pcie->affinity_mask[i]);
--
2.47.3