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Tue, 17 Mar 2026 12:32:57 -0700 (PDT) Received: from debian.lan ([171.22.84.130]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-486f420d7b5sm21977775e9.2.2026.03.17.12.32.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Mar 2026 12:32:56 -0700 (PDT) From: =?UTF-8?q?Adri=C3=A1n=20Garc=C3=ADa=20Casado?= To: Miri Korenblit Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, Miguel Ojeda , =?UTF-8?q?Adri=C3=A1n=20Garc=C3=ADa=20Casado?= Subject: [PATCH v4] wifi: iwlwifi: pcie: optimize MSI-X interrupt affinity Date: Tue, 17 Mar 2026 20:32:52 +0100 Message-ID: <20260317193252.13763-1-adriangarciacasado42@gmail.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Balanced distribution: skip CPU0 for high-rate RSS queues to avoid contenti= on with system housekeeping. Use a stateful last_cpu approach to ensure uni= que core assignment when skipping CPU0. This avoids mapping multiple queues= to the same core. Signed-off-by: Adri=C3=A1n Garc=C3=ADa Casado --- .../intel/iwlwifi/pcie/gen1_2/trans.c | 20 ++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c b/drive= rs/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c index 4560d92d7..7077ec015 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/gen1_2/trans.c @@ -1672,18 +1672,28 @@ static void iwl_pcie_irq_set_affinity(struct iwl_tr= ans *trans, struct iwl_trans_info *info) { #if defined(CONFIG_SMP) - int iter_rx_q, i, ret, cpu, offset; + int iter_rx_q, i, ret, cpu, offset, last_cpu; struct iwl_trans_pcie *trans_pcie =3D IWL_TRANS_GET_PCIE_TRANS(trans); =20 i =3D trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_FIRST_RSS ? 0 : 1; iter_rx_q =3D info->num_rxqs - 1 + i; - offset =3D 1 + i; + last_cpu =3D -1; for (; i < iter_rx_q ; i++) { /* - * 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 =3D cpumask_next(i - offset, cpu_online_mask); + cpu =3D cpumask_next(last_cpu, cpu_online_mask); + if (cpu >=3D nr_cpu_ids) + cpu =3D cpumask_first(cpu_online_mask); + + if (cpu =3D=3D 0 && num_online_cpus() > 1) { + cpu =3D cpumask_next(0, cpu_online_mask); + if (cpu >=3D nr_cpu_ids) + cpu =3D cpumask_first(cpu_online_mask); + } + last_cpu =3D cpu; + cpumask_set_cpu(cpu, &trans_pcie->affinity_mask[i]); ret =3D irq_set_affinity_hint(trans_pcie->msix_entries[i].vector, &trans_pcie->affinity_mask[i]); --=20 2.47.3