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Wed, 15 Apr 2026 17:48:48 -0700 (PDT) Received: from fedora ([2001:250:3c1e:503:ffff:ffff:74aa:4903]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43ead3dfff3sm8344319f8f.26.2026.04.15.17.48.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2026 17:48:47 -0700 (PDT) Date: Thu, 16 Apr 2026 08:48:26 +0800 From: Ming Lei To: Aaron Tomlin Cc: Ming Lei , axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, mst@redhat.com, aacraid@microsemi.com, James.Bottomley@hansenpartnership.com, martin.petersen@oracle.com, liyihang9@h-partners.com, kashyap.desai@broadcom.com, sumit.saxena@broadcom.com, shivasharan.srikanteshwara@broadcom.com, chandrakanth.patil@broadcom.com, sathya.prakash@broadcom.com, sreekanth.reddy@broadcom.com, suganath-prabu.subramani@broadcom.com, ranjan.kumar@broadcom.com, jinpu.wang@cloud.ionos.com, tglx@kernel.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, akpm@linux-foundation.org, maz@kernel.org, ruanjinjie@huawei.com, bigeasy@linutronix.de, yphbchou0911@gmail.com, wagi@kernel.org, frederic@kernel.org, longman@redhat.com, chenridong@huawei.com, hare@suse.de, kch@nvidia.com, steve@abita.co, sean@ashe.io, chjohnst@gmail.com, neelx@suse.com, mproche@gmail.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, megaraidlinux.pdl@broadcom.com, mpi3mr-linuxdrv.pdl@broadcom.com, MPT-FusionLinux.pdl@broadcom.com Subject: Re: [PATCH v10 13/13] docs: add io_queue flag to isolcpus Message-ID: References: <6glgsbk2djsz4cqtbp2ht4274dw4rveq6fojlnpnuvx6zmpjxw@i43jo2l4qlz4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260415_174850_802366_5CF23316 X-CRM114-Status: GOOD ( 14.50 ) X-Mailman-Approved-At: Thu, 16 Apr 2026 21:42:01 -0700 X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Apr 15, 2026 at 10:56:37AM -0400, Aaron Tomlin wrote: > On Mon, Apr 13, 2026 at 11:11:15PM +0800, Ming Lei wrote: > > But typical applications aren't supposed to submit IOs from these > > isolated CPUs, so in reality, it isn't a big deal. > > Hi Ming, > > While that may be true for general-purpose workloads, it is a fundamentally > incorrect assumption for the highly specialised environments that actually > rely on strict CPU isolation, such as High-Frequency Trading (HFT). > > The requirement in these strict environments is not that the isolated CPU > performs zero I/O. Rather, the requirement is that the isolated CPU must be > shielded from the unpredictable latency of the hardware completion > interrupt. Again it is just your opinion, not a bug report, may not be a fact, right? Which kind of HFT application submits IO from isolated CPU? However, as I mentioned, I don't object this patchset, but you have to fix all wrong comment & document & bug found in review first. Thanks, Ming