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([2620:10d:c092:600::1:2b54]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-471144239bdsm35086455e9.3.2025.10.16.05.03.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 16 Oct 2025 05:03:14 -0700 (PDT) Message-ID: <28a8fdc0-2693-4ff1-bcb3-2b8f67e7b794@gmail.com> Date: Thu, 16 Oct 2025 13:04:35 +0100 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] io_uring: add IORING_SETUP_NO_SQTHREAD_STATS flag to disable sqthread stats collection To: Fengnan Chang , axboe@kernel.dk, xiaobing.li@samsung.com, io-uring@vger.kernel.org Cc: Diangang Li References: <20251016114519.57780-1-changfengnan@bytedance.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: <20251016114519.57780-1-changfengnan@bytedance.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/16/25 12:45, Fengnan Chang wrote: > introduces a new flag IORING_SETUP_NO_SQTHREAD_STATS that allows > user to disable the collection of statistics in the sqthread. > When this flag is set, the getrusage() calls in the sqthread are > skipped, which can provide a small performance improvement in high > IOPS workloads. It was added for dynamically adjusting SQPOLL timeouts, at least that what the author said, but then there is only the fdinfo to access it, which is slow and unreliable, and no follow up to expose it in a better way. To be honest, I have serious doubts it has ever been used, and I'd be tempted to completely remove it out of the kernel. Fdinfo format wasn't really stable for io_uring and we can leave it printing some made up values like 100% util. If it's there for outside monitoring, that should be done with bpf, with maybe additional tracepoints. -- Pavel Begunkov