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s=default; t=1792738973; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=Xq4qCwWy+pbQ8iTazo3Vexd1X8qBhBcmv8Kv7kseiz0=; b=Dxav85LKlb/tMTXyGtqaG3c4uP8P8+3hLh+D+EGsJt2RHpOr2RfGhg6b9eglZjLXhmoQ6Ht2RdrfpaXZtbOoErJN07cxEp7wuNgaZBUJE9G1tn5QZBjZr10YrQ6VxyhdzH/6tFDu8sLtWgzI4+MqthVDFwJL/ieZV6Dm0lXSgl8= X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R511e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037026112;MF=kanie@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0XDLKYJo_1792738972; Received: from localhost(mailfrom:kanie@linux.alibaba.com fp:SMTPD_---0XDLKYJo_1792738972 cluster:ay36) by smtp.aliyun-inc.com; Fri, 23 Oct 2026 15:02:52 +0800 From: Guixin Liu To: Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Nilay Shroff , Daniel Wagner , Hannes Reinecke Cc: linux-nvme@lists.infradead.org Subject: [PATCH v3 3/3] nvme: document the service-time iopolicy sysfs attributes Date: Fri, 23 Oct 2026 15:02:41 +0800 Message-ID: <20261023070243.2495522-4-kanie@linux.alibaba.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20261023070243.2495522-1-kanie@linux.alibaba.com> References: <20261023070243.2495522-1-kanie@linux.alibaba.com> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261023_080317_381996_518AA19A X-CRM114-Status: GOOD ( 10.41 ) X-Spam-Score: -17.6 (-----------------) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" X-Spam-Status: No, score=-26.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 The service-time iopolicy adds two sysfs attributes to the NVMe path namespace devices: in_flight_bytes, reporting the bytes currently in flight on the path's controller, and relative_throughput, the per-path throughput weight used by the service-time estimation. Document both in the stable sysfs ABI, including the 0-100 value range, the default of 1, and the standby semantics of a relative_throughput of 0. Also add "service-time" to the accepted values of the subsystem iopolicy attribute. Signed-off-by: Guixin Liu --- Documentation/ABI/stable/sysfs-nvme | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff --git a/Documentation/ABI/stable/sysfs-nvme b/Documentation/ABI/stable/sysfs-nvme index a2f5d0710db40..0c1db84165f19 100644 --- a/Documentation/ABI/stable/sysfs-nvme +++ b/Documentation/ABI/stable/sysfs-nvme @@ -326,6 +326,28 @@ Description: currently selected path. Returns empty if iopolicy is not "numa". Requires CONFIG_NVME_MULTIPATH. +What: /sys/block/nvmeXcYnZ/in_flight_bytes +What: /sys/block/nvmeXcYnZ/relative_throughput +Date: October 2026 +KernelVersion: 7.5 +Contact: Guixin Liu +Description: + in_flight_bytes: Shows the number of bytes currently in + flight on this path's controller. Returns empty if + iopolicy is not "service-time". + Requires CONFIG_NVME_MULTIPATH. + + relative_throughput: Shows or sets the relative + throughput weight of this path's controller, which the + "service-time" iopolicy uses to estimate the path service + time as in_flight_bytes / relative_throughput. The value is + an integer in the range 0-100 and defaults to 1; assign + higher values to faster paths. A path with a value of 0 is + only selected when no path with a positive value is + available. Reading returns empty if iopolicy is not + "service-time"; writing is accepted regardless of the + active policy. Requires CONFIG_NVME_MULTIPATH. + What: /sys/block/nvmeXnY/delayed_removal_secs Date: May 2025 KernelVersion: 6.16 @@ -440,9 +462,9 @@ Contact: Hannes Reinecke Description: Shows or sets the multipath I/O path selection policy for this subsystem. Accepted values: "numa", "round-robin", - "queue-depth". Changing the policy clears all current path - selections. Only available when CONFIG_NVME_MULTIPATH is - enabled. + "queue-depth", "service-time". Changing the policy clears + all current path selections. Only available when + CONFIG_NVME_MULTIPATH is enabled. What: /sys/class/nvme-subsystem/nvme-subsysX/subsystype Date: September 2021 -- 2.43.7