From patchwork Thu Dec 8 10:59:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Niklas Cassel X-Patchwork-Id: 632149 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66C08C63705 for ; Thu, 8 Dec 2022 11:05:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229758AbiLHLEw (ORCPT ); Thu, 8 Dec 2022 06:04:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229941AbiLHLDa (ORCPT ); Thu, 8 Dec 2022 06:03:30 -0500 Received: from esa3.hgst.iphmx.com (esa3.hgst.iphmx.com [216.71.153.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D63ED8932F; Thu, 8 Dec 2022 03:01:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1670497303; x=1702033303; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=NCnbh+fwg8DrIT+FYlYEQD8y0Pfiz4OuOe484jfsh6I=; b=WF7M/M0gZYeL85DrZtTqCfCS6zkX/+m1a+msuXiVf8QOClDHFkDREDPJ Rg1QZZy89VAuhlOntB7KooyI8ORtmKhEuz9G63FGEaKBxHFkFISUy18wW QqdwUPt3yl/yePjty68Ku9HuTgdscq94KZtFSmLt13ehMOj4I//jA9dUC FYarKEGn8QAr2+SPWRa3C+H1Dpk2i6fUcb+GEUQJnLWe5MsBzFN3D82xN xO7bFVIMqt+CjWbHZTCQGnAYzk/fLO/JTkVczAn5aJFxXYyoNOx7dltQB WREEfVF5a8He+ETJvrQkziWRXYrSeZ66k0twQmGg99KFA/HWxaBU3GvX7 g==; X-IronPort-AV: E=Sophos;i="5.96,227,1665417600"; d="scan'208";a="223333440" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 08 Dec 2022 19:01:43 +0800 IronPort-SDR: iL4Xm1jd1bTg2a5A72vHqi8XeBtI03RDF+a46ZQnPaY+pk4a3XhQCJtgiZA2OLTks5kafZXKKU 7vGglxgSzpWdr7aHaOREUygpX976NJwpPG5CnI7/1Hsa79dcwH3svQZ0D/JjxuJCoq0f3grRjk E5ZlQiXQgcs0IXQenoM8SEgr4RgUMRWSqI4Tz9JqxwnRi5VX/M8pAXfWruF9Y20CZl41rVL+sc vZCzFt7ICGEL6ZvT7SoOz3m7BLzcXK1iByoFtblD4XcstAnMZB83ZyIOfg7+571dqwYC+fZbX6 tEU= Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 08 Dec 2022 02:14:28 -0800 IronPort-SDR: lH0I2LL8Td+V8zpKZDvQN2JXyuFfwFJ/WJwJHI4g3oCU4OlnnIcGij+ff7/scdguZZUCNa/fV3 oUsBUre7SroxLel2sEwxi1V83Jg+lIsxL4spr3yVrSdv0H1Zav9wKxN4Sj7goW2Uia4TE8d8vC sqcT0kHSamh1GII5KG6vz1/0ZHywU5/cpRqbSiVPJ4qpb1lhSq6plpfnDdWuweLeloSNKC4mQZ YqXRhfXkPvWAetm/yNR1oTJkSOopt0hL53YsbYGChTzrBaJGaNYg2tCMKqtr9r5o8oI61YS8n/ gkA= WDCIronportException: Internal Received: from dellx5.wdc.com (HELO x1-carbon.cphwdc) ([10.200.210.81]) by uls-op-cesaip01.wdc.com with ESMTP; 08 Dec 2022 03:01:43 -0800 From: Niklas Cassel To: linux-kernel@vger.kernel.org Cc: Hannes Reinecke , linux-scsi@vger.kernel.org, Damien Le Moal Subject: [PATCH 25/25] Documentation: sysfs-block-device: document command duration limits Date: Thu, 8 Dec 2022 11:59:41 +0100 Message-Id: <20221208105947.2399894-26-niklas.cassel@wdc.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221208105947.2399894-1-niklas.cassel@wdc.com> References: <20221208105947.2399894-1-niklas.cassel@wdc.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: Damien Le Moal Document ABI/testing/sysfs-block-device the sysfs attributes present under /sys/block/*/device/duration_limits for ATA and SCSI devices supporting the command duration limits feature. Signed-off-by: Damien Le Moal --- Documentation/ABI/testing/sysfs-block-device | 143 +++++++++++++++++++ 1 file changed, 143 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-block-device b/Documentation/ABI/testing/sysfs-block-device index 7ac7b19b2f72..44841f91c69b 100644 --- a/Documentation/ABI/testing/sysfs-block-device +++ b/Documentation/ABI/testing/sysfs-block-device @@ -95,3 +95,146 @@ Description: This file does not exist if the HBA driver does not implement support for the SATA NCQ priority feature, regardless of the device support for this feature. + + +What: /sys/block/*/device/duration_limits/enable +Date: Dec, 2022 +KernelVersion: v6.3 +Contact: linux-scsi@vger.kernel.org +Description: + (RW) For ATA and SCSI devices supporting the command duration + limits feature, write to the file to turn on or off the + feature. By default this feature is turned off. If the device + does not support the command duration limits feature, this + attribute does not exist (the directory + "/sys/block/*/device/duration_limits" does not exist). + Writing "1" to this file enables the use of command duration + limits for read and write commands in the kernel and turns on + the feature on the device. Writing "0" disables the feature. + + +What: /sys/block/*/device/duration_limits/read/[1-7]/* +Date: Dec, 2022 +KernelVersion: v6.3 +Contact: linux-scsi@vger.kernel.org +Description: + (RO) For ATA and SCSI devices supporting the command duration + limits feature, this shows the set of 7 command duration limits + descriptors for read commands currently set on the device. For + each of the 7 descritors, the following read-only attributes + are present: + + - duration_guideline: specifies the preferred length of time + in microseconds for the completion of a command. + + - duration_guideline_policy: specifies the policy action + taken if the duration_guideline attribute specifies a + non-zero command duration guideline that the device is + unable to achieve for a command. + + Possible values are: + + - 0x0: The device will complete the command at the + earliest possible time consistent with the + specified command duration guideline. + - 0x1: If the specified command duration guideline has + not been achieved and the command duration + guideline policy field is not the seventh command + duration limits descriptor, then the device + continues processing that command using the + command duration limits descriptor that has + the next higher number. + - 0x2: The device will continue processing the command + as with no command duration limits descriptor + being used. + - 0xD: The device will complete the command and an IO + failure will be reported to the user with the ETIME + error code. + - 0xF: Same as 0xD. + + - max_active_time: specifies an upper limit in microseconds + on the time that elapses from the time at which the device + initiates actions to access, transfer, or act upon the + specified data until the time the device returns status for + the command. + + - max_active_time_policy: specifies the policy action taken + if the time used to process a command exceeds a non-zero + time specified by the max_active_time attribute. + + Possible values are: + + - 0x0: The device will complete the command at the + earliest possible time (i.e, do nothing based on + the max limit not being met). + - 0xD: The device will complete the command and an IO + failure will be reported to the user with the ETIME + error code. + - 0xE: Same as 0xD. + - 0xF: Same as 0xD. + + - max_inactive_time: specifies an upper limit in microseconds + on the time that elapses from the time at which the device + receives the command until the time at which the device + initiates actions to access, transfer, or act upon the + specified data. + + - max_inactive_time_policy: specifies the policy action taken + if a non-zero max_inactive_time limit is not met. + + Possible values are: + + - 0x0: The device will complete the command at the + earliest possible time (i.e, do nothing based on + the time limit not being met). + - 0xD: The device will complete the command and an IO + failure will be reported to the user with the ETIME + error code. + - 0xF: Same as 0xD. + + +What: /sys/block/*/device/duration_limits/read/page +Date: Dec, 2022 +KernelVersion: v6.3 +Contact: linux-scsi@vger.kernel.org +Description: + (RO) For ATA and SCSI devices supporting the command duration + limits feature, this shows the name of the device VPD page + specifying the set of 7 command duration limits descriptors for + read commands. Possible values are "T2A" and "T2B". + + +What: /sys/block/*/device/duration_limits/write/[1-7]/* +Date: Dec, 2022 +KernelVersion: v6.3 +Contact: linux-scsi@vger.kernel.org +Description: + (RO) For ATA and SCSI devices supporting the command duration + limits feature, this shows the set of 7 command duration limits + descriptors for write commands currently set on the device. For + each of the 7 descritors, the same set of read-only attributes + as for read commands is present. + + +What: /sys/block/*/device/duration_limits/write/page +Date: Dec, 2022 +KernelVersion: v6.3 +Contact: linux-scsi@vger.kernel.org +Description: + (RO) For ATA and SCSI devices supporting the command duration + limits feature, this shows the name of the device VPD page + specifying the set of 7 command duration limits descriptors for + write commands. Possible values are "T2A" and "T2B". + + +What: /sys/block/*/device/duration_limits/perf_vs_duration_guideline +Date: Dec, 2022 +KernelVersion: v6.3 +Contact: linux-scsi@vger.kernel.org +Description: + (RO) For ATA and SCSI devices supporting the command duration + limits feature, this specifies the maximum percentage increase + in average command completion times (reduction in IOPS) that + is allowed for the device to perform actions based on the + contents of the duration guideline field in every command + duration limit descriptor for both read and write commands.