From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id GCzOBjPUyWejJQcAWB0awg (envelope-from ) for ; Thu, 06 Mar 2025 11:58:27 -0500 Authentication-Results: simark.ca; dkim=pass (2048-bit key; unprotected) header.d=lists.lttng.org header.i=@lists.lttng.org header.a=rsa-sha256 header.s=default header.b=MMcEuJ2y; dkim-atps=neutral Received: by simark.ca (Postfix, from userid 112) id 16D011E105; Thu, 6 Mar 2025 11:58:27 -0500 (EST) X-Spam-Checker-Version: SpamAssassin 4.0.0 (2022-12-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-3.1 required=5.0 tests=ARC_SIGNED,ARC_VALID,BAYES_00, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=4.0.0 Received: from lists.lttng.org (lists.lttng.org [158.69.130.29]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 88F8A1E08E for ; Thu, 6 Mar 2025 11:58:26 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1741280306; bh=s8diTVK7WXoK7tepTLhsG6LZvkx3PChJgRcxxL0QADQ=; h=Date:Subject:To:References:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=MMcEuJ2ykCyIuqL3jJNBquxdmq6NBSxOUhBqBs68ZM1+f86c44vWEcMxSWWzAbEBt g1agBMrV5evPiqMPboEnkr30s622Y9cJZU0gvMEFoTaXdCSHxV5MnM61FyL+ZUaWsN 8G/1nZGd3HW5Ob+GNYSZoHAPGXy4ryo/RKpsQoelIDb4jXlsrL46okT6uI6EQ77ZAb IvgnJDqeQBp860cvOUvjuYCBkgW+yCjkdPAwuUZn5n24BnSkkv9rrYKo3g5NmiSXOM Iubl/hzi5EE8aW/CYuvZv/Ae7d0UFj+LoCJks1ejJD8jc7fGJeOTqE8gT3byQyg/oS p+vSsjXetgMgg== Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4Z7wbk26XFz1rdP; Thu, 6 Mar 2025 11:58:26 -0500 (EST) Received: from YQZPR01CU011.outbound.protection.outlook.com (mail-canadaeastazon11020116.outbound.protection.outlook.com [52.101.191.116]) by lists.lttng.org (Postfix) with ESMTPS id 4Z7wbj6XV5z1rdN for ; Thu, 6 Mar 2025 11:58:25 -0500 (EST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=QdX235XBAwSWb/L69Z9BF10RIzKO6Q2jceGz0JTdt9+aiHZNDOaaNicnA9K5/Ne6CEuAsYuhgtS3EHzYynLFRI4a8fzR+vonyO8z0iFEVVIS5MzDbeckVMNG13uIlXuqV34XJnVctiOOtP3lp+5uPNcRPmvDuigNMaVd1buM1mh3Bw5NaFYYtu94I8pN/YOVtUyCQJlWYPCDqyvHM11Fz2k34TCfhWsA2VDrJfnxeYHatCcTGugaAVXRKNPQh4WINXNWNXdnUGGN7Jc0T7RhDoRb0iAZ9V+AdAaC38cDMwunJvtgA9qNLfRQQYMaYsMOmeTeE/jAL505n5pOpomJmQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=tfHzbOxIf6BUJY9wXOOjFZWdw9guDSBmDu9XsSvHYsw=; b=XFQp/FzM/nFJrcT1tnR/JpZAy659onQWYjLJGvVoTGaxnC4S60j2CqPbe9QGvCtTmLeEslpIvMtB/8ZbnMZE4x38n6TnE7eufG4nkSy73srvv6mKwejz2iUXiPactERL0LMYuLtbDOmMUIIUF4xXRqXzKp42g5m/vZ6LGUat/m0ul5PqxaRqGC4x5NRtBWlyCIhJ4GwSXkH8lOLj8S8gAb3laVQuuWLg/kfdRNeawG1RUh0ALmX1VUYtXSf6NQeNP4702zmRpWJCGILBTnunIg756cLZSGcHpiMqIO3EZhbAu0WPlf0u31N/Twh/SvfRB3u6Yy3rXkE3eSGmGEkCjg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=efficios.com; dmarc=pass action=none header.from=efficios.com; dkim=pass header.d=efficios.com; arc=none Received: from YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:be::5) by YQBPR0101MB8140.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:5b::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8511.20; Thu, 6 Mar 2025 16:58:23 +0000 Received: from YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM ([fe80::50f1:2e3f:a5dd:5b4]) by YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM ([fe80::50f1:2e3f:a5dd:5b4%4]) with mapi id 15.20.8511.017; Thu, 6 Mar 2025 16:58:23 +0000 Message-ID: <7d25653c-5082-4632-8bc8-a387d41760e4@efficios.com> Date: Thu, 6 Mar 2025 11:58:21 -0500 User-Agent: Mozilla Thunderbird Subject: Re: need help for avoiding system calls while using URCU (Userspace RCU) To: Kienan Stewart , =?UTF-8?B?5pa56ZS0?= , lttng-dev@lists.lttng.org References: <5bfbaea6.79f9.19560340335.Coremail.fangkaihit@163.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: YQBPR0101CA0044.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c00:1::21) To YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:be::5) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: YT2PR01MB9175:EE_|YQBPR0101MB8140:EE_ X-MS-Office365-Filtering-Correlation-Id: e5ccab29-0a30-47a4-6141-08dd5cd01ae4 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|366016|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?OVVIWUFXVE14MTNmd0NJOE9pZERVSjFCYytucU1MR01nVi9PUzNtWEpudkQr?= =?utf-8?B?UGZTQS9Hc0dqSCtNRC9JUCs2YzZVcTVrTWczTDJMdlZoQWhaYVcxb1BNejd6?= =?utf-8?B?djNHenFuNTV1dXE1UVNJOFFSUEVJdmZZMFNSSCtSQURMS0RaOU8raXFodnRk?= =?utf-8?B?NTZYWjgwMkpDOFk5WVVmSG5RQk1zN29DYXh2YVk0Vm9Jdm1wbDcyUnBjTlhR?= =?utf-8?B?K1RCVGJ3OTJqUzB1b0ZOK3YwSDh4UzdKWlMySXdtVlFCQVJ4U2pqM3hjVUxG?= =?utf-8?B?QlVZeEJQMjl3NEI0ZDVwRU9BZXg5OTZsWE9QMnV4aGdDRnh5STVkbTMvQ3RC?= =?utf-8?B?VUtRam51dnZ2RjdmSTFFRUlOdzkvVFRTVUNYSXhPUFlQOXptT1ZrNmI1UitR?= =?utf-8?B?K1EweUNTV1N6TE5IbTFuMExnbGtCSUUvWDJDR2xLK3pob3BPa1Ezd1ZSK1Rm?= =?utf-8?B?dXlPVTNTKzBZVG1EVXlxRUd5Sy9mZ3B2Si91WXJnTWxyRytNZ2QzYVlhRXF6?= =?utf-8?B?Und1RGVRVGU0UFBwNTh5a2U4NitoNlJ1ZDJNZkY1ZHMraCtzWW9sQUJPd056?= =?utf-8?B?cmQybEFKS1JHcitaYkdOQk9lOEFuR2drSC9YSnB1MXQ1Sko2aUJiUlhCSUNH?= =?utf-8?B?K0FhL01NbE8yakNSYVhHNnJGQUJ1NGxkL0Erd05SaU1Jcm5HZGxMSEdzc2ow?= =?utf-8?B?ekgzcXJhZno4UTdZcjlOa2NhYTgrblZTQWlUTTJkWWRKTkRuZ0NKWSsrYzNq?= =?utf-8?B?b1N3bDdCTHc1ZUhKSEEyNmJDSWdlcU1UampyQ2xJRG1RUXR6bXk3RE9TMkJ2?= =?utf-8?B?bG43V2pTRTFSVlF4b3VEa0NvbCtHZUk3RG1Qa3M5M0NHc25iMHJ6YTNKcitx?= =?utf-8?B?QklOYVFZVkxyNU5aV3JXR2xxMFlkd1JQaXFHNEpaZWVjeTJ1ejIyOFBOT2l4?= =?utf-8?B?K2FlaGJEVGxXNk1yOFpNak80RnFoaXJzbEF2aVRRcDFraHY0V05PdTgvMHE1?= =?utf-8?B?LzE2NUZSREQvOXVhYVlNa0U3RzVpSTlkUDNnbzI4OSt0UnFpWnRrTzZ3dG9x?= =?utf-8?B?WU5ncXdXNFM4aEtNWW95dzd6YkV6MG1XejZCOGxoMWVNSUhuOGtnaG80K2la?= =?utf-8?B?V215UVpUU3djclBwY1U1bzgyYTcxRHVGeDM2eXhFNnAxcTMvelhuR1IzS3ow?= =?utf-8?B?ZnorVXVTMndDL2grUEE3dndRbHEwa1ZpL09NcXprZVcyWDRJa2ZaRExrb2Zt?= =?utf-8?B?NUU1azF4dWIwbTR3d1ZsMExHYXNKOUltRzdhMGtMNTMzUHdRRjdaZzBZdzVj?= =?utf-8?B?OVFMUkFRUlZyZnZHdjkzTnN0YUlqd0pETkd1VUZnaURiM0N3ZUhPY0NNR04x?= =?utf-8?B?SzdhcXQ5cDd0R3RLeEZtd1JRcGtEV1JaMGpHTzYwVGhZb0pOcWl3YzRUVWhD?= =?utf-8?B?RzZIaEFMbnp4NjhuRm01Q21BRHQzNi85WFc1eHh5RVUxZU1nQnpMZDZNUGw0?= =?utf-8?B?dUhhNlB2MklMdVcrOVZWeHhKUXVyYmY4Nm5kbXlEb2lHUjBiZGhOQm5XRHF1?= =?utf-8?B?Z0V6dWhHb3hSK3FKalZobGQ4YzBtd0MwYVQ3SG9SRmZGaDU1QjlMZCtQVldO?= =?utf-8?B?dVMxNVArMjcxSHpOT0thOEJFMHRCdVBOaVNYRTBFZlpkYnMydVpaZ3MvQkVR?= =?utf-8?B?bGNxcFlwZ09vRXhMdEw5UTZ3S25vVllqS1RwVWNJSndpUGFDOXU0Mjcwakp0?= =?utf-8?Q?AHVykxG27s8FMHB2jlvwHJ7eSxz4FXs6NKrxJDi?= X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM; PTR:; CAT:NONE; SFS:(13230040)(376014)(366016)(1800799024); DIR:OUT; SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?M1J1NnNqaHJibXR1TTdSdzUrRWVaNTZRR3B4dG9aVjQzVlRDWnZlcFBDQzBM?= =?utf-8?B?aE1XYldGUUM5T0ZvU3JidHg1TUc2K2dIc0Q4WlpTUzFKS1pkdVk3RlFOZWFR?= =?utf-8?B?cWJpY1YxdUxJVG5WdVUrTWdMQlgzenNWdEdkYWlNUzdQU01aejNyWW1VQ1R4?= =?utf-8?B?eEpnRWNvWmJJOWZKRFVoaTRmK1ZuMHZZT0dlN2lrOER0VzVhVkQrU3dvN2RT?= =?utf-8?B?b0UyNVV5RTVwOUVNWkwybDl5eGViNlN5YmxlU3hCaUdSWGJFNXBmbVdPVnVz?= =?utf-8?B?cXM3QmpDUFFHTHo5L2xhMWlwd0F5VGhQQzZVQ2owdXN0YzhnUnRDVmxFUzl1?= =?utf-8?B?ODZRSExGTDBscENJOGF0MWFTSW9yRHNCTVdYWWRiM280bUNnWmRMcHQrY0Y2?= =?utf-8?B?Q0Uzc2lrbWRKMFRVbitRMWhLMG5zcUtabWw4Y0NMalhDYXMvWm51TUMwUFlU?= =?utf-8?B?Q3FlWjJYUmJrL09nTVdrNmFCb01HTys1OFF3RzBwTUFzaUVGT3F3dHpzbFFv?= =?utf-8?B?eU8xQjdZYjlYZ2FsaXl5TXRHRFc4QVV1bE1Yc2RMeWdmT1YrdlBxaE9Nejlq?= =?utf-8?B?a1FCd2x0UkJxb2Q5dmxQQy8yNFNlR0pqakVUNDE5MDR2cjlyTjk3SXVlUzNw?= =?utf-8?B?cXk4NlFxWlcxcTNtSWZpMktwVEU4ckxwWmdGQm9kcGpKOURMaWFwSG5VNThi?= =?utf-8?B?aHRpY2E4b2sxUVd6REFvVGhMdkgxK2c2QVZFVnN6ZWVXdXgxeklLRHkyZHBP?= =?utf-8?B?ZWxrNXQxcXpyT1gycVJyOW9ReUFSVVZvRGJxZmhWSVpScXNQMWt4S05rdXV3?= =?utf-8?B?c2lYbCtPVzlCMmtZN2dPV25lQ3V6djVvNkdvcEI1T3hFUkhnL3lyV2w1K2Uz?= =?utf-8?B?ck5ObVRmTjRNYlJMdGwveUhzbzZmcHRlaU1rdDhuVUtUVy9mK0J2c3g0RE1u?= =?utf-8?B?QmJDMVY1dTVRZjRoZC9YR1hxL21uWEpWMnl2ZUJmYjJwUnEyOEgzTlNBQVN2?= =?utf-8?B?MHJGdVZ0emtQOGRPbFVNa3EwdXdOcGFNa0NVTEVlTG9VZTZ1a1ljb2R6UXEw?= =?utf-8?B?K2J3ZWlpam5FaDFwMlY2UlM3S1p1Y3lncFpSU2J3d1lrcG12M1pqcU1GcGt4?= =?utf-8?B?UHM1TTh4QWtFY1pReUZ2NU5QeDB2UlpDRnVNOG5LRHNxUFN4RHVXSHd5dXVN?= =?utf-8?B?bGt1V2hmWHBaWlhVcVNpOE1MRkVBS0REVE5SNUkra0ZRTFJoZkNiQWFDMklB?= =?utf-8?B?L3FNNVp4dGZENWJlWVpXTEhYV3ZXTmg4S05CeVkvb1lQa1IyYnFnTjdTcS81?= =?utf-8?B?WmtXM0FDa3JpVTdPSWZLUi8yaFc1NWIrUkRCOTBGMk9zNGNZRERHY3R2ME1z?= =?utf-8?B?NXpOWVFPVTJKTTl5Tk4xT1BIeWN6YTdGMVVkREFGb1Y3bWc1V2FubUJyRjI3?= =?utf-8?B?NVhlMlkxR2RIcGw0NDlTcytDNEYxY0pLSE1BZDBXRVZIdkhsRk9tbWNTVTZh?= =?utf-8?B?R3BaL1MyNXhtcVRPbUlxK01jamZkVjhlUGxjM1NubUx4YnorQ0VFaTEyYmVw?= =?utf-8?B?Z2NSUEdJNUcrYVkxeld5TWY2SGd4QXE3N3NHbmZIeC9GQ0R3UlVZOVhuaTBy?= =?utf-8?B?M1dQQXZZZlpWTmNneGYxSU8rWGtYTWNtKzJlOHNVOGJwZmhybmtoMitMR05k?= =?utf-8?B?S2lxaExSa2I2Vm52V1pNbkVvQ0xoUEJWTmtKZUVEelZMOU0wUFcxdWNDZ2F0?= =?utf-8?B?dkJHSkMzaUh6NGt0TXFPeTlrQ2E2NlBUdXdUNHllZDNhMUs4dGxJcTNBbFU0?= =?utf-8?B?VU1JbkhGeDdsM2VmWE10a3dYUUEzdlBWc2MrOG5YUkF0Tk9EcnU5MkRrT040?= =?utf-8?B?SWRlZmZqZGJnMWtmdXB3c3d3ZStoVHozc1B0UWlqbm40V0k5Umh6bGxTQ242?= =?utf-8?B?OGJhNGk2TXZURk0xSDQwclVvcFh2eVZtbFFZNGtETlpVdkE5bkVZL2lqQ3hJ?= =?utf-8?B?dWpFSlpDY3lTcjJhdzJKYW1sWGttNnByODkvVUdRVDZOTWhyd2U0dkx6R1Bm?= =?utf-8?B?UFFZWmN2RG1KMzBTQXBjTm1TNnRINU9iMEttc2JvYXcxYkFqa1VSMDd4QzRr?= =?utf-8?B?U3FCMUduZTArY01lZ0xLcVhVQ1B2bkFMM2RFRzlZT3l2Mk9GUEx0QTZRcFR2?= =?utf-8?Q?fcNZabPWPSxSd1UgijL6My8=3D?= X-OriginatorOrg: efficios.com X-MS-Exchange-CrossTenant-Network-Message-Id: e5ccab29-0a30-47a4-6141-08dd5cd01ae4 X-MS-Exchange-CrossTenant-AuthSource: YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Mar 2025 16:58:23.2243 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4f278736-4ab6-415c-957e-1f55336bd31e X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: aBTCQNoRpYcNakm8AxIZls1m0LYy9yZyC6JfaUWQqhOI0NRvBOmn1h3br0t7yRxM7HVQy4Ldl+uAT7eH7uESop0YuQYLtHW8oJLuYGAMaO0= X-MS-Exchange-Transport-CrossTenantHeadersStamped: YQBPR0101MB8140 X-BeenThere: lttng-dev@lists.lttng.org X-Mailman-Version: 2.1.39 Precedence: list List-Id: LTTng development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Mathieu Desnoyers via lttng-dev Reply-To: Mathieu Desnoyers Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" On 2025-03-06 11:17, Kienan Stewart via lttng-dev wrote: > Hi 方锴, > > On 3/4/25 3:09 AM, 方锴 via lttng-dev wrote: > >> I have referenced your project, URCU (Userspace RCU), on GitHub, which >> is based on the QSBR model. However, I > noticed that when using it in user mode, it makes system calls to enter > the kernel. Could you please provide guidance on how to address this issue? > > Are there specific parts of the API that you need to be user-space only? > > > I aim to achieve a pure user-mode implementation. Specifically, I > would appreciate any insights or suggestions on avoiding system calls > while still maintaining the functionality of the QSBR model in user > space. Thank you very much for your time and assistance. > > Currently the locking is done using futexs, which are system calls. Clarification: the wait/wakeup between read-side and synchronize is done using the futex system call. There is no locking on the read-side per-se. Thanks, Mathieu > Those could potentially be replaced with a poll/retry system either in a > different flavour of URCU or at build-time. > > thanks, > kienan -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com