From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC7B11474A2 for ; Wed, 4 Sep 2024 08:01:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=205.220.177.32 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725436866; cv=fail; b=KZyW+PrLD3P9D9NxwU0ZGcwuKnfocSRPunBY2utpWHKY7kk0I3YbOo1SyzlcztRLCwkKTlfzAOkuUReTkNcM6QEqub3rQc93BSQWw5eYxcWb6tC+p/YEJ5Tw0FxWoXqFHpz+kLodO5hTUL15clo8rXgQKpgIHxn0h8HaatW5DoU= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725436866; c=relaxed/simple; bh=KXQeGzeU8zAriKtbbMaVZ2Ah95CRd9oG0MZPtLlPgdY=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: Content-Type:MIME-Version; b=aGvMsCFXl3ZknFx4ne+YO0BDYieCP1AfTeThMOrHXK6ubpnTrtbWvQcTWSUS/LLwEmvnK/5iuw7wDpBW2yZhloPjR3EpTV+2IfM91S6mssHGPlx6rTvKqSgfUpnAeEM3TdHKhGTWMSMfLtnZIFDK/fWS1SvrLxmVVFb00tp15mg= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com; spf=pass smtp.mailfrom=oracle.com; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b=agubaa51; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b=SIYL1h/Y; arc=fail smtp.client-ip=205.220.177.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oracle.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="agubaa51"; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b="SIYL1h/Y" Received: from pps.filterd (m0246631.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4841Mvim023804; Wed, 4 Sep 2024 08:00:41 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h= from:to:cc:subject:in-reply-to:references:date:message-id :content-type:content-transfer-encoding:mime-version; s= corp-2023-11-20; bh=KXQeGzeU8zAriKtbbMaVZ2Ah95CRd9oG0MZPtLlPgdY=; b= agubaa51Qmf6MHVexYQe65OhjyYbfHVeGmCBUpS17mP3qw2mC3xXY0S3DwJX1C/X VekXzokinLLRZnICPNCVmxKUhGykjo8cjE/T16twORc1MYvTNOkdnIW8UKaGsYDz vE70NsWXYeL6IJ7Vo29D17gBsc23U05azk/wHD14AXQXs0RXrcGVYOBx+SaTi93U 4DeEW1+DLU5/88oQC8kvOb8lyJOuxJzWMWsdDQWAFryTHWebpwIKlw012X5RuUoM B0Qa2cXti+eS5QDJQ86mAn3I00tiIRpMIleYzA4a3poI9EoUK/NJOAxBbVGPJm7f i29Hpo2ZzKv8SRs9n5N4dA== Received: from phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta03.appoci.oracle.com [138.1.37.129]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 41dvsaas4y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 04 Sep 2024 08:00:40 +0000 (GMT) Received: from pps.filterd (phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 4846Ellq032683; Wed, 4 Sep 2024 08:00:39 GMT Received: from nam12-dm6-obe.outbound.protection.outlook.com (mail-dm6nam12lp2175.outbound.protection.outlook.com [104.47.59.175]) by phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 41bsma0dvd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 04 Sep 2024 08:00:39 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=rTGp7nHspND1XyEO/LM5mJcwOkGSFR23ywbbuk6QCEi3oiJHuwUKqA1yf0pPmIgr6L7dhjRL0nu7n5vXk/1wNVw2mPrfJBinBTjnf0ky6LIE3JBmRaQzZb2LCIEnw93DxthWCrqp+V3h1lEV2RJwVhic1WkrsEJy+rc5UlCu5RnLTrH+NhRjOICuq/G5omqV5P5IEAzOHuvdseYYXKyzMy5ouSGJYyVQZmiVr3IG4aPGnBXvZlbgUBn1kftRQ6hSSL22QQNextyNoKSH28m8DUoG90jw1OuQDl9f5V2qEe20VkVZKPMSp9xEmIMhPEAnz3zFKxdhafj1vNqhFcfAgw== 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=KXQeGzeU8zAriKtbbMaVZ2Ah95CRd9oG0MZPtLlPgdY=; b=WUHA79emrubFK3dBS0vDUePd1PaOAdvrKL1FcVVynupP40priES2PYhe+cOlTlfBnlCl/7csAUsYKoKjRPvyjpSGefJhbdOzd/pZHeW3a5W/uPMUHCmU5RGFe7aeyxjugn9GYTupx69f7zzatx/ZAyVv49QPvZl2D4axSx2Ij3PXQYBgSY/9kdPz0uC0Z0o0HQFwqangHHMA8+pczohX1rANEOAoO0V1vEStg8gMzOcTKE0KHfs2DIJxHxsdsCVpxNYGwRbraeWeUaM9S1149HQWaRJWrS1grUWOI9baXeX1OSPf6IrkO0YUeSvsTcTn69b9acbxETgqeHEG0NxnpA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=KXQeGzeU8zAriKtbbMaVZ2Ah95CRd9oG0MZPtLlPgdY=; b=SIYL1h/YB0mV35g/Oqs9Z1P89n1EjEIRnAbqx7oDKngGm7QaFbUSdDeoyxBl4DnqaJ76NpA31UELe6qIIIuQPL3QQolyIWifxSi6U6ivJD8foHb7iDANlxzon0NtqT8xjWbT/67DEzrIcLkrURIARt2LeUTko1daFxLU+aQKrsU= Received: from LV8PR10MB7822.namprd10.prod.outlook.com (2603:10b6:408:1e8::6) by CY5PR10MB5913.namprd10.prod.outlook.com (2603:10b6:930:2f::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7918.24; Wed, 4 Sep 2024 08:00:30 +0000 Received: from LV8PR10MB7822.namprd10.prod.outlook.com ([fe80::4808:df01:d7ce:3c1e]) by LV8PR10MB7822.namprd10.prod.outlook.com ([fe80::4808:df01:d7ce:3c1e%6]) with mapi id 15.20.7918.024; Wed, 4 Sep 2024 08:00:30 +0000 From: "Jose E. Marchesi" To: Yonghong Song Cc: Daniel Borkmann , Alexei Starovoitov , Andrii Nakryiko , Martin KaFai Lau , bpf Subject: Re: Change default cpu version from v1 to v3 in llvm20 In-Reply-To: <504ced9b-b938-4cca-b108-28775404faa4@linux.dev> (Yonghong Song's message of "Tue, 3 Sep 2024 16:06:12 -0700") References: <90a00496-bcf9-358c-3b9e-e7a861728733@iogearbox.net> <504ced9b-b938-4cca-b108-28775404faa4@linux.dev> Date: Wed, 04 Sep 2024 10:00:27 +0200 Message-ID: <875xrb97c4.fsf@oracle.com> User-Agent: Gnus/5.13 (Gnus v5.13) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: FR5P281CA0011.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:f2::19) To LV8PR10MB7822.namprd10.prod.outlook.com (2603:10b6:408:1e8::6) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR10MB7822:EE_|CY5PR10MB5913:EE_ X-MS-Office365-Filtering-Correlation-Id: 26bcf1da-4711-405b-f2cd-08dcccb7a4f8 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?OEozSmNybFRGeGg1dmZMNXlUNjlaOUFVMzBTSHhrbFErK2tYU1VSTDZZSW1a?= =?utf-8?B?by9MZ3BMY1lRRytOelJsSENpbm5tZlZFb1ZveGp3NUZpeTk2Y3FaYThVK1p4?= =?utf-8?B?MmtCMTZLMUNBckNHekg3c0c0MWNBeWVjaG9kWW9uczUzSHVnZ2dzYXJlb0dV?= =?utf-8?B?VHdZZjF0c0hlZm0yTi9JekYvRXBrdkc3WW83RithaWdUQmIwQkVzU3BONmF3?= =?utf-8?B?WWh5YW9ib1UxU0liVHlCZXMydHB6cWFIWDhNVmtmUWhoU0Q5OFk4LzIwM2pV?= =?utf-8?B?Nk85S0Jlbm13RWlEOURRTlhEOXoyMlVNejVlQk03ZmRRVDdFK2NZbXdhUXQv?= =?utf-8?B?dGk1WE0wam5iaFJLNzNkQ0M5QzZseC9pNzZvOXlKL3Q4ajVQMTBPTEF2eUUv?= =?utf-8?B?RVFVejJ6Ujc0cExhMUhJSGRxK1dxamxDV3F6Q2thWnRrcEFydG5JZ1ZEMUlP?= =?utf-8?B?dkJkSnM5bXlHM2Z5SjhvRS9pb25hYjE5U1VEOU1lQURDU0w3NGYxNnBvZUlV?= =?utf-8?B?bmZoODJYUThVMmRUc3ZMOTFwMVhpZ0t3enN4bStObVdDWUhuWk9qd28rUDZY?= =?utf-8?B?Q0IvblIrZFNlVnM3eWJ5R1huc2llVEpDZE5lbENpb3lPeTQrQzlXZnVUUWNp?= =?utf-8?B?RHlMNlZYdE1rMXRCYTFzdDRRd055L1Rac25yaTczVWNVUzk1NHVQZTFLZ25Z?= =?utf-8?B?aWR3Sy9GTVN2SCtIUzh3dDNrUmoxa3d0MTBsTEZpWkZ1U29HdXVlWDE1SHNj?= =?utf-8?B?d2hsazJwSk44QkM3blluaVJKVC9vNyt2bnZ0YzZnZndQWXNYbndmd28xV3VK?= =?utf-8?B?VU1KZXBOOUFZc3VnODliQUFkRnF2OG5JVGtJeTZFY2lSNHZ0U2syZUFXVzNM?= =?utf-8?B?OHVkV0p1QldXZUIxQWZiZGczZlZzci9CeUR3RmRJU1ZqM1RrS081bVR0WHJT?= =?utf-8?B?RERYY0tKU2RGaDRUNVIrMkhld3BvK1RyKzU4akxrR1A5V0wzcXVjS3J6Uzhn?= =?utf-8?B?SG1XWGxkeXdWVzdxeHpTMHV5djFCd2VyQVd5OUtpeHNIelN1dUdYN3I3d0xy?= =?utf-8?B?NDA0MEZiUlJwNUVKOEJEZ1htN2lEa3l4VkhYSEQwTEgveXhRL2tldHlyOTFi?= =?utf-8?B?SXFQemtCRFFtelErZERNRlMraVIyeEEwcUpZL2hyRjVtVUJQTStmMFBRYzFn?= =?utf-8?B?c0djdHUvMy9DOUN4dDQzUkVqYytKZjU0eHdHbVpUcFV0MWdrMUlleDIzZkIw?= =?utf-8?B?YlpUYStZU1kwak81djhwMGo0dnp5cS92RHZHT0paeGlkVEJUUmduaEJ2TXF0?= =?utf-8?B?WGFmaXp6K2IzcGlqd3o3T1dSSXVadFRuaTYxTEhFNi8wcWlMZHRQZXluR2lT?= =?utf-8?B?TlhqZnBwRjZDTi9Md0ZsdWpleXRrcUwwc2tyVWdjRTZHRTZDZDB2eVRuTjRV?= =?utf-8?B?U3lackpXUUxHdmhwNGZUV3NlQ2Nwa1Zoek1YNmpyVUtoNkROZEhad0kzRnc1?= =?utf-8?B?OXY1TkdiWU9hSVNrM3hxd0QyTXl6MFM3d0kraUlxVlkyTlBBZUdoOWsrMVJ6?= =?utf-8?B?S2tCZmRjekh4ZzF2QmpIVmVMcERiWklCYlE3YVV4Z3RUU3ZsRFNaRHlzb2VK?= =?utf-8?B?U09pSXlkRDFOTnB6Ukp1dlRJRDhJN0prRy91ZFRDeDdoY1J1MFFWTUZQc2dB?= =?utf-8?B?WUFBSzVXQmpBNVdob0ZzU3FoWGhFVllZeDZlZDNxbENMWnFoeUlTR1lzOHJ5?= =?utf-8?Q?hZibhJthpJsW9F3+8o=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV8PR10MB7822.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(376014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?VXFjZzBBcVNFY0lHTU1xTzVMTWVjb0pkYitVL2dHZG00cDNSMlR5cU1UVXZt?= =?utf-8?B?Uk8wQitmbE12T0xGa3V5bUhiU0JSNDVuanBsc0RBeW5jQ1hxbldnMDBGelRU?= =?utf-8?B?WjJRRithRlBMcHpVZ002RzF0ZDBDMWl3VkZmTThkb1NmRVE3RnEvZUN1VGFt?= =?utf-8?B?USs2cS9QdEtvUVo1LzVJQzBIenBLUWhDaDl1ZGw2MHB3UXY2clVIS0xXemt4?= =?utf-8?B?aHJKK1k5alNxWmpENlJiNzBKUHhXcmcralhhcmdYRldaVGlpVzV1U2FPSUVE?= =?utf-8?B?ZG5qdDFHeDlpWEZOSmVsRjVNU1BMVVhNa1o2dEhCRkdXTWlhTkxoMnZHNHNu?= =?utf-8?B?YnAzWmpEMERZa090SnJPeENTMXBEYTl2czNzRUdDUzNqZDQxTGk0ZnJhOTlh?= =?utf-8?B?em82bHEyU1Z0a3gxdTV6b21vNDdIZnJMVGJrdkY5NUV5c3E2OWxBR0ZFNFQ5?= =?utf-8?B?dWNOaUs5RlpZTEhUTk83ZDVxNElGMGwvTkZpcjd0YmhiTkM4ejVheW1pcS9B?= =?utf-8?B?N1pXODQvRTd6NVpHZ0hSN2FIWFVGMWgxd3ZLVE9UVmYxRkwvSWNST3R1MmpT?= =?utf-8?B?aTM2OEkzejhXT3krZnk0OFdPRWt6U0dBMnhHeWFXR1FtMm1xUS9tSlR6SUdE?= =?utf-8?B?a3hpWU5lQUdhQURhUllFM3h2QnRBM0FNSHZPTzEzVXRCWFpsMU14TVdrWWpm?= =?utf-8?B?R2hBSjhLTytML0d0N3ZrZWhIWDdQUnEyOEtXeWdETUdPck1WN2d1bXh5Sko3?= =?utf-8?B?L3JEOUg1K2lpcG5tRDNJekZpQ09QWmVpcm8wY1ZISGVlL2xvUjR6ZnZuWEhT?= =?utf-8?B?V0xNTTN3ajJrZ1VNcmUxVjR1NzEvZ25uNzNMbmtSU3JDUTZrb1J5YmxHQjcw?= =?utf-8?B?bEJUUDNOT1prYmM0VEVNejBrck8va0ZYd1pJSzNhSDk0WTBqZTduV0dvcytG?= =?utf-8?B?a08vWC92czJwUWpPQ1hjUWdJZVlYSFhKNnBYVC93d21wS3lVN2RmYmpIM3FC?= =?utf-8?B?ajVYcTlPUXdpcWNzb0txdUF2UjJlWFNTMFlmNmI0Wit1aE4wTkhXV3pwQ2sr?= =?utf-8?B?YXZDRTR5YWFIbm8rWU5nQmsrSEFRdWQvT3o0YU9rWHJINDltdlFWTzh3N28x?= =?utf-8?B?QVBrdUFiZVZTa0YxU2xUSnhNdVZMQ3BESVo2VnRucVpJUUhhR0NydElyUWwr?= =?utf-8?B?SnpwT0pCcExXKzM2Vi9Dc0hYcHU5YUNEY3J4c2VOQVlsRndIQmhiWThpOG1K?= =?utf-8?B?VHNnRlpTdW11QmphR2FOaU5DVlAyZ3pPNDMvdlRBY3Z4dGlPeEloNldGTzJM?= =?utf-8?B?TUNkand0R2RaY0syVnpDUlNPTitrUytRYXZaSXBMenFxTzFXUEpZbEpzUEhi?= =?utf-8?B?bWd5SmRqOHlGQ1JHbThMUnBocmZHdFBwODZvdTVSbm16dFcvNEhOUTVqOUlu?= =?utf-8?B?NVFZYW5jUlc4bVBLTjcrVmVWdkZTQWdkNEFvbXB0T0svY1cxK09IeTNYN1lK?= =?utf-8?B?QytyU0xob2FYQUYvT2V5eG9zdzFmdFZZN1I5ZFE3Q3BYdVhkS3ljbjRsZXNZ?= =?utf-8?B?UmRnUGpFOWg0SXlBRFliajZEalYrVnRnbFpBNzhIWTNPSHNCdU9nU3BjU1Zm?= =?utf-8?B?U2NUL0MydmN6aTc5MVpSR0o1WERzVkNLd0xUQUlHYm5BR25rQzU3NFlSOEh4?= =?utf-8?B?QkJtckxhQjdXenN4NUk0RkowZ3grU3c3YmUvZFRKbEVrWFRzb3pDZ042dWc3?= =?utf-8?B?eGsya2owYWYyUFIvR2pjRTNXWFgxNGw3dmY4QjhEMTBYNmdIZnZJQnlnVzIz?= =?utf-8?B?S0VabWQ3amVkSENBV2RnOGhCSWcxUUFUTDM4SldRc1Y0RVNpdXMrbzZnaXRa?= =?utf-8?B?N0QxcVp6S29DeE5heFpmVHNacVRjK29kQ2RtYTM3VDVGVW9odUVqR241M3Zq?= =?utf-8?B?U1lQY2dtaXpVVkIzS2c1clRQN2cxZTJzSExiZTFkOWpqMFZMMUVYeHIrOHBw?= =?utf-8?B?akgwdldZTjgzaUlZcTZ6VnVLRXVCSzFrdFhENmdMQk03bkVncUF0aCtHUVpj?= =?utf-8?B?L0Y4S3pOSVZEckVkVkFXUDFaQk1XT0VqbGNPendMM2g0NlhpU3pYOXBNMUJW?= =?utf-8?B?U1VwN0xRb1FUNEZUcElMZytZWVh2S1hsbm1YcUUwaHRaM1VTU3JVZ3lMZGFp?= =?utf-8?B?VFE9PQ==?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 26bcf1da-4711-405b-f2cd-08dcccb7a4f8 X-MS-Exchange-CrossTenant-AuthSource: LV8PR10MB7822.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Sep 2024 08:00:30.0422 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: VJHgnmAuYE2v4nEGyOXEp1lmvHx9ZPYs3LDgi4+0zh4/szGwmGsz541UH1sXMKXyQQYNtCnHYrLUd9LcXLpkGEdyY3ablDLASjg5s5l0a+Q= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR10MB5913 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-04_05,2024-09-04_01,2024-09-02_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 spamscore=0 phishscore=0 mlxscore=0 bulkscore=0 adultscore=0 malwarescore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2407110000 definitions=main-2409040060 X-Proofpoint-ORIG-GUID: UecMyWwMQBbNko4JRp01x6TXc1I1CBPP X-Proofpoint-GUID: UecMyWwMQBbNko4JRp01x6TXc1I1CBPP > On 9/3/24 11:35 AM, Daniel Borkmann wrote: >> On 9/3/24 4:50 PM, Yonghong Song wrote: >>> On 9/2/24 11:52 PM, Daniel Borkmann wrote: >>>> On 9/3/24 6:10 AM, Yonghong Song wrote: >>>>> Hi, >>>>> >>>>> Suggested by Alexei, I put a llvm20 diff to make cpu=3Dv3 as the defa= ult >>>>> cpu version: >>>>> =C2=A0=C2=A0=C2=A0 https://github.com/llvm/llvm-project/pull/107008 >>>>> >>>>> cpu=3Dv3 has been introduced in llvm9 (2019 H2) and the kernel cpu=3D= v3 >>>>> support should be available around the same time although I >>>>> cannot remember the exact kernel version. >>>>> >>>>> There are two motivation to move cpu version default from v1 to v3. >>>>> >>>>> First, to resolve correct usage of code like >>>>> =C2=A0=C2=A0=C2=A0 (void)__sync_fetch_and_add(&ptr, value); >>>>> In cpu v1/v2, the above insn generates locked add insn, and >>>>> for cpu >=3D v3, the above insn generates atomic_fetch_add insn. >>>>> The atomic_fetch_add insn is the correct way for the eventual >>>>> insn for arm64. Otherwise, with locked add insn in arm64, >>>>> proper barrier will be missing and incorrect results may >>>>> be generated. >>>>> >>>>> Second, cpu=3Dv3 should have better performance than cpu=3Dv1 >>>>> in most cases. In Meta, several years ago, we have conducted >>>>> performance evaluation to compare v1 and v3 for major bpf >>>>> programs running in our platform and we concluded v3 is >>>>> better than v1 in most cases and in other rare cases v1 and v3 >>>>> have the same performance. So moving to v3 can help >>>>> performance too. >>>>> >>>>> If in rare cases, e.g. really old kernels, v1/v2 is the only >>>>> option, then users can set -mcpu=3Dv1 explicitly. >>>>> >>>>> Please let us know if you still have some concerns in your >>>>> setup w.r.t. cpu v1->v3 transition. >>>> >>>> Sounds good to me! Is there a place somewhere in LLVM where this >>>> can be documented for the BPF backend (along with the various >>>> extensions), so that developers can find sth in the official LLVM >>>> docs if they search the web? I see that riscv and some other archs >>>> have documentation under [0] which seems to get deployed under [1]. >>> >>> Thanks Daniel. >>> >>> Trying to have llvm doc for BPF backend has been discussed >>> before. IIRC, Fangrui Song suggested this when we tried to >>> add BPF reloc documents in Documentation/bpf/llvm_reloc.rst. >>> Eventually we added llvm_reloc.rst to kernel since this doc >>> is mostly interesting for kernel/bpf folks. We should add >>> an entry in bpf_devel_QA.rst to mention that default cpu >>> version change from v1 to v3. >>> >>> Not sure whether we should have the same doc in >>> llvm.org/docs/. Let me discuss with other folks on this. >> >> I was mostly thinking that not everyone might be looking into >> kernel docs (say, eBPF for Windows folks using LLVM), and at >> least on gcc docs/wiki you'll find information & quirks about >> gcc-bpf backend [2]. >> >> =C2=A0 [2] https://gcc.gnu.org/wiki/BPFBackEnd > > Thanks, Daniel. Eduard and I will look into this. Note that in GCC we document the BPF extensions (additional compiler options with their defaults, backend-specific built-ins, etc) in the compiler's manual, https://gcc.gnu.org/onlinedocs/gcc-14.2.0/gcc/. The wiki page is mainly for documenting the development and status. > > Yonghong > >> >>>> =C2=A0 [0] https://github.com/llvm/llvm-project/tree/main/llvm/docs >>>> =C2=A0 [1] https://llvm.org/docs/RISCV/RISCVVectorExtension.html >>>> >>>> Thanks, >>>> Daniel >>