Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Received-SPF: TempError (protection.outlook.com: error in processing during
 lookup of arm.com: DNS Timeout)
From:   James Clark <James.Clark@arm.com>
To:     Tan Xiaojun <tanxiaojun@huawei.com>,
        Jeremy Linton <Jeremy.Linton@arm.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "acme@kernel.org" <acme@kernel.org>,
        "alexander.shishkin@linux.intel.com" 
        <alexander.shishkin@linux.intel.com>,
        "jolsa@redhat.com" <jolsa@redhat.com>,
        "namhyung@kernel.org" <namhyung@kernel.org>,
        "ak@linux.intel.com" <ak@linux.intel.com>,
        "adrian.hunter@intel.com" <adrian.hunter@intel.com>,
        "yao.jin@linux.intel.com" <yao.jin@linux.intel.com>,
        "tmricht@linux.ibm.com" <tmricht@linux.ibm.com>,
        "brueckner@linux.ibm.com" <brueckner@linux.ibm.com>,
        "songliubraving@fb.com" <songliubraving@fb.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        Kim Phillips <Kim.Phillips@amd.com>
CC:     "gengdongjiu@huawei.com" <gengdongjiu@huawei.com>,
        "wxf.wang@hisilicon.com" <wxf.wang@hisilicon.com>,
        "liwei391@huawei.com" <liwei391@huawei.com>,
        "huawei.libin@huawei.com" <huawei.libin@huawei.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-perf-users@vger.kernel.org" <linux-perf-users@vger.kernel.org>,
        Al Grant <Al.Grant@arm.com>, nd <nd@arm.com>
Subject: Re: [RFC PATCH 2/3] perf tools: Add support for "report" for some spe
 events
Thread-Topic: [RFC PATCH 2/3] perf tools: Add support for "report" for some
 spe events
Thread-Index: AQHVSRBYwzSrk8h9+0+uZFn2bs0fiabxxmkAgACaVACAWJIigIAFtiSAgAHSXoA=
Date:   Wed, 9 Oct 2019 09:48:55 +0000
Message-ID: <b7e5ca2d-8c6c-8ab8-637e-a9aaebaf62a5@arm.com>
References: <1564738813-10944-1-git-send-email-tanxiaojun@huawei.com>
 <1564738813-10944-3-git-send-email-tanxiaojun@huawei.com>
 <0ac06995-273c-034d-52a3-921ea0337be2@arm.com>
 <016c1ce8-7220-75a2-43fa-0efe150f897c@huawei.com>
 <805660ca-1cf3-4c7f-3aa2-61fed59afa8b@arm.com>
 <637836d6-c884-1a55-7730-eeb45b590d39@huawei.com>
In-Reply-To: <637836d6-c884-1a55-7730-eeb45b590d39@huawei.com>
Accept-Language: en-GB, en-US
Content-Language: en-US
Authentication-Results-Original: spf=none (sender IP is )
 smtp.mailfrom=James.Clark@arm.com; 
x-ms-exchange-messagesentrepresentingtype: 1
x-ms-publictraffictype: Email
X-MS-Office365-Filtering-Correlation-Id: 56b399ea-dcf8-46eb-1a6f-08d74c9deba6
X-MS-Office365-Filtering-HT: Tenant
X-MS-TrafficTypeDiagnostic: AM4PR0802MB2148:|AM4PR0802MB2148:|AM6PR08MB4472:
x-ms-exchange-transport-forked: True
X-Microsoft-Antispam-PRVS: <AM6PR08MB44727AAC18ACD06259BB4F91E2950@AM6PR08MB4472.eurprd08.prod.outlook.com>
x-checkrecipientrouted: true
x-ms-oob-tlc-oobclassifiers: OLM:10000;OLM:10000;
x-forefront-prvs: 018577E36E
X-Forefront-Antispam-Report-Untrusted: SFV:NSPM;SFS:(10009020)(4636009)(39860400002)(346002)(136003)(376002)(366004)(396003)(199004)(189003)(99286004)(2201001)(2616005)(86362001)(31696002)(52116002)(25786009)(14454004)(66946007)(66476007)(66556008)(64756008)(66446008)(6246003)(71200400001)(71190400001)(6512007)(486006)(31686004)(478600001)(44832011)(5660300002)(2906002)(4326008)(476003)(54906003)(66066001)(6506007)(110136005)(386003)(229853002)(76176011)(6486002)(6116002)(3846002)(36756003)(26005)(6436002)(316002)(446003)(11346002)(8676002)(8936002)(81166006)(81156014)(2501003)(7416002)(186003)(256004)(7736002)(102836004)(305945005)(921003)(1121003);DIR:OUT;SFP:1101;SCL:1;SRVR:AM4PR0802MB2148;H:AM4PR0802MB2242.eurprd08.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1;
received-spf: None (protection.outlook.com: arm.com does not designate
 permitted sender hosts)
X-MS-Exchange-SenderADCheck: 1
X-Microsoft-Antispam-Untrusted: BCL:0;
X-Microsoft-Antispam-Message-Info-Original: U/GhUXnaA9WCz7CJww/xe+2LCHTobhlFxXi86w1RCAWMQYCpUv6rbp2gEDZafYptjrQgDgzCjJQCxXsmms6m5MQupz/Pk+sD6WlO8HUu0iUfK1B+WbFUOZN/S8gWFn8cg6SnNdlXMpbbNdx9cWU9eEWhqOmpbQsCCoKtWsh/4Qata1dKLh91dM8RNyHIpRb1J1UNKzT1dtX7kZ2ty9rWBy4kKSwCufgpRfLi3f4i4+Az6BGbEDCZypzgMYPPDedUI2sJT6k/d/aaWmqvijQO2BfejUAoBzxZC4G22MG7pfFso9YsrxvMjGOLh+I+iqzKRDxluza54eAAu3WTEHhtoxqjjDeLNMNI6lSZQhhpF9R3EEpK44TND7gO8F6tJ+kl4b71dCpBAIyDC7J8ZmSOxY/iYKcH1XlqR53PdreneQ0=
Content-Type: text/plain; charset="Windows-1252"
Content-ID: <9E4071F694BA7A45891EB1DFAFE7DC78@eurprd08.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM4PR0802MB2148
Original-Authentication-Results: spf=none (sender IP is )
 smtp.mailfrom=James.Clark@arm.com; 
X-EOPAttributedMessage: 0
X-MS-Exchange-Transport-CrossTenantHeadersStripped: AM5EUR03FT049.eop-EUR03.prod.protection.outlook.com
X-Forefront-Antispam-Report: CIP:63.35.35.123;IPV:CAL;SCL:-1;CTRY:IE;EFV:NLI;SFV:NSPM;SFS:(10009020)(4636009)(346002)(39860400002)(376002)(396003)(136003)(189003)(199004)(316002)(36906005)(14454004)(36756003)(186003)(31686004)(25786009)(110136005)(8676002)(2201001)(81166006)(81156014)(305945005)(7736002)(86362001)(229853002)(6486002)(8936002)(6512007)(26005)(8746002)(76176011)(6116002)(3846002)(99286004)(23746002)(26826003)(478600001)(126002)(6506007)(446003)(11346002)(70586007)(2501003)(6246003)(450100002)(66066001)(47776003)(2616005)(5660300002)(50466002)(476003)(22756006)(356004)(2906002)(54906003)(31696002)(102836004)(76130400001)(63350400001)(336012)(386003)(486006)(4326008)(70206006)(921003)(1121003);DIR:OUT;SFP:1101;SCL:1;SRVR:AM6PR08MB4472;H:64aa7808-outbound-1.mta.getcheckrecipient.com;FPR:;SPF:TempError;LANG:en;PTR:ec2-63-35-35-123.eu-west-1.compute.amazonaws.com;MX:1;A:1;
X-MS-Office365-Filtering-Correlation-Id-Prvs: dbf12311-a892-4c07-4530-08d74c9de61d
NoDisclaimer: True
X-Forefront-PRVS: 018577E36E
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: 6KkBz24wPBoCKO+npsd1iOxDgo9pFj/MNFPsTf+BbEHp68gyPp9KH6BNK1trKkufHXOUT1CCkvlrqJMyvz+2269e8MZghuNrk44MV7WpxZV4onw8bFGg5DY1AEvxoHBSqAh2EJluxnm5ZzxoPOootDbebjoqHFzS4eGXknmba50vtQKOLPeAOnXoWwFKT4deZO4LPLcHDEG7IY2BdB1KWN5PWsu5F0iFvVfxZ5hc+W/x6n7oghyYPmU+f2CuwBqudHkWb+qvq8Sk9CaEdFvtsmXwuqtL5q61a5sn5k2Ztxd+DQG/oZ4+S4lPezOoMUv5ghCdzKGx3hGT1nNg9xV/kyqOD9VtQ470CuI/fEAAQxEgJMhves9KBGRgYzpyn59lQ6cjNQZvD6Gp3wBG6WHPqcTw+1znbrGBhYGefK1NUCU=
X-OriginatorOrg: arm.com
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Oct 2019 09:49:04.2611
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 56b399ea-dcf8-46eb-1a6f-08d74c9deba6
X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[63.35.35.123];Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR08MB4472
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Xiaojun,

> By the way, you mentioned before that you want the spe event to be in the=
 form of "event:pp" like pebs. Is that the whole framework should be made s=
imilar to pebs? Or is it just a modification to the command format?=20

We're currently still investigating if it makes sense to modify the Perf ev=
ent open syscall to use SPE when the "precise_ip" attribute is set. And the=
n synthesize samples using the SPE data when available. This would keep the=
 syscall interface more consistent between architectures.

And if tools other than Perf want more precise data, they don't have to be =
aware of SPE or any of the implementation defined details of it. For exampl=
e the 'data source' encoding can be different from one micro architecture t=
o the next. The kernel is probably the best place to handle this.

At the moment, every tool that wants to use the Perf syscall to get precise=
 data on ARM would have to be aware of SPE and implement their own decoding=
.

> For the former, this may be a bit difficult. For the latter, there is cur=
rently no modification to the record part, so "-c -F, etc." is only for ins=
tructions rather than events, so it may be misunderstood by users.
>=20
> So I haven't figured out how to do. What do you think of this?

I think the patch at the moment is a good start to make SPE more accessible=
. And the changes I mentioned above wouldn't change the fact that the raw S=
PE data would still be available via the SPE PMU. So I think continuing wit=
h the patch as-is for now is the best idea.


James