Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941055AbcKXOlI convert rfc822-to-8bit (ORCPT ); Thu, 24 Nov 2016 09:41:08 -0500 Received: from mga14.intel.com ([192.55.52.115]:12271 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932712AbcKXOlG (ORCPT ); Thu, 24 Nov 2016 09:41:06 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,543,1473145200"; d="scan'208";a="790342825" From: "Liang, Kan" To: Jiri Olsa CC: Peter Zijlstra , "mingo@redhat.com" , "acme@kernel.org" , "linux-kernel@vger.kernel.org" , "alexander.shishkin@linux.intel.com" , "tglx@linutronix.de" , "namhyung@kernel.org" , "jolsa@kernel.org" , "Hunter, Adrian" , "wangnan0@huawei.com" , "mark.rutland@arm.com" , "andi@firstfloor.org" Subject: RE: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Thread-Topic: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Thread-Index: AQHSRbFTQeicWOUv7k2N38w8X4Va7aDmtLIAgAFwR5D//30HgIAAhn3Q//+D3oCAAIeQMA== Date: Thu, 24 Nov 2016 14:39:26 +0000 Message-ID: <37D7C6CF3E00A74B8858931C1DB2F07750CA2C2F@SHSMSX103.ccr.corp.intel.com> References: <1479894292-16277-1-git-send-email-kan.liang@intel.com> <1479894292-16277-2-git-send-email-kan.liang@intel.com> <20161123234122.GA19783@krava> <37D7C6CF3E00A74B8858931C1DB2F07750CA2BC9@SHSMSX103.ccr.corp.intel.com> <20161124135043.GF3092@twins.programming.kicks-ass.net> <37D7C6CF3E00A74B8858931C1DB2F07750CA2BFE@SHSMSX103.ccr.corp.intel.com> <20161124142747.GA30490@krava> In-Reply-To: <20161124142747.GA30490@krava> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiMjY5OTdjZTYtNjU3OS00NWYxLWEzYWYtZWJkNDI2YmVlN2QzIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE1LjkuNi42IiwiVHJ1c3RlZExhYmVsSGFzaCI6IlwvZ1krdStkVUlMQUxtMFhDdU9UXC9yUWRJaE5takZ0TDJFWEVrUW9TYnE0Yz0ifQ== x-ctpclassification: CTP_IC x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1313 Lines: 49 > On Thu, Nov 24, 2016 at 01:56:51PM +0000, Liang, Kan wrote: > > > > > > > > > > On Thu, Nov 24, 2016 at 01:45:28PM +0000, Liang, Kan wrote: > > > > > I think we should make this optional/configurable like the rest > > > > > of the aux events, like below.. > > > > > > > > > > > > > The overhead logging only happens when event is going to be > > > > disabled or the task is scheduling out. It should not be much and > expensive. > > > > > > > > Peter, > > > > > > > > What do you think? > > > > Should we make it configurable? > > > > > > Is there a downside to having it optional? > > > > NO. There will be no overhead information dumped into perf.data. Just > > like current implementation. > > old perf tools will get unexpected events if it's not optional > That's expected because a new record type is introduced. OK, I will make it configurable. Anyway, there is nothing to lose. :) Thanks, Kan > [root@ibm-x3650m4-01 perf]# ./perf c2c record -ag ^C[ perf record: Woken > up 1 times to write data ] > Warning: > Found 1 unknown events! > > Is this an older tool processing a perf.data file generated by a more recent > tool? > > If that is not the case, consider reporting to linux-kernel@vger.kernel.org. > > [ perf record: Captured and wrote 2.333 MB perf.data (9370 samples) ] > > > jirka