From mboxrd@z Thu Jan 1 00:00:00 1970 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 4B15DC77B72 for ; Fri, 14 Apr 2023 17:53:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229876AbjDNRxb (ORCPT ); Fri, 14 Apr 2023 13:53:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229461AbjDNRx3 (ORCPT ); Fri, 14 Apr 2023 13:53:29 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0FB11210C for ; Fri, 14 Apr 2023 10:53:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1681494807; x=1713030807; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=NGpumhDzTFB9x+sJGnn8SRI1olyAjGi0EM3Ke6PLXJA=; b=BJQ2Yq83PUJ6V7HzAAbCpK1hdF/RUoQ3V5Uao3400IOAinNv9+6EOuuZ V2tiFoNecH3NSePy1WfNdMeBlJIl0mPj7CxMgDmKS/85SpE9hwl14ygjt fWx2FBCanSmo5k1qLOM4ufF9lpvR2/QHdev5rTS3RhkzHWie/h5qQOeAB CjodpPGo6KSXF1gGQKDFlD3byv6WOQcI3L9qv8rkATIeyvwZorbjK+rdb oOgAO05SUl04MvLZ/R+CUCoshkM9koE3jo3+aGp4/GPlYWGLQU+Zhg8ZZ mNdzxcQkpTaXdk9WHDjzyWQ0wHy1OKtEFtNiD9PWJEdwIRpktLDml6aIA A==; X-IronPort-AV: E=McAfee;i="6600,9927,10680"; a="343285117" X-IronPort-AV: E=Sophos;i="5.99,197,1677571200"; d="scan'208";a="343285117" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2023 10:53:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10680"; a="754530308" X-IronPort-AV: E=Sophos;i="5.99,197,1677571200"; d="scan'208";a="754530308" Received: from linux.intel.com ([10.54.29.200]) by fmsmga008.fm.intel.com with ESMTP; 14 Apr 2023 10:53:27 -0700 Received: from [10.212.165.245] (kliang2-mobl1.ccr.corp.intel.com [10.212.165.245]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by linux.intel.com (Postfix) with ESMTPS id DE837580677; Fri, 14 Apr 2023 10:53:25 -0700 (PDT) Message-ID: <085fa11e-ea07-c148-1b32-8a09007ee12b@linux.intel.com> Date: Fri, 14 Apr 2023 13:53:24 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH 2/6] perf: Support branch events logging Content-Language: en-US To: Peter Zijlstra , Andi Kleen Cc: mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.com, eranian@google.com References: <20230410204352.1098067-1-kan.liang@linux.intel.com> <20230410204352.1098067-2-kan.liang@linux.intel.com> <20230414103832.GD83892@hirez.programming.kicks-ass.net> <1d62b865-5d31-ec36-99e0-785844f79199@linux.intel.com> <20230414145324.GB761523@hirez.programming.kicks-ass.net> <803927bb-6f74-5c09-3c18-2fd5f423287b@linux.intel.com> <20230414160945.GC761523@hirez.programming.kicks-ass.net> From: "Liang, Kan" In-Reply-To: <20230414160945.GC761523@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023-04-14 12:09 p.m., Peter Zijlstra wrote: > On Fri, Apr 14, 2023 at 11:56:41AM -0400, Liang, Kan wrote: >>> If it were to only support 4, then >>> we're in counter scheduling contraint hell again >> >> Unfortunately, yes. >> >>> and we need to somehow >>> group all these things together with the LBR event. >> >> Group will bring many limits for the usage. For example, I was told >> there could be someone wants to use it with multiplexing. > > You can create two groups, each with an LBR event, no? If we put everything in a group, that will make the enabling much simpler. I don't think the perf tool needs the order information anymore. Because the kernel enables the events one by one in a group. The kernel just need to convert the information from the counter order to the enabling order and dump to user space. But if we have two groups with LBR event, the order information is still required. Why we still want to group things? Thanks, Kan