From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) (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 580FC57884; Fri, 19 Jan 2024 22:55:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.8 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705704906; cv=none; b=e91cnW/OynQTXKDN0RSvkKeYHg8NA3SIUQ74bOOa/axw24HPwkwiQuJ0XZaE8VZazbWFgABpnMMJaMB5OCQl5fKUiAQx5o8AfTfMBkv5fKSt4U8plNmMBoziFMLQIBkZKEM16cZWs4YvixyZF+32Lio5S5cQU/ylaIUp3Dwu8uE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705704906; c=relaxed/simple; bh=FCIf4jjmsCjm0WrvfocICE7muDXMamDKBfgKtLjKjoo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WDJlE7UuvY3dQSwif67J2bhfqmSl0MD93CPCvUBYktE2h4E3oMEcOZHTBwzk72hgawOMT/GVAWYFT+eTfhOKXfBNFbX6386o+BkPzHRuugo8gBDudgHmCZdGZGtpc8tpfF81XhjU9a8Mf0zgMx3YzUQIM9c8t1DvFx7Hc8+ufOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=YJFzAItI; arc=none smtp.client-ip=192.198.163.8 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="YJFzAItI" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1705704904; x=1737240904; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=FCIf4jjmsCjm0WrvfocICE7muDXMamDKBfgKtLjKjoo=; b=YJFzAItI7X9yBUy/NKhHvf13iCjNWMBNUcBdBI8wnoCYYyAZQZ/v9ofl +pYhObx2R/WL2n0sisfgIfaPlodtrKLLcfA4QEsMbzb5DYmdYQo5UkHp+ AczG+E0vRTnBwAU58oVSMYyagYH0w6cjJWGkZ5Vr/uwm/KwSCxd2MYlQ7 zdtSgRXQpFXjZv315Rukd9yZGazqp64FGIs7AHue5F3IHfyniF+frCoWF 38PcnLxlZorgVWbBldeFp77kerwykZ/kHMU23/W+KGVGs3hs7JweT5ASa HDNQHh/TYoa40Wuftr+yZqpbqh38I0noMFk21Em8VN23nZ291HAh6F3JZ w==; X-IronPort-AV: E=McAfee;i="6600,9927,10957"; a="14383183" X-IronPort-AV: E=Sophos;i="6.05,206,1701158400"; d="scan'208";a="14383183" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2024 14:55:04 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,206,1701158400"; d="scan'208";a="683998" Received: from tassilo.jf.intel.com (HELO tassilo) ([10.54.38.190]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2024 14:55:03 -0800 Date: Fri, 19 Jan 2024 14:55:01 -0800 From: Andi Kleen To: Ben Gainey Cc: "irogers@google.com" , "alexander.shishkin@linux.intel.com" , James Clark , "peterz@infradead.org" , Mark Rutland , "linux-perf-users@vger.kernel.org" , "mingo@redhat.com" , "acme@kernel.org" , "linux-kernel@vger.kernel.org" , "jolsa@kernel.org" , "namhyung@kernel.org" , "adrian.hunter@intel.com" Subject: Re: [PATCH 0/1] Support PERF_SAMPLE_READ with inherit_stat Message-ID: References: <20240119163924.2801678-1-ben.gainey@arm.com> <87a5p1kyif.fsf@linux.intel.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: > I had considered that, but given currently this perf_event_attr > configuration is not allowed, I assumed that it would require existing > tools to add support which would in effect be an opt-in. Of course, > adding a new flag to be explicit would be trivial enough if required. That's fair. Makes sense. > That said, the binary format for the mmap records / read() etc does not > change so using an unmodified tool to parse the data file will give bad > results. Therefore any workflow where "modified recording tool" can be > combined with "older / unmodified parsing tool" will break. Not sure of > the best way to handle this... presumably whenever a change is made to > the perf record format, any workflow that allows old parsers to read > new format data without version checks could fail? Admittedly this is a > "looks the same but isn't" change so harder for tools devs to spot. Any > suggestions? For perf itself we can find something. It does a couple of checks, like reserved bits in the perf_event_attr. For the general case of other parsers it's unclear. I suppose could increment the magic identifier to PERFILE3 -Andi