From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (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 90AA72E88A1; Wed, 19 Nov 2025 15:37:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763566653; cv=none; b=TZJYL2xdJFpsLaJ0pg+9P019DC8ENJfMzlhVvc6vHyQidLnvsYfzb562ZwRbDuBo5GU15hJbBSPtDXp9ccMssx807JeiSWltr6BWlKujJ7WV7C4EtvuZs4ioB9B7khaz1dRLFADxOkNHlR40uJVXxvQQP/gTixRxxyVumTtfoYo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763566653; c=relaxed/simple; bh=HcxzBQLMPYHAEcgfCujXydDawdv/QxWAklRiwtaVtRI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DwnLwSEQG4wcy5cpwGWqPqDx2Y+p3E44JzAIGAYOg2N/ieJPJYuwPH2ODbqkLfnz6yoz3niL8HPahTZxtM9tPQ1hOFu0YZsOIqcvLIqFO8n9bLvjykg2S9ddTXr2ZYszetxRc9ap8b685r7pU2yUi3AOAeqShJSRnNl4UkrzYRg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=BlrT9UIj; arc=none smtp.client-ip=198.175.65.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="BlrT9UIj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1763566650; x=1795102650; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=HcxzBQLMPYHAEcgfCujXydDawdv/QxWAklRiwtaVtRI=; b=BlrT9UIjd6qbb/gNhgWsQyNwbhdd3ked18cTm8vVTDExOeGEK9G109GX zLYyO0HXR59HA5rJMy2uoxJXb5DeTSA+SxrLw7x5mLb4qiLcQqkk2RV0N UDyD/v57hHBJLRnCYR9SsKLC41+g6Apj1koRTHuWj5En/QQ2hFDfn6iG5 XNar6g2uqI6VPv05zGlhEeolNHph8WNtDetz26M87BmzUyDT9451SaciG 2nZqUovLcbvGa1VE4Mlzywf4CNX/L7enm06snSsYFc5Jnh7nQb8VqliUI SFbRJFEgV1ty/lSHb6WEsMIZzbjanT/CFLAXbD9YwrxXlARcYLwaJ94Mu w==; X-CSE-ConnectionGUID: /vjoMohJQ9KQMcJkfuZOjw== X-CSE-MsgGUID: dKTw69MNSoWjDxQHtrLVBw== X-IronPort-AV: E=McAfee;i="6800,10657,11618"; a="69464605" X-IronPort-AV: E=Sophos;i="6.19,315,1754982000"; d="scan'208";a="69464605" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Nov 2025 07:37:29 -0800 X-CSE-ConnectionGUID: O53mlel7SQSLlW5+ToW5pw== X-CSE-MsgGUID: vCqrMscuTvmyX6/+m+clSw== X-ExtLoop1: 1 Received: from tassilo.jf.intel.com (HELO tassilo) ([10.54.38.190]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Nov 2025 07:37:29 -0800 Date: Wed, 19 Nov 2025 07:37:27 -0800 From: Andi Kleen To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Adrian Hunter , "Dr. David Alan Gilbert" , Yang Li , James Clark , Thomas Falcon , Thomas Richter , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Dapeng Mi Subject: Re: [PATCH v5 3/3] perf stat: Add no-affinity flag Message-ID: References: <20251118211326.1840989-1-irogers@google.com> <20251118211326.1840989-4-irogers@google.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: > Ack. This is only adding the flag to perf stat, are the storms as much > of an issue there? Patch 2 of 3 changes it so that for a single event > we still use affinities, where a dummy and an event count as >1 event. Not sure I follow here. I thought you disabled it completely? > We have specific examples of loaded machines where the scheduling > latency causes broken metrics - the flag at least allows investigation > of issues like this. I don't mind reviewing a patch adding real time > priorities as an option. You don't need a new flag. Just run perf with real time priority with any standard wrapper tool, like chrt. The main obstacle is that you may need the capability to do that though. -Andi