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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23780C41604 for ; Sat, 3 Oct 2020 14:39:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD0FB206C3 for ; Sat, 3 Oct 2020 14:39:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Xh0rBWuq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725849AbgJCOjq (ORCPT ); Sat, 3 Oct 2020 10:39:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725787AbgJCOjq (ORCPT ); Sat, 3 Oct 2020 10:39:46 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1BB6C0613D0 for ; Sat, 3 Oct 2020 07:39:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ovpqGIldjsodgVCbtVP+i9x5Z/lL56OSfrqaI5z7PG0=; b=Xh0rBWuqQscGufPUfZrq5LeR8h P/TGcF6V+VbLV2mPw7ME+k2HVCfd9FaSV5/8Qxuo8hj8bnIHhQijz4cnpz/rWe5ne96VROLl2fohS d9XxAgUl8qM2rYTcAHzwHuXHRA8bX5AM1Pva5XeJVGS9IEN+j1tj9PAKw04JOnJ3DfauA2K6Qd9lo oUi1bUv1XUfvEeh58mwwYocaiyRAp0nWcViG4VK/RiKpsqeF7QYBdIlQWPz/ic6XWNmXTmti9fP7x EzP3LZSnL9DHB6gMIfeX9RziDvLdGIvkBjPlY+dbJITCtWyTAXtN8Z1srxkwxfjSWRrSwNMuSC5pW ugjDHRFQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kOih5-0000RR-1r; Sat, 03 Oct 2020 14:39:27 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 4B105302526; Sat, 3 Oct 2020 16:39:23 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 73C522B7C0E0A; Sat, 3 Oct 2020 16:39:23 +0200 (CEST) Date: Sat, 3 Oct 2020 16:39:23 +0200 From: Peter Zijlstra To: Thomas Gleixner Cc: "Luck, Tony" , Ricardo Neri , x86@kernel.org, Borislav Petkov , Ingo Molnar , Len Brown , "Ravi V. Shankar" , linux-kernel@vger.kernel.org, Andy Lutomirski , "Liang, Kan" Subject: Re: [PATCH 0/3] x86: Add initial support to discover Intel hybrid CPUs Message-ID: <20201003143923.GC2628@hirez.programming.kicks-ass.net> References: <20201002201931.2826-1-ricardo.neri-calderon@linux.intel.com> <87r1qgccku.fsf@nanos.tec.linutronix.de> <20201003021730.GA19361@agluck-desk2.amr.corp.intel.com> <87lfgnd1tm.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lfgnd1tm.fsf@nanos.tec.linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 03, 2020 at 12:46:29PM +0200, Thomas Gleixner wrote: > > There might be some model specific performance counter events that only > > apply to some cores. Or a machine check error code that is logged in the > > model specific MSCOD field of IA32_MCi_STATUS. But any and all code can run > > on any core. > > Ok. The perf side should be doable, IIRC we already have something like > that, but Peter should know better. Yes, ARM big.LITTLE has horrible hacks. Please look at them for inspiration. Also, I once started (and never found time to finish).. https://lkml.kernel.org/r/20181010104559.GO5728@hirez.programming.kicks-ass.net Kan should be aware of all this.