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=-5.7 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,URIBL_BLOCKED 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 B1FFDC43461 for ; Fri, 21 May 2021 09:28:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FA176100A for ; Fri, 21 May 2021 09:28:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236247AbhEUJ3a (ORCPT ); Fri, 21 May 2021 05:29:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236507AbhEUJ3S (ORCPT ); Fri, 21 May 2021 05:29:18 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 550CAC061763; Fri, 21 May 2021 02:26:30 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1621589187; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YH3IeA3uE4Q+xSi3z5y5AVoS8ahuOw9YD3AMctxS7O0=; b=RiphfFneNCnbD6G8Lii75tG/Vq+it+xs5PzoghIEjXytCf1126mnlkbNJqigdk5MJVInxQ lMKqkSUARY3nzjofsEIEIvaOrZuOZLZDw2VfkM/XjzH06Y5zB3JWl85jUIa5NMf2QpPMu2 nuHiiBR6kZIgIvx9dGE1hP9DG6LBAmTjqNG8UHunL/0O+t5u7BEJMNBFIADdX+gRgP+Vog rTBeEICG01i5xOYBO80dYlkUBBxTfZSEt8Zr8OiMcKmmqYT8fS26srUkJhWAkTI/xukqiH GgGw20bXVU12gnejjg+x5Uj6n6+6dza5FAWXOUo+nq0BU9SK+N8NeJfeBSvOrg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1621589187; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YH3IeA3uE4Q+xSi3z5y5AVoS8ahuOw9YD3AMctxS7O0=; b=XcH8jWcpAmSlaGhTzXGoU4IyMmZXjpCi6Gh3Qo2esYoUJE1YRF6hson4GJXo1VfWgKqrMn lveu5FhtbLBIYnBw== To: Len Brown Cc: Borislav Petkov , Willy Tarreau , Andy Lutomirski , Florian Weimer , "Bae\, Chang Seok" , Dave Hansen , X86 ML , LKML , Linux API , "libc-alpha\@sourceware.org" , Rich Felker , Kyle Huey , Keno Fischer , Arjan van de Ven Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related features In-Reply-To: References: <20210415044258.GA6318@zn.tnic> <20210415052938.GA2325@1wt.eu> <20210415054713.GB6318@zn.tnic> <20210419141454.GE9093@zn.tnic> <20210419191539.GH9093@zn.tnic> <20210419215809.GJ9093@zn.tnic> <874kf11yoz.ffs@nanos.tec.linutronix.de> <87k0ntazyn.ffs@nanos.tec.linutronix.de> <87h7ixaxs9.ffs@nanos.tec.linutronix.de> Date: Fri, 21 May 2021 11:26:26 +0200 Message-ID: <87eee0bfp9.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org Len, On Thu, May 20 2021 at 17:49, Len Brown wrote: > On Thu, May 20, 2021 at 5:41 PM Thomas Gleixner wrote: >> 2) It has effects on power/thermal and therefore effects which reach >> outside of the core scope > > FWIW, this is true of *every* instruction in the CPU. > Indeed, even when the CPU is executing *no* instructions at all, > the C-state chosen by that CPU has power/thermal impacts on its peers. > > Granted, high performance instructions such as AVX-512 and TMUL > are the most extreme case. Right and we have to draw the line somewhere. >> 3) Your approach of making it unconditionally available via the >> proposed #NM prevents the OS and subsequently the system admin / >> system designer to implement fine grained control over that >> resource. >> >> And no, an opt-in approach by providing a non-mandatory >> preallocation prctl does not solve that problem. > > I'm perfectly fine with making the explicit allocation (aka opt-in) mandatory, > and enforcing it. Great! Thanks, tglx