From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f47.google.com (mail-ed1-f47.google.com [209.85.208.47]) by sourceware.org (Postfix) with ESMTPS id E69DB3851C0C for ; Mon, 19 Apr 2021 21:33:15 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E69DB3851C0C Received: by mail-ed1-f47.google.com with SMTP id d21so22419769edv.9 for ; Mon, 19 Apr 2021 14:33:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=k4lZkatXb+HtS3bJ1b949kz/uK97pUNLaxlZTbtwP3E=; b=dCkYLwtpqYVOcfIQF7SeLDpQBTKLEYLvgzmS80vfhY31Bi13upkJu90vUN1J9lP/Sr 6JNLJaarZULvkGWJx7Db2V1EuwRzT36carXf8bEG0xC8FFBlnqMbzbVAVottRUXSfg+i 4uSG4lF/HFnsfVvvKkYZO9liuPHAy4PS2k5ycqZf/iCP6s0ZW2yfIzZv8CNUnzB7Tvg0 oKAwqyRPnjllVJvUH8Zl8Onk9UrmDgVvkzqR+g2fgHUm5KDSAbazU/OixVneECzy0MBg zSAZkBm6dJzfREoVpippDQV3/42LVxbKT9WPpiDP3zGqSPlz4B9V8tuWg1o0jwruPqau dDng== X-Gm-Message-State: AOAM531aJEwkPuJAimq3FTAnmkYfKHU0bLXClIgGbyxKGYH3rm6hiFGw TreVDfDrBUUy0ViUa6CGuvx5tIX3hwz0xASxWCs= X-Google-Smtp-Source: ABdhPJwuAiwQby2+1NrkYQAI2rnCBZKDhMqU9BkmsIck8t+c/F7WCEdZapDleC/COJkjawFJ8THRmajlHX9hQgHfDoM= X-Received: by 2002:a05:6402:35c9:: with SMTP id z9mr28154497edc.94.1618867994938; Mon, 19 Apr 2021 14:33:14 -0700 (PDT) MIME-Version: 1.0 References: <20210413034346.GA22861@1wt.eu> <20210414095804.GB10709@zn.tnic> <20210415044258.GA6318@zn.tnic> <20210415052938.GA2325@1wt.eu> <20210415054713.GB6318@zn.tnic> <20210419141454.GE9093@zn.tnic> <20210419191539.GH9093@zn.tnic> In-Reply-To: <20210419191539.GH9093@zn.tnic> From: Len Brown Date: Mon, 19 Apr 2021 17:33:03 -0400 Message-ID: Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related features To: Borislav Petkov Cc: Willy Tarreau , Andy Lutomirski , Florian Weimer , "Bae, Chang Seok" , Dave Hansen , X86 ML , LKML , linux-abi@vger.kernel.org, "libc-alpha@sourceware.org" , Rich Felker , Kyle Huey , Keno Fischer Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Apr 2021 21:33:17 -0000 On Mon, Apr 19, 2021 at 3:15 PM Borislav Petkov wrote: > All of a sudden you have *every* thread sporting a fat 8K buffer because > the library decided to use a fat buffer feature for it. > > Nope, I don't want that to happen. For this to happen, every thread would not only have to include/link-with code that uses AMX, but that code would have to *run*. I'm sure that the AI guys are super excited about matrix multiplication, but I have a hard time imagining why grep(1) would find a use for it. Indeed, if anyone expected AMX to be used by every task, we would have never gone to the trouble of inventing the XFD hardware to support the kernel's lazy 8KB buffer allocation. cheers, Len Brown, Intel Open Source Technology Center