From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f41.google.com (mail-ed1-f41.google.com [209.85.208.41]) by sourceware.org (Postfix) with ESMTPS id 5EDEE3950C59 for ; Tue, 13 Apr 2021 19:52:03 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 5EDEE3950C59 Received: by mail-ed1-f41.google.com with SMTP id s15so20820125edd.4 for ; Tue, 13 Apr 2021 12:52:03 -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=MKPJ/sPO22gfiF94hxW9McaKDO7hAr85uineOjYitIE=; b=bmqJPI7lYUmmitiUlOW7HzKtX2F4FzVjQCWJZ6pL4CdpVEJJtSvYcZOm87oHt7it6f QTNaKhlP7hQLFOxDMuEK5Eo4NuQS1ZLZzTYDWcLFert+GJJqY6TpJMOKjtoHfmtn5/z7 h0HCMDeWHQ+fuwPq9MehG0M8kAYF8HKQ/SnWpwuPrVqqTeyZt62p8UxSqwVdWxNcYvxa +8AiEcCuBSj1ykC6q2XaWZPL79ObFkfCpwECDex2Hk+nef7jDBz4Oem3XYQUXbdPcIiY /ym6uJG4QZL9OpU+KGiBFTHZxX+AeU3eC3XsfTfdKM0zdLpgpgWMoIMTbXXhNpFIZTdg nciA== X-Gm-Message-State: AOAM530ezxha2Lxt93K9u6vssTucJfbbEfD1H0iY3Jgq71ykltHnKdQg GLk6huDbbZoNHgmT9EeVkzwCxiVBRQPNDl0qOMs= X-Google-Smtp-Source: ABdhPJzEqOYPwZS3m7LJ3+5X1Ra00fK1HTMUfkVcy19u7Iebm2WDwBUgomgbirKpn5+pkzU5Lh/OVVibfti7SdBzq0g= X-Received: by 2002:a05:6402:35c9:: with SMTP id z9mr36783451edc.94.1618343522468; Tue, 13 Apr 2021 12:52:02 -0700 (PDT) MIME-Version: 1.0 References: <87lf9nk2ku.fsf@oldenburg.str.redhat.com> <20210413034346.GA22861@1wt.eu> In-Reply-To: <20210413034346.GA22861@1wt.eu> From: Len Brown Date: Tue, 13 Apr 2021 15:51:50 -0400 Message-ID: Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related features To: Willy Tarreau Cc: 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=-1.5 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: Tue, 13 Apr 2021 19:52:04 -0000 Thanks for sharing your perspective, Willy. I agree that if your application is so sensitive that you need to hand-code your own memcmp, then linking with (any) new version of (any) dynamic library is a risk you must consider carefully. AMX does the type of matrix multiplication that AI algorithms use. In the unlikely event that you or one of the libraries you call are doing the same, then you will be very happy with AMX. Otherwise, you'll probably not use it. I acknowledge the issue with the toolchain transparently using AVX-512 for copying data, and how that approach impacted systems with a poor AVX-512 hardware implementation. FWIW. I'm not aware of any plans to implicitly use AMX this way, and I'm not aware of any non-Xeon AMX implementations in the near future. cheers, Len Brown, Intel Open Source Technology Center