From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id D369613832E for ; Fri, 19 Aug 2016 21:05:32 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 8D91EE0B7E; Fri, 19 Aug 2016 21:05:24 +0000 (UTC) Received: from mail-qk0-f196.google.com (mail-qk0-f196.google.com [209.85.220.196]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 9ABD1E0B6A for ; Fri, 19 Aug 2016 21:05:23 +0000 (UTC) Received: by mail-qk0-f196.google.com with SMTP id n66so1590572qkf.0 for ; Fri, 19 Aug 2016 14:05:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pathscale-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=MJ0Ya3PHsXeniRF/wg3xp6jtQzzzXDnR0Yf9Ve/yTVA=; b=Nc+F5ys/sbAluRnNY+A1SWKrqHX/5zCWomXEiTFalab1jVxcp3pvvRf5GbFkfV1+8k VOAKf5WptraS40Enq3123DrilYaxHkH5ygdJlcdSM6ttG6sxpZgpXPlRwSyeLKWuJoyf 5B3hoeXuQgx63jJHjHiT5e1ebKqwQXBAeJRH375PL/wOkLf1ML5sr7uRtQ9jNfk5VrHg sAFRLethkdpTMt53bAmIjUDiuNDulBd9eMFW2iOhRgeUp0c4bP+cFRLFY83i3KS8Px6l tTpbiWwnoAHXyEwBSNMOt0S8weHcf8f2XaJ8KxS9+ssnx+glhY9UYLc7R3TCG5khkBoW Pyrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=MJ0Ya3PHsXeniRF/wg3xp6jtQzzzXDnR0Yf9Ve/yTVA=; b=Yeezh4J3gjGwfrT2iSmO7EO+7HfOBb/jU93PMYtAiOAVofkwGBCRTfOfr84U9A3F2p ZW1ZVfwjEVTaY5ihVxwGufawO5K/kdnYbAf72Xm2VkWabmY6+b6CMczxXxbEZCSKE0uc mY6G4pF4IrZcm8sAhO92Qo/HsS+J6XzQ+7vStU5fTLCNlj1NZ+kNC8DodGE/FUL7iulx fmh+T8/CbABk22m1Urj0tqhVzxt8bpJKLw5Yuk2kZxJ4ueteQpU355+ujoISYBHXHBX+ cbJZu/T78bskAJddEoVQKmHAlpdLsTD4wRiOCyYwIRUPxAyJSty8zSZg9BpoxijF7P9b oslA== X-Gm-Message-State: AEkoout23gnHBxRbVTMF0h+kKjiToFMt7WFofkkBA5f000TsiGKoBSWAWvf12r824qVhDRpVAiQSex3KlxEGOw== X-Received: by 10.55.101.17 with SMTP id z17mr10911106qkb.186.1471640722401; Fri, 19 Aug 2016 14:05:22 -0700 (PDT) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 Received: by 10.140.22.6 with HTTP; Fri, 19 Aug 2016 14:05:01 -0700 (PDT) X-Originating-IP: [115.87.2.110] In-Reply-To: <905c6752-af7d-f19e-2698-b31f2ee5f89d@verizon.net> References: <20160816182204.61c27681.mgorny@gentoo.org> <20160819020737.5419083.98443.119986@pathscale.com> <36efd7a3-ce51-43ed-8aef-e1d6d79a4e5d@gentoo.org> <1b9f33d3-3807-bf55-f021-3ecfb0654c7d@verizon.net> <905c6752-af7d-f19e-2698-b31f2ee5f89d@verizon.net> From: =?UTF-8?B?QyBCZXJnc3Ryw7Zt?= Date: Sat, 20 Aug 2016 05:05:01 +0800 Message-ID: Subject: Re: [gentoo-dev] New project: LLVM To: "Anthony G. Basile" Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: 498665e2-3713-4d59-a0db-52d39fcf0dad X-Archives-Hash: 0d405a4f89f6920f6b2e5947d04fcb7f On Sat, Aug 20, 2016 at 4:52 AM, james wrote: >> Back to my own glass house.. It will take a few years, but I am trying >> to make it easier (internally) to expose in some clear way all the >> pieces which compose a fine tuning per-processor. If this was "just" >> scheduling models it would be really easy, but it's not.. Those >> latencies and other magic bits decide things like.. "should I unroll >> this loop or do something else" and then you venture into the land of >> accelerators where a custom regalloc may be what you really need and >> *nothing* off the shelf fits to meet your goals.. (projects like that >> can take 9 months and in the end only give a general 1-5% median >> performance gain..) > > > If this is your mantra, I resend the generous comments. Cray use to work > that way, milking the Petroleum Industry for tons of money, but, things have > changed and the change is accelerating, rapidly. Perhaps too much off those > Cray patents that your company owns are leaking toxins into the brain-trust > where you park? > > Vendor walk-back is sad, imho. ymmv. > > Best of luck to your company's 5-year plan.... I have no idea what on earth you were trying to say in most of your reply. I am speaking only from a compiler perspective. Nothing more and nothing less.. it may be my difficultly to describe the target level and processor specific optimization choices a compiler *must* make. Beyond not understanding your email, I found it insulting. So please keep rude comments to yourself. So again to try to explain the technical side of this - We can't and have no desire to optimize for every class of processor on the planet. We have a narrow band of focus on mostly HPC centric code patterns and processors which are are typically used in HPC workloads. I'd love to expand past this, but we're a small company and that's our niche. There's no walking back or trying to claim to be something we're not.. this is pure honest transparency. (imagine it like - do one thing and do it well) The only special note I'd add on to this - the CPU isn't where we spend most of our time tuning, it's by far more on the accelerator support.