From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: caml-list@sympa.inria.fr Delivered-To: caml-list@sympa.inria.fr Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) by sympa.inria.fr (Postfix) with ESMTPS id 8E1657EC6E for ; Sun, 22 Dec 2013 04:04:42 +0100 (CET) Received-SPF: None (mail2-smtp-roc.national.inria.fr: no sender authenticity information available from domain of kosmo.zb@gmail.com) identity=pra; client-ip=209.85.212.171; receiver=mail2-smtp-roc.national.inria.fr; envelope-from="kosmo.zb@gmail.com"; x-sender="kosmo.zb@gmail.com"; x-conformance=sidf_compatible Received-SPF: Pass (mail2-smtp-roc.national.inria.fr: domain of kosmo.zb@gmail.com designates 209.85.212.171 as permitted sender) identity=mailfrom; client-ip=209.85.212.171; receiver=mail2-smtp-roc.national.inria.fr; envelope-from="kosmo.zb@gmail.com"; x-sender="kosmo.zb@gmail.com"; x-conformance=sidf_compatible; x-record-type="v=spf1" Received-SPF: None (mail2-smtp-roc.national.inria.fr: no sender authenticity information available from domain of postmaster@mail-wi0-f171.google.com) identity=helo; client-ip=209.85.212.171; receiver=mail2-smtp-roc.national.inria.fr; envelope-from="kosmo.zb@gmail.com"; x-sender="postmaster@mail-wi0-f171.google.com"; x-conformance=sidf_compatible X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av8CAFtWtlLRVdSrlGdsb2JhbABYhBi5QIEKCBYOAQEBAQcLCwkSKoIlAQEBBEABGx0BAwwGBQsNLiIBEQEFARwZh28BAxGlJYxcgwmOYwoZJw1khW4RAQUMjxkHFoQgBJgXkCcYKYRZPA X-IPAS-Result: Av8CAFtWtlLRVdSrlGdsb2JhbABYhBi5QIEKCBYOAQEBAQcLCwkSKoIlAQEBBEABGx0BAwwGBQsNLiIBEQEFARwZh28BAxGlJYxcgwmOYwoZJw1khW4RAQUMjxkHFoQgBJgXkCcYKYRZPA X-IronPort-AV: E=Sophos;i="4.95,529,1384297200"; d="scan'208";a="50040826" Received: from mail-wi0-f171.google.com ([209.85.212.171]) by mail2-smtp-roc.national.inria.fr with ESMTP/TLS/RC4-SHA; 22 Dec 2013 04:04:41 +0100 Received: by mail-wi0-f171.google.com with SMTP id bz8so9842091wib.10 for ; Sat, 21 Dec 2013 19:04:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=bQt6zmXQazOYyR9JsMhb/hNItQxInjSBfZLMLMX0lKk=; b=dzmvUtbywEkZASBFZ4p9z3jow18RuH+SGLaC2mWekYif206JCgqEE4Xx1psJcPtyeu LvVWWuMDD/2k9xn95CY+58l6pHoBN/PdAGQQ8q/ePf3xvngLXbvsOU8xJlnt9o1LrtwU OzlDEMqDgINqKIZXTr1FwfBl9OaDYK6K3rq8PaAgp3LeflUkWlSeAvEJJ8RlgUzh+Xw7 /rYIj5nO/GxWG4JEJqh5NbkZm9iEQfdctwTUeFIDJekmiCeY+tyjvKNNyJt0MEAdp8+E ONpxv7WGdKnTHhAOH5IcU4IzJ5gGxc2RAO4dA8c80jEbb9a3NKBEL/sDagk3JbKL5gIa fCaw== MIME-Version: 1.0 X-Received: by 10.180.171.34 with SMTP id ar2mr13775231wic.25.1387681481373; Sat, 21 Dec 2013 19:04:41 -0800 (PST) Received: by 10.217.9.137 with HTTP; Sat, 21 Dec 2013 19:04:41 -0800 (PST) In-Reply-To: <089e01cefebd$0e12f300$2a38d900$@ffconsultancy.com> References: <20131219224727.GA14006@annexia.org> <089e01cefebd$0e12f300$2a38d900$@ffconsultancy.com> Date: Sun, 22 Dec 2013 03:04:41 +0000 Message-ID: From: David Sheets To: jon@ffconsultancy.com Cc: "Richard W.M. Jones" , Gabriel Scherer , Tom Ridge , caml-list Content-Type: text/plain; charset=ISO-8859-1 X-Validation-by: kosmo.zb@gmail.com Subject: Re: [Caml-list] Question about garbage collection and impact on performance On Sun, Dec 22, 2013 at 2:25 AM, Jon Harrop wrote: > Richard Jones wrote: >> > My personal impression is that the question is not that well-posed: >> > - if you assume infinite memory, you don't actually need a GC (and for >> > any input you can tweak the GC setting to make sure no collection >> > happens) >> >> How could "infinite" memory be implemented without affecting the runtime > of programs on such a machine? > > I guess O(1) lookup would actually be O(n^(1/3)) due to that speed of light > thing. ;-) I think there are some fundamental limits to information density in the local universe. I reply here, though, to propose that the lookup would be O(n^(1/2)) because, locally, space is Euclidean. I'm not sure how you got the 1/3 exponent. This complexity analysis is a little weird, though, as some of your infinite memory would be arbitrarily far away and thus would suffer the square root of arbitrarily large latency. Also, your address space is infinite? Of course, the machine words are infinitely sized. It seems that even in theoretical computer science, arbitrarily large memory must be modeled as a distributed system due to the laws of physics. Perhaps I've made an error in my understanding. Please forgive and correct me, if so. Happy upswing, David