From owner-freebsd-arch@FreeBSD.ORG Wed Feb 26 22:05:06 2014 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D7D2922F for ; Wed, 26 Feb 2014 22:05:06 +0000 (UTC) Received: from mail-lb0-x236.google.com (mail-lb0-x236.google.com [IPv6:2a00:1450:4010:c04::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 6068A11F3 for ; Wed, 26 Feb 2014 22:05:06 +0000 (UTC) Received: by mail-lb0-f182.google.com with SMTP id n15so1109912lbi.27 for ; Wed, 26 Feb 2014 14:05:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:content-type; bh=AMyX24j+FI6jcJuk/6ifFIyQ+3YNDiFdUe2DiS37/38=; b=VquwgrnszNlvWMeJHY/w7WpM38xiUbxJFzi0GSVPf8QbioURr5Xbnb0wpl3gJCsl4k jgY7nfNbj50ErzgVkL58IkCHevISQ239DwZJNZuTMXteaHWtWB2B9bUawsp90zM1edSt gjVtEQHzXQjLETcTvw4sBc2BZRtPvXVqhm3CGIh8M6KpagiQaU6uiTGmKfi1wvTGWfas /tClQ+t9+bo8Q9ZEkiORlj/MlKCGBClz1LYuQtC6w6z5drZWMzortI0mK49TVDYtpHF8 Rrf8gx5zLH/zubxtS133ZS5YfLoUxhKn6ExcJ42C95BHl47JDfdpdvuTaNOi5suPoSjq +RuA== MIME-Version: 1.0 X-Received: by 10.152.1.168 with SMTP id 8mr40612lan.74.1393452304588; Wed, 26 Feb 2014 14:05:04 -0800 (PST) Sender: rizzo.unipi@gmail.com Received: by 10.115.4.162 with HTTP; Wed, 26 Feb 2014 14:05:04 -0800 (PST) In-Reply-To: <20140226214816.GB92037@funkthat.com> References: <20140226214816.GB92037@funkthat.com> Date: Wed, 26 Feb 2014 14:05:04 -0800 X-Google-Sender-Auth: qumyQCqvmy08SpaLFi4CITQsnFU Message-ID: Subject: Re: small kernel kernel option... From: Luigi Rizzo To: "arch@freebsd.org" Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.17 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Feb 2014 22:05:07 -0000 On Wednesday, February 26, 2014, John-Mark Gurney wrote: > I'm about to commit a change to sha256 to speed it up, but the cost > of that speed up is an increase in code/data size from just under 1k > to almost 9k (as measured on amd64)... this increase is from unrolling > a loop.. > > Maybe we should have a global kernel option, SMALL_KERNEL, or something > similar that can be used to shrink code size for those that are trying > to build small embedded devices... > > Or do we already have this option, but I just don't know about it? > > I know 8k isn't much, but, a billion here and a billion there and pretty > soon you're talking about real money.. :) > Comments? > > It is very nice that you care about this. I am just not really sure that for such small numbers the extra data size matters much. The downside, as you can imagine, is now having to make sure that lint kernels do not trip on some "unused" warning. Cheers Luigi -- > John-Mark Gurney Voice: +1 415 225 5579 > > "All that I will do, has been done, All that I have, has not." > _______________________________________________ > freebsd-arch@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arch > To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org > " > -- -----------------------------------------+------------------------------- Prof. Luigi RIZZO, rizzo@iet.unipi.it . Dip. di Ing. dell'Informazione http://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL +39-050-2211611 . via Diotisalvi 2 Mobile +39-338-6809875 . 56122 PISA (Italy) -----------------------------------------+-------------------------------