From nobody Wed Oct 23 23:13:17 2024 X-Original-To: freebsd-arch@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4XYlGB1XrMz5ZlxK for ; Wed, 23 Oct 2024 23:13:22 +0000 (UTC) (envelope-from gnn@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R10" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4XYlG96pR8z4kQs; Wed, 23 Oct 2024 23:13:21 +0000 (UTC) (envelope-from gnn@freebsd.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1729725202; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9sUEaGHu6oajQbi+quZRflOl6oUUwXKRQLYRTZBlRoo=; b=UXkOQz28huj69MIyMAgkJDd9jPrTlmlw0tnjsLbXdl1yL6P/ygXhKFKfLJ6Oe6xbS/Tkgl z1loM3J8j/6+bgjHLhd1uT6D0eAFr8GsBaxslpr9bHqEgbRmZ+svb4Nv7QleFqddXZch7l XOsPPjpgVMYWe+Vkmx00vx/3b8QMjpNWjdwl61tIpYpCvgO9FAlV5FBX1PXurecgQG6SlQ VsHug4ozDcqgkGDc3PrVZaT1FaSsCov/S5Vh8yp/evBOuULfs8QAc7IxVCLlS4r+6QYK60 cUjkorhmOENbiUUUuFfpFVIwlqYolZj2HogmzY3Jno6mueFE0kiV6E/DjToyOQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1729725202; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9sUEaGHu6oajQbi+quZRflOl6oUUwXKRQLYRTZBlRoo=; b=KSdKoUwIr0kn0RZHRBs93U3cWmQrpO+BUFe+W9mYhqhUxWV0g9mWBFG1OXiuRGjj8AHHjK eAz1PtNj43Qoqm9pcegyC4eUrtPDSSY4dI/bjIrQ1Tq/WgMEiMP3uh/uXzrZmGS4c+G404 9v5yIa1Eow0VS4EcG9hLxHzhpFovKSISsTCX/oMMxZEC2cy3Vg9k9rtOWXUPfyqjoObYc3 belBZsUsrkfau9e8KBnF6vwicWm6fHJn/r5+JTiWB9pTlWCxrYgXOAWRxgPrBOlmMlLcJi ll4qPiMY+DLTxsEymTlfc8yNESHxQw34jfhnPFajCHk513K4TTLYsJmh2GCqgQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1729725202; a=rsa-sha256; cv=none; b=akK3Up7Uv5gtEH2i7wjd1bopoT79vveqCBSQtMmDmrh4dnMxmWXef7klTekYe14D2sFRtI IAHh4Ed8Ym8oDbaENYIwTRLyUc64GcbRmtTGI9T8RNZ9o/gtfImr8DrMksLjr4f9gxmtAG nLGPbCf7cSX1PwJ7r7wbsF34z2cZXrY35pVJv/aqUzJf+lczckF3/UHRnqr6E+l7RxCmzV coupamZt6e3TgfEOhg+H+uLoEVmiTTvp11g1wfBtR67Y5tBHeC3/SbI11ukkhHK3jFNE9t LzV9LXUifIRCV6lF13TI8T4fxoRkTpYBoT78Txd+lKwEIIvmcTjhoIlhPRrAKg== Received: from [10.101.1.66] (ip-185-104-139-70.ptr.icomera.net [185.104.139.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) (Authenticated sender: gnn) by smtp.freebsd.org (Postfix) with ESMTPSA id 4XYlG94DJvz18TH; Wed, 23 Oct 2024 23:13:21 +0000 (UTC) (envelope-from gnn@freebsd.org) From: gnn To: Vadim Goncharov Cc: Arch Subject: Re: Building kernels with FPU support? Date: Wed, 23 Oct 2024 19:13:17 -0400 X-Mailer: MailMate (1.14r5937) Message-ID: <9BC8F88D-380F-4BC0-B1C7-2657916B13BF@freebsd.org> In-Reply-To: <20241024020534.37003492@nuclight.lan> References: <20241024020534.37003492@nuclight.lan> List-Id: Discussion related to FreeBSD architecture List-Archive: https://lists.freebsd.org/archives/freebsd-arch List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arch@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On 23 Oct 2024, at 19:05, Vadim Goncharov wrote: > On Wed, 23 Oct 2024 10:38:12 -0400 > gnn wrote: > >> Howdy, >> >> I am wondering if anyone has tried, lately, to see what effect >> building with FPU support has on overall system performance. I've >> been working with a kernel module that needs this (for reasons I'll >> not go into now) and it occurred to me that the perceived performance >> overhead that caused us to only do fixed point in the kernel may no >> longer be significant. I note that Linux has an option to build >> their kernel with FPU support. >> >> And yes, I know that we have the ability to selectively deal with the >> FPU, from the calls outlined in Section 9 for fpu, but I'm asking the >> more general question of "does it matter?" and "if so, how much?" > > Would be great to have it for e.g. having portions of SQLite in kernel,= > e.g. it's R*Tree module for fast 5-dimensions lookup (like for firewall= > rules) uses floats. Funny you should mention sqlite in the kernel, since that's the exact use= case that started me down this path, and is covered in a paper I've co-a= uthored that's been accepted for publication at a database conference in = 2025. I am sure there are other use cases, we already have this on for the open= ssl module, for example. Best, George