From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 25339 invoked from network); 15 Dec 2022 05:37:37 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 15 Dec 2022 05:37:37 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 1514C423EE; Thu, 15 Dec 2022 15:37:30 +1000 (AEST) Received: from mail-oi1-f180.google.com (mail-oi1-f180.google.com [209.85.167.180]) by minnie.tuhs.org (Postfix) with ESMTPS id 814AE423C0 for ; Thu, 15 Dec 2022 15:37:24 +1000 (AEST) Received: by mail-oi1-f180.google.com with SMTP id l127so4479011oia.8 for ; Wed, 14 Dec 2022 21:37:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iitbombay-org.20210112.gappssmtp.com; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=AfnAH6jU/dY9yqkcfInGWKOUKuxMWebJ2AuQM3KM8Xc=; b=5XRuPtgubm/sVmVIKFIQB0UkExIE1q4wc3IErpsHGho+O3fip+pmW9Tt7eqUaXjUug 3TenOdt2Bz7fxGCDq4JzXWCdpLJD15GTjdq01p0RG6KbkKSMGsLH0Hw6IoQh3yQWf+r/ 2GYMxMTGtPJNTgTQeXeRHXEqefcDjZvyZgN8ACldVMQhM+5mg6E9oZU3dY3eDvmV3RfK HdT9oXsBre8w1YHLo+VtpEn3Af4bN/ccBC1Et0KebbrZBD7730BuknMWUlFkZ6Od0z2Q LBYvElP0LzD2RUoE8RnJ60aJFgKv0WtwLnCE1EWoKkUvgWzdaS0RHKfnK2qdb+h5E8tZ g2tg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=AfnAH6jU/dY9yqkcfInGWKOUKuxMWebJ2AuQM3KM8Xc=; b=OGNLu0HakcFjyA9NuGeCDtVA5jIdELrjJSMD+Eyi8duZoRcmipBHXzPmQOi1nDKsD7 oCC/6mKl5kMLpoCY6bLrAwrv6ca871NH4AMTqPWxSVpEcl9mteHw996ZZH2NRH3tZjDl CkSJNuUSwhw/KgfdEJkY71MeUSYTHpUtdG0pTv/LEkfXG65HoBTsAJo9zw1ursZfWYZG G3SFqUgE5WRwWhIQtjJD9NH16NPajH0M4sk7jSlr+ywbhYs9IgA7wp8vzHLz1Ty8FuCm EgLo6D4y+wPaeHT6ixEP6J3QmjLg8NbubZLEp3470NHowujjXI+AydI6Gz7mcsXGHtN+ VMOg== X-Gm-Message-State: ANoB5pnw5vmTr5LyrWRWTln4QUUCxpF01yEQLsrW17NOxfoRCaEZNlPi +3DOUe7cJDsRxi5LhI9SkTGCqeiRS1kpyKYh X-Google-Smtp-Source: AA0mqf684EqrSwA66ZIPwfV+j1HlDrtEr5kc/RED0eNRJ+90t/pegMYw782IhHlT8imaA1JWb1uY9A== X-Received: by 2002:a54:400a:0:b0:35e:d579:b1d8 with SMTP id x10-20020a54400a000000b0035ed579b1d8mr580274oie.46.1671082583766; Wed, 14 Dec 2022 21:36:23 -0800 (PST) Received: from smtpclient.apple (107-215-223-229.lightspeed.sntcca.sbcglobal.net. [107.215.223.229]) by smtp.gmail.com with ESMTPSA id a28-20020a056808099c00b0035ba52d0efasm675967oic.52.2022.12.14.21.36.23 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Dec 2022 21:36:23 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.300.101.1.3\)) From: Bakul Shah In-Reply-To: <20221215025453.GY20511@mcvoy.com> Date: Wed, 14 Dec 2022 21:36:12 -0800 Content-Transfer-Encoding: quoted-printable Message-Id: References: <20221211200327.GC8801@mcvoy.com> <8F5B431B-3789-42C7-8E34-0B6A417B41CF@iitbombay.org> <4A770CCE-2BC9-4DA7-B3D7-71AF9A23F79E@iitbombay.org> <20221215025453.GY20511@mcvoy.com> To: Larry McVoy X-Mailer: Apple Mail (2.3731.300.101.1.3) Message-ID-Hash: RABYXBLICFD5ELVMKVE6UV4T7LUGLLPX X-Message-ID-Hash: RABYXBLICFD5ELVMKVE6UV4T7LUGLLPX X-MailFrom: bakul@iitbombay.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-tuhs.tuhs.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: The Eunuchs Hysterical Society X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: Clever code (was Re: Re: Stdin Redirect in Cu History/Alternatives? List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Don't see how unless they put multiple related services in the same address space, which reduces context switching but tends toward a monokernel (& increased coupling). Unless I am misunderstanding you. > On Dec 14, 2022, at 6:54 PM, Larry McVoy wrote: >=20 > Wasn't there some statement that QNX dropped some of these? Copy plus > context switch? >=20 > On Wed, Dec 14, 2022 at 04:29:45PM -0800, Bakul Shah wrote: >> On Dec 11, 2022, at 7:09 PM, Andrew Warkentin = wrote: >>>=20 >>> It's not necessarily true that microkernels are significantly = slower. >>=20 >> uKernels are usually quite fast as they do so little. What can be = slow >> is emulating a Unix like OS on top due to context switches. For = instance, >> a user process doing read() will have the following context switches: >>=20 >> = userProc->uK->FileSystem->uK->diskDriver->uk->FileSysem->uK->userProc >>=20 >> or worse (I didn't account for a few things). Because of this even = some >> uKernels run a few critical services + drivers in the supervisor = mode. >> But overall slowdown of such a unix emulation will very much depend = on the >> workload and also what kind of performance improvements you are = willing to >> try in a complex kernel vs same services running in user mode. >>=20 >> At present the linux kernel has about 31+ Million lines (accounting = for >> all architectures, filesystems, device drivers etc.). The FreeBSD = 13.x >> kernel is about 8.7M LoC (of which 44-45% are in device drivers). I = only >> counted .c and .h files. In contract FreeBSD 2.2.2 kernel has ~554K = LoC. >> This LoC growth is entirely understandable but I wonder how things = may >> have turned out in an alternate universe of uKernel based designs.... >=20 > --=20 > --- > Larry McVoy Retired to fishing = http://www.mcvoy.com/lm/boat