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, HTML_MESSAGE,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 6315 invoked from network); 20 Dec 2022 03:49:41 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 20 Dec 2022 03:49:41 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 33FB342390; Tue, 20 Dec 2022 13:49:33 +1000 (AEST) Received: from mail-ed1-f46.google.com (mail-ed1-f46.google.com [209.85.208.46]) by minnie.tuhs.org (Postfix) with ESMTPS id E915442385 for ; Tue, 20 Dec 2022 13:49:27 +1000 (AEST) Received: by mail-ed1-f46.google.com with SMTP id e13so15743153edj.7 for ; Mon, 19 Dec 2022 19:49:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20210112.gappssmtp.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=NB4EDd/iBPyT4opbi1P/lacz1B5fmfVW9PQncQQnAiA=; b=Mc+vXQbtzz8sgB1CFo2m45/Jv1wBJq6TUoas08Y8kZDXtiff0f5VpgffJoI5rgX+l2 SYYEZz7swk/oGvAEenG5OJDAmjwsqPiJui9iRMX5BIv2F4Oi0MF3rH8FO59NN6NThtGR cJVsuoURoffLmo3HoB2wib8ZFKecXNi7VRvMACfon/mJaMNku5bujnWRtnNvE48fETko bBrB7m3CjJuseE8UiLF3gVqAZtAwioxf4a9OY60eAK19hIrYyBVTjOMs/KMGtq6X+MXo 0gUlup2LyJaeKkaLBaPboozT9F9PG3OleugiiJ7EecUQev0VitWQcPLa/Oidwh50aSSN AtBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=NB4EDd/iBPyT4opbi1P/lacz1B5fmfVW9PQncQQnAiA=; b=FmJA3nvYadIgrwnX819jv7BDv+TNktnJSeBkLo2XfXgbmrve71Pht1Z482HCGFipYE DqrWT0SKPOYy0tAlhbyWO7bL+HzmY0FfzMEvj3O992RRgkPkNXCeKvAGQI5kY9AE1Kz1 l7XxS/eBQ7CsPwD2A94B/zEey9yI1hKCduWYTm7/5oGPiGj30YWfC+iw6tC99Fuptrq6 nJS9LrRwFDEIw/L7mstYJu3kDlGrylmgRL3iO5xtWoqE00KpBYPIfrf0EiXwKn7Kl1Ve pNM6nukNktXzFJmETQ6Su+MRB9suGJd+9c/SyQ+Q3u0fwnce8o43eXHB2+LEv5d4y5ff BnPQ== X-Gm-Message-State: ANoB5pnv9W7EsV4wkrkidI0Md0yLTAeOWMhebb6aLgB8THK4uNOmWsVS rHNRvayryBPKplz2Did1b9XzhTF+bYCLXS10JQWs6DVz6kmZsQ== X-Google-Smtp-Source: AA0mqf4FJXh9KyE08zzVYMeFon/KL7E/jCj7TZ6u6PFE8GrC1y477ECs5rEbeWhR46BtS11W+Nol1HKWajrvT529cSM= X-Received: by 2002:a50:c012:0:b0:46c:8a01:748e with SMTP id r18-20020a50c012000000b0046c8a01748emr21954303edb.48.1671508106272; Mon, 19 Dec 2022 19:48:26 -0800 (PST) MIME-Version: 1.0 References: <202212191738.2BJHcLBF024793@ultimate.com> <94155806-907F-40EE-AB00-F3B345509442@iitbombay.org> <20221220030942.GR4401@mcvoy.com> In-Reply-To: <20221220030942.GR4401@mcvoy.com> From: Warner Losh Date: Mon, 19 Dec 2022 20:48:14 -0700 Message-ID: To: Larry McVoy Content-Type: multipart/alternative; boundary="000000000000e9f83805f03a4e14" Message-ID-Hash: ODCEQMC2S22JWCLPHIDYY5LXGN2YHUMR X-Message-ID-Hash: ODCEQMC2S22JWCLPHIDYY5LXGN2YHUMR X-MailFrom: wlosh@bsdimp.com 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: Bakul Shah , The Eunuchs Hysterical Society X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: UNIX on (not quite bare) System/370 List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --000000000000e9f83805f03a4e14 Content-Type: text/plain; charset="UTF-8" On Mon, Dec 19, 2022, 8:10 PM Larry McVoy wrote: > On Mon, Dec 19, 2022 at 06:52:47PM -0800, Bakul Shah wrote: > > On Dec 19, 2022, at 1:19 PM, Rob Pike wrote: > > > > > > Reiser and London's Unix, which I greatly admired, died on the vine > > > for a variety of political reasons, as well as because it had > > > slightly different semantics in some important cases, and because > > > of a broad antipathy to virtual memory across the company due to > > > various people having used VM on inadequate hardware, and of course > > > then there was Multics. Sandy Fraser was very nervous about > > > Research adopting the BSD kernel because of his experience with > > > Atlas. But let it be said: Reiser's VM system was seriously > > > impressive, cleanly integrated, structurally central, and > > > wonderfully fast. And Sandy relented but the general warmth of 1127 > > > towards Berkeley led to Research adopting Berkeley Unix as its VAX > > > VM platform, despite some, including myself, feeling that was > > > inferior choice. > > > > Is there a publicly available description of Reiser's VM system? > > I found "A Unix operating system for the DEC VAX 11/780 Computer" > > by London & Reiser which includes a long paragraph on VM (included > > below) but that is about it. > > > > And it would be interesting to hear why and what you found in > > Reiser's VM system that was better than Berkeley's VM system. > > Berkeley didn't really have a good VM system, other than Bill Joy > imagining it and then went on to go to Sun and inspired Joe Moran > to implement it. > The 4.2 and 4.3 VM were too vax specific. FreeBSD took Mach's VM system and while I have respect for what > Mach was trying to do, holy moly, what a mess. > To be fair, 4.4BSD had the mach vm because while Sun wanted to donate their VM, the lawyers killed the deal due to its value to the company... I'd sure rather have had the SunOS vm in 4.4BSD, but they went with what was available. The Mach VM works, but it's fit to the 4.4 kernel is imperfect. FreeBSD made it work via the early heroics of Dyson and Dillon, and the late SMP tuning of Juniper. It works, but has undergone at least 5 or 6 reorgs over the years. It also scales as all the bottlenecks have been fixed... but it could sure stand a rewrite (though that will have to wait for the next paradigm shift). NetBSD and OpenBSD adopted uvm instead maybe 5 or 10 years after 4.4 was released. This VM was initially more easily scaleable than Mach, but I'm not sure the vastly increased core counts of late work well with it. Warner I can't speak to Reiser's code because I haven't seen it, but I > can speak to Joe Moran's code, it was just so clear to see what > he was trying to do. And he did it. And you could understand it, > I did as a year out of grad school. > --000000000000e9f83805f03a4e14 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Mon, Dec 19, 2022, 8:10 PM Larry McVoy <lm@mcvoy.com> wrote:
On Mon, Dec 19, 2022 at 06:52:47PM -0800, Bakul Shah wrot= e:
> On Dec 19, 2022, at 1:19 PM, Rob Pike <robpike@gmail.com> wro= te:
> >
> > Reiser and London's Unix, which I greatly admired, died on th= e vine
> > for a variety of political reasons, as well as because it had
> > slightly different semantics in some important cases, and because=
> > of a broad antipathy to virtual memory across the company due to<= br> > > various people having used VM on inadequate hardware, and of cour= se
> > then there was Multics. Sandy Fraser was very nervous about
> > Research adopting the BSD kernel because of his experience with > > Atlas. But let it be said: Reiser's VM system was seriously > > impressive, cleanly integrated, structurally central, and
> > wonderfully fast. And Sandy relented but the general warmth of 11= 27
> > towards Berkeley led to Research adopting Berkeley Unix as its VA= X
> > VM platform, despite some, including myself, feeling that was > > inferior choice.
>
> Is there a publicly available description of Reiser's VM system? > I found "A Unix operating system for the DEC VAX 11/780 Computer&= quot;
> by London & Reiser which includes a long paragraph on VM (included=
> below) but that is about it.
>
> And it would be interesting to hear why and what you found in
> Reiser's VM system that was better than Berkeley's VM system.<= br>
Berkeley didn't really have a good VM system, other than Bill Joy
imagining it and then went on to go to Sun and inspired Joe Moran
to implement it.

The 4.2 and 4.3 VM were too vax specific.

FreeBSD took Mach's VM system and while I have respect for what
Mach was trying to do, holy moly, what a mess.
=

To be fair, 4.4BSD had the ma= ch vm because while Sun wanted to donate their VM, the lawyers killed the d= eal due to its value to the company... I'd sure rather have had the Sun= OS vm in 4.4BSD, but they went with what was available.=C2=A0 The Mach VM w= orks, but it's fit to the 4.4 kernel is imperfect.=C2=A0

FreeBSD made it work via the early he= roics of Dyson and Dillon, and the late SMP tuning of Juniper. It works, bu= t has undergone at least 5 or 6 reorgs over the years. It also scales as al= l the bottlenecks have been fixed... but it could sure stand a rewrite (tho= ugh that will have to wait for the next paradigm shift).

NetBSD and OpenBSD adopted uvm instead may= be 5 or 10 years after 4.4 was released. This VM was initially more easily = scaleable than Mach, but I'm not sure the vastly increased core counts = of late work well with it.

Warner

I can't speak to Reiser's code because I haven't seen it, but I=
can speak to Joe Moran's code, it was just so clear to see what
he was trying to do.=C2=A0 And he did it.=C2=A0 And you could understand it= ,
I did as a year out of grad school.
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