From: Alan Stern <stern@rowland.harvard.edu>
To: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Segher Boessenkool <segher@kernel.crashing.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Andrea Parri <parri.andrea@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>,
Nick Piggin <npiggin@gmail.com>,
David Howells <dhowells@redhat.com>,
Luc Maranget <luc.maranget@inria.fr>,
Akira Yokosawa <akiyks@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-toolchains@vger.kernel.org,
linux-arch <linux-arch@vger.kernel.org>
Subject: Re: [RFC] LKMM: Add volatile_if()
Date: Fri, 6 Aug 2021 20:51:30 -0400 [thread overview]
Message-ID: <20210807005130.GA476712@rowland.harvard.edu> (raw)
In-Reply-To: <20210730172020.GA32396@knuckles.cs.ucl.ac.uk>
On Fri, Jul 30, 2021 at 06:20:22PM +0100, Jade Alglave wrote:
> I hope this material can help inform this conversation and I would love
> to hear your thoughts.
Thoughts on section 4...
The definition of Pick Basic dependency is phrased incorrectly. The
"all of the following apply" in the first paragraph refers only to first
bullet point, which in turn refers to the following two bullet points.
The "all of the following apply" phrase should be removed and the first
bullet point should be merged into the main text.
The definition of Pick dependency is redundant, because each Pick
Address and Pick Data dependency is itself already a Pick Basic
dependency. The same is true of the cat formalization.
In the cat code, the definition of Reg looks wrong. It is:
let Reg=~M | ~BR
Since (I presume) no event falls into both the M and BR classes, this
definition includes all events. It probably should be:
let Reg=~(M | BR)
or
let Reg=~M & ~BR
It's now clear that my original understanding of the underlying basis of
Intrinsic control dependencies was wrong. They aren't separated out
because CPUs can speculate through conditional branches; rather they are
separated out because they are the things which give rise to Pick
dependencies. It would have been nice if the text had explained this at
the start instead of leaving it up to me to figure out for myself.
Alan
next prev parent reply other threads:[~2021-08-07 0:51 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 10:12 [RFC] LKMM: Add volatile_if() Peter Zijlstra
2021-06-04 10:44 ` Will Deacon
2021-06-04 11:13 ` Will Deacon
2021-06-04 11:31 ` Peter Zijlstra
2021-06-04 13:44 ` Will Deacon
2021-06-04 13:56 ` Peter Zijlstra
2021-06-04 15:13 ` Will Deacon
2021-06-04 15:22 ` Peter Zijlstra
2021-06-04 15:36 ` Alan Stern
2021-06-04 15:42 ` Peter Zijlstra
2021-06-04 15:51 ` Alan Stern
2021-06-04 16:17 ` Peter Zijlstra
2021-06-04 18:27 ` Alan Stern
2021-06-04 19:09 ` Linus Torvalds
2021-06-04 19:18 ` Linus Torvalds
2021-06-04 20:56 ` Paul E. McKenney
2021-06-04 21:27 ` Linus Torvalds
2021-06-04 21:40 ` Paul E. McKenney
2021-06-04 22:19 ` Linus Torvalds
2021-06-05 14:57 ` Alan Stern
2021-06-06 0:14 ` Paul E. McKenney
2021-06-06 1:29 ` Alan Stern
2021-06-06 3:41 ` Linus Torvalds
2021-06-06 4:43 ` Paul E. McKenney
2021-06-06 13:17 ` Segher Boessenkool
2021-06-06 19:07 ` Paul E. McKenney
2021-06-06 12:59 ` Segher Boessenkool
2021-06-06 13:47 ` Alan Stern
2021-06-06 17:13 ` Segher Boessenkool
2021-06-06 18:25 ` Linus Torvalds
2021-06-06 19:19 ` Segher Boessenkool
2021-06-06 18:41 ` Alan Stern
2021-06-06 18:59 ` Jakub Jelinek
2021-06-06 19:15 ` Paul E. McKenney
2021-06-06 19:22 ` Linus Torvalds
2021-06-06 20:11 ` Segher Boessenkool
2021-06-06 21:19 ` Alexander Monakov
2021-06-06 22:38 ` Linus Torvalds
2021-06-06 23:39 ` Rasmus Villemoes
2021-06-06 23:44 ` Rasmus Villemoes
2021-06-07 8:01 ` Alexander Monakov
2021-06-07 8:27 ` Marco Elver
2021-06-07 15:28 ` Paul E. McKenney
2021-06-07 17:04 ` Marco Elver
2021-06-08 9:30 ` Marco Elver
2021-06-08 11:22 ` Peter Zijlstra
2021-06-08 15:28 ` Segher Boessenkool
2021-06-09 12:44 ` Marco Elver
2021-06-09 15:31 ` Segher Boessenkool
2021-06-09 16:13 ` Marco Elver
2021-06-09 17:14 ` Segher Boessenkool
2021-06-09 17:31 ` Nick Desaulniers
2021-06-09 20:24 ` Segher Boessenkool
2021-06-09 18:25 ` Linus Torvalds
2021-06-07 17:52 ` Segher Boessenkool
2021-06-07 18:07 ` Alexander Monakov
2021-06-07 18:18 ` Segher Boessenkool
2021-06-07 17:42 ` Segher Boessenkool
2021-06-07 20:31 ` Linus Torvalds
2021-06-07 22:54 ` Segher Boessenkool
2021-06-06 11:53 ` Segher Boessenkool
2021-06-06 13:45 ` Alan Stern
2021-06-06 18:04 ` Linus Torvalds
2021-06-06 18:22 ` Alan Stern
2021-06-06 18:43 ` Linus Torvalds
2021-06-07 10:43 ` Peter Zijlstra
2021-06-07 11:52 ` Will Deacon
2021-06-07 15:25 ` Paul E. McKenney
2021-06-07 16:02 ` Will Deacon
2021-06-07 18:08 ` Paul E. McKenney
[not found] ` <20210730172020.GA32396@knuckles.cs.ucl.ac.uk>
2021-07-30 20:35 ` Alan Stern
2021-08-02 21:18 ` Alan Stern
2021-08-02 23:31 ` Paul E. McKenney
2021-08-04 20:09 ` Alan Stern
2021-08-05 19:47 ` Alan Stern
2021-08-07 0:51 ` Alan Stern [this message]
2021-06-06 18:40 ` Segher Boessenkool
2021-06-06 18:48 ` Linus Torvalds
2021-06-06 18:53 ` Linus Torvalds
2021-06-06 19:52 ` Segher Boessenkool
2021-06-06 20:11 ` Linus Torvalds
2021-06-06 20:26 ` Segher Boessenkool
2021-06-06 23:37 ` Paul E. McKenney
2021-06-07 14:12 ` Segher Boessenkool
2021-06-07 15:27 ` Paul E. McKenney
2021-06-07 18:23 ` Segher Boessenkool
2021-06-07 19:51 ` Alan Stern
2021-06-07 20:16 ` Paul E. McKenney
2021-06-07 22:40 ` Segher Boessenkool
2021-06-07 23:26 ` Paul E. McKenney
2021-06-07 10:52 ` Peter Zijlstra
2021-06-07 14:16 ` Segher Boessenkool
2021-06-04 22:05 ` Peter Zijlstra
2021-06-05 3:14 ` Alan Stern
2021-06-05 16:24 ` Linus Torvalds
2021-06-04 15:50 ` Segher Boessenkool
2021-06-04 15:47 ` Segher Boessenkool
2021-06-04 11:44 ` Peter Zijlstra
2021-06-04 14:13 ` Paul E. McKenney
2021-06-04 15:35 ` Segher Boessenkool
2021-06-04 16:10 ` Peter Zijlstra
2021-06-04 16:40 ` Segher Boessenkool
2021-06-04 18:55 ` Paul E. McKenney
2021-06-04 19:53 ` Segher Boessenkool
2021-06-04 20:40 ` Paul E. McKenney
2021-06-06 11:36 ` Segher Boessenkool
2021-06-06 19:01 ` Paul E. McKenney
2021-06-04 14:25 ` Alan Stern
2021-06-04 16:09 ` Segher Boessenkool
2021-06-04 16:33 ` Peter Zijlstra
2021-06-04 16:30 ` Linus Torvalds
2021-06-04 16:37 ` Peter Zijlstra
2021-06-04 16:52 ` Segher Boessenkool
2021-06-04 17:10 ` Linus Torvalds
2021-06-04 17:24 ` Segher Boessenkool
2021-06-04 17:38 ` Linus Torvalds
2021-06-04 18:25 ` Segher Boessenkool
2021-06-04 19:17 ` Peter Zijlstra
2021-06-04 20:43 ` Paul E. McKenney
2021-06-04 18:23 ` Alan Stern
2021-06-08 12:48 ` David Laight
2021-09-24 18:38 ` Mathieu Desnoyers
2021-09-24 19:52 ` Alan Stern
2021-09-24 20:22 ` Mathieu Desnoyers
2021-09-24 19:55 ` Segher Boessenkool
2021-09-24 20:39 ` Mathieu Desnoyers
2021-09-24 22:07 ` Mathieu Desnoyers
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