From: "Maciej W. Rozycki" <macro@orcam.me.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
Arnd Bergmann <arnd@kernel.org>,
linux-alpha@vger.kernel.org,
Richard Henderson <richard.henderson@linaro.org>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Marc Zyngier <maz@kernel.org>,
linux-kernel@vger.kernel.org, Michael Cree <mcree@orcon.net.nz>,
Frank Scheiner <frank.scheiner@web.de>
Subject: Re: [PATCH 00/14] alpha: cleanups for 6.10
Date: Thu, 4 Jul 2024 23:21:34 +0100 (BST) [thread overview]
Message-ID: <alpine.DEB.2.21.2407040044180.38148@angie.orcam.me.uk> (raw)
In-Reply-To: <CAHk-=wgncrjmWSETfPt+j6DY-MLH0=Lrd8kJHR6Tz1iJ6i39VA@mail.gmail.com>
On Tue, 2 Jul 2024, Linus Torvalds wrote:
> > Precisely my point! We got so used to think in multiples of 8 bits that
> > other approaches seem ridiculous.
>
> But Maciej - alpha *was* designed for bytes. It wasn't a Cray 1. It
> wasn't a PDP-10. It was designed by the time people knew that bytes
> were the dominant thing, and that bytes were important and the main
> use case.
>
> But it was designed BADLY. The architecture sucked.
OK, perhaps it was those people who decided to make it that way that
lived in a parallel universe.
> Give it up. If alpha had been designed in the 60s or 70s when the
> whole issue of bytes were was debatable, it would have been
> incredible.
>
> But no. It was designed for byte accesses, and it FAILED AT THEM.
I guess they decided that trading byte and word accesses for simpler bus
logic that does not have all the bits required to issue an RMW operation
to recalculate the ECC syndrome on such accesses was a good deal, and I
guess they did not realise data race implications or thought they could be
sorted in a reasonable way. The avoidance of RMWs is explicitly mentioned
in the preface to the Alpha ARM.
And I guess you are aware that getting an asynchronous multi-bit ECC
error interrupt for a partial write the origin of which has long gone and
all you have is the physical address is also a horror to handle.
Bad choice I guess anyway. Too many guesses I guess too.
Maciej
next prev parent reply other threads:[~2024-07-04 22:21 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-03 8:11 [PATCH 00/14] alpha: cleanups for 6.10 Arnd Bergmann
2024-05-03 8:11 ` [PATCH 01/14] alpha: sort scr_mem{cpy,move}w() out Arnd Bergmann
2024-05-03 8:11 ` [PATCH 02/14] alpha: fix modversions for strcpy() et.al Arnd Bergmann
2024-05-03 8:11 ` [PATCH 03/14] alpha: add clone3() support Arnd Bergmann
2024-05-03 8:11 ` [PATCH 04/14] alpha: don't make functions public without a reason Arnd Bergmann
2024-05-03 8:11 ` [PATCH 05/14] alpha: sys_sio: fix misspelled ifdefs Arnd Bergmann
2024-05-03 8:11 ` [PATCH 06/14] alpha: missing includes Arnd Bergmann
2024-05-03 8:11 ` [PATCH 07/14] alpha: core_lca: take the unused functions out Arnd Bergmann
2024-05-03 8:11 ` [PATCH 08/14] alpha: jensen, t2 - make __EXTERN_INLINE same as for the rest Arnd Bergmann
2024-05-03 8:11 ` [PATCH 09/14] alpha: trim the unused stuff from asm-offsets.c Arnd Bergmann
2024-05-03 8:11 ` [PATCH 10/14] alpha: remove DECpc AXP150 (Jensen) support Arnd Bergmann
2024-05-03 16:07 ` Linus Torvalds
2024-05-03 17:00 ` Al Viro
2024-05-03 20:07 ` Arnd Bergmann
2024-05-03 8:11 ` [PATCH 11/14] alpha: sable: remove early machine support Arnd Bergmann
2024-05-03 8:11 ` [PATCH 12/14] alpha: remove LCA and APECS based machines Arnd Bergmann
2024-05-03 8:11 ` [PATCH 13/14] alpha: cabriolet: remove EV5 CPU support Arnd Bergmann
2024-05-03 8:11 ` [PATCH 14/14] alpha: drop pre-EV56 support Arnd Bergmann
2024-05-04 15:00 ` Richard Henderson
2024-05-06 10:06 ` Arnd Bergmann
2024-06-03 6:02 ` Jiri Slaby
2024-06-04 13:58 ` Greg KH
2024-05-03 16:06 ` [PATCH 00/14] alpha: cleanups for 6.10 Matt Turner
2024-05-03 20:15 ` Arnd Bergmann
2024-05-06 9:16 ` Michael Cree
2024-05-06 10:11 ` Arnd Bergmann
2024-05-03 16:53 ` John Paul Adrian Glaubitz
2024-05-03 17:19 ` Paul E. McKenney
2024-05-27 23:49 ` Maciej W. Rozycki
2024-05-28 14:43 ` Paul E. McKenney
2024-05-29 18:50 ` Maciej W. Rozycki
2024-05-29 22:09 ` Paul E. McKenney
2024-05-30 22:59 ` Maciej W. Rozycki
2024-05-31 3:56 ` Maciej W. Rozycki
2024-05-31 19:33 ` Paul E. McKenney
2024-06-03 16:22 ` Maciej W. Rozycki
2024-06-03 17:08 ` Paul E. McKenney
2024-07-01 23:50 ` Maciej W. Rozycki
2024-05-30 1:08 ` Linus Torvalds
2024-05-30 22:57 ` Maciej W. Rozycki
2024-05-31 0:10 ` Linus Torvalds
2024-06-03 11:09 ` Maciej W. Rozycki
2024-06-03 11:36 ` John Paul Adrian Glaubitz
2024-06-03 16:57 ` Linus Torvalds
2024-07-01 23:48 ` Maciej W. Rozycki
2024-11-19 17:54 ` Maciej W. Rozycki
2024-05-31 15:48 ` Arnd Bergmann
2024-05-31 16:32 ` Linus Torvalds
2024-05-31 16:54 ` Arnd Bergmann
2024-06-01 13:51 ` David Laight
2024-07-01 23:48 ` Maciej W. Rozycki
2024-07-02 1:13 ` Linus Torvalds
2024-07-03 0:12 ` Maciej W. Rozycki
2024-07-03 0:50 ` Linus Torvalds
2024-07-04 22:21 ` Maciej W. Rozycki [this message]
2024-06-03 11:33 ` Maciej W. Rozycki
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