From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Albert Cahalan <acahalan@gmail.com>
Cc: jbarnes@virtuousgeek.org, alan@lxorguk.ukuu.org.uk,
davem@davemloft.net, jeff@garzik.org, paulus@samba.org,
torvalds@osdl.org, linux-kernel@vger.kernel.org, akpm@osdl.org,
segher@kernel.crashing.org
Subject: Re: Opinion on ordering of writel vs. stores to RAM
Date: Tue, 12 Sep 2006 17:17:00 +1000 [thread overview]
Message-ID: <1158045420.15465.97.camel@localhost.localdomain> (raw)
In-Reply-To: <787b0d920609120009q7b7bf47dw9d320e838cf191a@mail.gmail.com>
> If I see an io_to_io_barrier(), how am I to tell if it is
> read to read, write to write, read to write, write to read,
> read/write to read, read/write to write, read to read/write,
> write to read/write, or read/write to read/write?
>
> Considering just reads and writes to MMIO, there are
> 9 possible types of fence. SPARC seems to cover a
> decent number of these distinctly; the instruction takes
> an immediate value as flags.
We need to decide wether a single one doing a full MMIO fence (and not
memory) is enough or if the performance different justifies maybe having
io_to_io_{wmb,rmb,mb}. I don't see any real use for more combinations.
David ? It's your call here. What do you think ?
Ben.
next prev parent reply other threads:[~2006-09-12 7:17 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-12 4:30 Opinion on ordering of writel vs. stores to RAM Albert Cahalan
2006-09-12 5:30 ` Benjamin Herrenschmidt
2006-09-12 6:04 ` Albert Cahalan
2006-09-12 6:12 ` Benjamin Herrenschmidt
2006-09-12 7:09 ` Albert Cahalan
2006-09-12 7:17 ` Benjamin Herrenschmidt [this message]
2006-09-12 7:21 ` Albert Cahalan
-- strict thread matches above, loose matches on Subject: below --
2006-09-11 5:03 Michael Chan
2006-09-11 5:21 ` Benjamin Herrenschmidt
2006-09-09 2:03 Paul Mackerras
2006-09-09 2:42 ` Linus Torvalds
2006-09-09 3:02 ` Paul Mackerras
2006-09-09 3:54 ` Linus Torvalds
2006-09-09 7:24 ` Benjamin Herrenschmidt
2006-09-09 9:34 ` David Miller
2006-09-09 9:55 ` Jeff Garzik
2006-09-09 10:08 ` David Miller
2006-09-10 17:18 ` Jesse Barnes
2006-09-10 19:35 ` Alan Cox
2006-09-10 21:25 ` Benjamin Herrenschmidt
2006-09-10 22:23 ` Alan Cox
2006-09-10 22:18 ` Benjamin Herrenschmidt
2006-09-11 13:19 ` Jes Sorensen
2006-09-10 23:35 ` Segher Boessenkool
2006-09-11 0:12 ` Benjamin Herrenschmidt
2006-09-11 0:34 ` Jesse Barnes
2006-09-11 1:04 ` Benjamin Herrenschmidt
2006-09-11 1:13 ` Segher Boessenkool
2006-09-11 1:35 ` Benjamin Herrenschmidt
2006-09-11 9:02 ` Alan Cox
2006-09-11 9:23 ` Benjamin Herrenschmidt
2006-09-11 0:25 ` Jesse Barnes
2006-09-11 0:54 ` Segher Boessenkool
2006-09-11 1:10 ` Benjamin Herrenschmidt
2006-09-11 1:48 ` Segher Boessenkool
2006-09-11 3:53 ` Benjamin Herrenschmidt
2006-09-11 18:12 ` Jesse Barnes
2006-09-11 1:00 ` Benjamin Herrenschmidt
2006-09-11 18:08 ` Jesse Barnes
2006-09-11 21:32 ` Benjamin Herrenschmidt
2006-09-10 20:01 ` Segher Boessenkool
2006-09-11 13:21 ` David Miller
2006-09-11 14:17 ` Segher Boessenkool
2006-09-12 0:32 ` David Miller
2006-09-12 0:49 ` Benjamin Herrenschmidt
2006-09-12 16:47 ` Segher Boessenkool
2006-09-12 0:54 ` Roland Dreier
2006-09-09 11:16 ` Paul Mackerras
2006-09-09 7:23 ` Benjamin Herrenschmidt
2006-09-09 9:38 ` David Miller
2006-09-09 15:09 ` Alan Cox
2006-09-10 17:19 ` Jesse Barnes
2006-09-10 17:35 ` Michael Buesch
2006-09-10 17:49 ` Linus Torvalds
2006-09-10 18:02 ` Michael Buesch
2006-09-09 15:08 ` Alan Cox
2006-09-09 18:34 ` Auke Kok
2006-09-09 19:10 ` Patrick McFarland
2006-09-09 15:06 ` Alan Cox
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