From: Hans Boehm <Hans.Boehm@hp.com>
To: Andrew Haley <aph@redhat.com>
Cc: "Boehm, Hans" <hans.boehm@hp.com>,
Java Patch List <java-patches@gcc.gnu.org>
Subject: Re: Remove data race in libgcj interpreter
Date: Sat, 06 Sep 2008 09:26:00 -0000 [thread overview]
Message-ID: <alpine.DEB.1.10.0809052200260.21567@eeepc-hansboehm> (raw)
In-Reply-To: <48C0FE20.2020103@redhat.com>
On Fri, 5 Sep 2008, Andrew Haley wrote:
> You're right, I was assuming exactly that. OK, but that is presumably
> simply a lack of volatility in the declaration of PC.
As a practical matter, that would probably help at the expense
of slowing things down a bit on some architectures. Officially this
doesn't help much, since I believe Posix allows undefined behavior
for data races, even if they involve volatiles. Even in terms of
current implementations, I don't believe it prevents hardware reordering
on architectures like PowerPC.
The C++ working paper provides atomic operations to address these issues.
I think they're even somewhat implemented in the gcc trunk. But I'm not
sure you can avoid operations that generate fences on some architectures
in what should be the fast path.
Hans
next prev parent reply other threads:[~2008-09-06 5:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-21 13:31 Andrew Haley
2008-08-21 21:54 ` Andrew Haley
2008-08-22 12:12 ` gij: more thread-safety fixes Andrew Haley
2008-08-22 12:51 ` Remove data race in libgcj interpreter Bryce McKinlay
2008-08-24 1:46 ` Andrew Haley
2008-09-04 16:00 ` Andrew Haley
2008-09-04 16:12 ` David Daney
2008-09-04 16:25 ` Andrew Haley
2008-09-04 18:37 ` David Daney
2008-09-05 9:39 ` Boehm, Hans
2008-09-05 11:28 ` Andrew Haley
2008-09-06 9:26 ` Hans Boehm [this message]
2008-09-08 17:42 ` Andrew Haley
2008-09-22 14:25 ` Andrew Haley
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