Re: Synchronization Algorithm Verificator for C++0x

From:
"Dmitriy V'jukov" <dvyukov@gmail.com>
Newsgroups:
comp.programming.threads,comp.lang.c++
Date:
Wed, 27 Aug 2008 10:27:40 -0700 (PDT)
Message-ID:
<1feff17e-7848-45b2-b301-de2e2ee68738@e39g2000hsf.googlegroups.com>
On Aug 27, 9:02 pm, Peter Dimov <pdi...@gmail.com> wrote:

On Aug 27, 6:50 pm, "Dmitriy V'jukov" <dvyu...@gmail.com> wrote:

Does modeling of Java volatile stores/loads as C++0x seq_cst stores/
loads satisfy those requirements?


I believe that it does.


Good! Than it will be simple.

I don't get you here. There are no such synchronization actions as
volatile loads and stores in C++0x.


Yes, I used the Java meaning of volatile. I meant that Relacy can
directly implement the JMM meaning of volatile for rl::jvolatile,
instead of translating it to C++ terms first. This would allow you to
run the same algorithm expressed in Java and in C++ seq_cst and verify
whether the results match. So Relacy can give us a direct answer to
your first question above. :-)


Hmmm... It looks like vicious circle :)

Direct modeling of Java and CLI synchronization primitives I consider
as last resort. I hope that I will be able to easily model Java/CLI
primitives via C++0x primitives. Currently I add only 2 patches. First
I've described here:
http://groups.google.com/group/comp.programming.threads/msg/07c810b38be80bb=
b
And second is that every atomic RMW is followed by seq_cst fence:
T java_cli_atomic_rmw(...)
{
  T r = cpp0x_atomic_rmw(..., memory_order_seq_cst);
  cpp0x_atomic_thread_fence(memory_order_seq_cst);
  return r;
}
I think that this is intended behavior of CLI Interlocked operations,
because they based on Win32 Interlocked operations, and they are based
on x86 locked instructions :)
I am not sure about Java here. I can't find answer in language
specification and description of atomic package...

Dmitriy V'jukov

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