similar to: [LLVMdev] Reviving the new LLVM concurrency model

In the definition of 'monotonic' ordering, ... "If an address is written monotonically by one thread, and other threads monotonically read that address repeatedly, the other threads must eventually see the write"... Does this mean if a thread does multi-writes monotonically, monotonic reads from other threads should see all of them? But intuitively, it seems to be fine for a

C++ and Java memory models impose restrictions for locks and unlocks, such as a thread that releases a lock must acquired the lock, or the number of locks must be larger than the number of unlocks in the same thread... for enabling some optimizations, for example, simplifying trylocks (http://www.hpl.hp.com/techreports/2008/HPL-2008-56.html), and moving some instructions inside lock acquires

On Mon, Aug 22, 2011 at 11:17 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 1:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 9:55 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>> In the definition of 'monotonic' ordering, >>> ... "If an address is written

On Mon, Aug 22, 2011 at 9:55 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > In the definition of 'monotonic' ordering, > ... "If an address is written monotonically by one thread, and other > threads monotonically read that address repeatedly, the other threads > must eventually see the write"... It's supposed to mean that if you have a something

On Mon, Aug 22, 2011 at 3:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 11:17 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 1:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 9:55 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>>> In

On Mon, Aug 22, 2011 at 1:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 9:55 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> In the definition of 'monotonic' ordering, >> ... "If an address is written monotonically by one thread, and other >> threads monotonically read that address repeatedly, the other

On Mon, Aug 22, 2011 at 3:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 11:17 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 1:02 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 9:55 AM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>>> In

On Mon, Aug 22, 2011 at 7:35 PM, Jeffrey Yasskin <jyasskin at google.com> wrote: > On Mon, Aug 22, 2011 at 4:20 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 6:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>>> On

On Mon, Aug 22, 2011 at 6:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >>> <santosh.nagarakatte at gmail.com>

The current memory model section ends with the following discussions: "Note that in cases where none of the atomic intrinsics are used, this model places only one restriction on IR transformations on top of what is required for single-threaded execution: introducing a store to a byte which might not otherwise be stored to can introduce undefined behavior.... " Why is introducing

I noticed the patch was already merged into the current LLVM language reference manual with new memory instructions, fence, cmpxchg and atomicrmw. Will the instructions be available in LLVM 3.0? On Mon, Jul 18, 2011 at 8:22 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > There was some discussion a while back about adding a C++0x-style > memory model and atomics for LLVM a while

Hi all, Chandler, Owen, and I have written up a proposal for a new memory model and atomic intrinsics in LLVM, which will make it possible to support Java and the upcoming C++0x standard. The proposed changes to the LangRef are at <http://docs.google.com/View?docID=ddb4mhxz_22dz5g98dd&revision=_latest>, and a rationale for some of the more surprising changes is at

On Sun, Jul 31, 2011 at 3:04 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > The current memory model section ends with the following discussions: > > "Note that in cases where none of the atomic intrinsics are used, this > model places only one restriction on IR transformations on top of what > is required for single-threaded execution: introducing a store to a

On Mon, Aug 22, 2011 at 4:20 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 6:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >>> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>>> On

On Sun, Jul 31, 2011 at 7:11 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Sun, Jul 31, 2011 at 3:04 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> The current memory model section ends with the following discussions: >> >> "Note that in cases where none of the atomic intrinsics are used, this >> model places only one restriction on

On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: > On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >> <santosh.nagarakatte at gmail.com> wrote: >>> Hi all, >>> >>> I have been trying to understand the use of undef in

On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte > <santosh.nagarakatte at gmail.com> wrote: >> Hi all, >> >> I have been trying to understand the use of undef in both sequential >> and concurrent programs. >> >> >From the LLVM Language Reference Manual, I

> Hi all, > > Chandler, Owen, and I have written up a proposal for a new memory > model and atomic intrinsics in LLVM, which will make it possible to > support Java and the upcoming C++0x standard. The proposed changes to > the LangRef are at > <http://docs.google.com/View?docID=ddb4mhxz_22dz5g98dd&revision=_latest > >, > and a rationale for some of the more

On Mon, Aug 22, 2011 at 3:49 PM, Eli Friedman <eli.friedman at gmail.com> wrote: > On Mon, Aug 22, 2011 at 3:40 PM, Jianzhou Zhao <jianzhou at seas.upenn.edu> wrote: >> On Mon, Aug 22, 2011 at 6:08 PM, Eli Friedman <eli.friedman at gmail.com> wrote: >>> On Mon, Aug 22, 2011 at 2:49 PM, Santosh Nagarakatte >>> <santosh.nagarakatte at gmail.com>

On Sunday 25 April 2010 21:26:47 Jeffrey Yasskin wrote: > Hi all, > > Chandler, Owen, and I have written up a proposal for a new memory > model and atomic intrinsics in LLVM, which will make it possible to > support Java and the upcoming C++0x standard. The proposed changes to > the LangRef are at >