practicevorti.blogg.se - Berkeley upc memory fence

Berkeley upc memory fence portable#
Berkeley upc memory fence code#

10 Presentations at workshops, conferences, and panels, poster sessions.

Assignment using 4 problems in 2 PGAS languages.

4 Tutorials: PSC, SIAM PP04, SC02/SC03, IPDPS03.

Participation in UPC bi-annual consortium meeting.

Specification of UPC memory model in progress.

Algorithms that are challenging in MPI.

Berkeley NAS CG has several versions, including simpler, fine-grained communication.

Berkeley NAS MG avoids most global barriers and relies on UPC relaxed memory model.

Experiments with vectorization on the X1.

Find optimal message size for pipelining.

Replacing small messages with larger ones.

Extended cycle detection to arrays with three different algorithms.

Berkeley upc memory fence code#

Understand when code motion is legal without changing views from other processors.Research on support for pinning-based networks such as Infiniband and Myrinet.FY04 Ports: Infiniband, UDP, Shmem, GM+threads, Elan-4.Previously existing ports: IBM LAPI, Myrinet GM, Quadrics Elan-3.New pthread version runs on SGI Altix, SMPs, clusters of SMPs.Runtime portability, interoperability.Cray T3e, Cray X1, IBM SP, NEC SX-6, Cluster X (Big Mac), SGI Altix 3000.Myrinet GM, Quadrics Elan, Mellanox Infiniband VAPI, IBM LAPI, Cray X1, SGI Altix, Cray/SGI SHMEM.x86, Itanium, Alpha, Sparc, PowerPC, PA-RISC.Linux, FreeBSD, Tru64, AIX, IRIX, HPUX, Solaris, MSWindows(cygwin), MacOSX, Unicos, SuperUX.Runs on most SMPs, clusters & supercomputers.Compileroptimizations for parallel languages.Runtime work for Partitioned Global Address Space (PGAS) languages in general.

Berkeley upc memory fence portable#

A portable compiler: for future machines too.Those are conflicting operations on different threads with no happens-before relation a data race.Overview of Berkeley UPC Kathy Yelick Christian Bell, Dan Bonachea, Wei Chen, Jason Duell, Paul Hargrove, Parry Husbands, Costin Iancu, Mike Welcome a=10 have all happened-before that particular cout< berkeley upc memory fence

#include įlag.store(true, std::memory_order_relaxed) Here's a different example that I think demonstrates correct usage better. That is, your usage of fences does not ensure that your assignments to a are visible to other threads or that the value you read from a is 'up to date.' This is because, although you seem to have the basic idea of where fences should be used, your code does not actually meet the exact requirements for those fences to "synchronize". Your usage does not actually ensure the things you mention in your comments. Ensure that this thread's view of a is up to dateĪtomic_thread_fence(std::memory_order_acquire) Ensure that changes to a to this point are visible to other threadsĪtomic_thread_fence(std::memory_order_release) Is my understanding correct? Or have I missed the point entirely? #include I realize that this program doesn't do anything useful, I just wanted to make sure that the usage of the fence functions did what I thought they did.īasically that the release ensures that any changes made in this thread before the fence are visible to other threads after the fence, and that in the second thread that any changes to the variables are visible in the thread immediately after the fence? I'm trying to understand memory fences in c++11, I know there are better ways to do this, atomic variables and so on, but wondered if this usage was correct.