similar to: [LLVMdev] no differnce in the execution time between seq. and parallel programs

Hi esraa, > i am using LLVM to execute two programs both of them was exactly > similar but the difference was the first one is a sequential program > has three functions. In the second program i am trying to execute it > by giving each function to thread (three thread work in parallel way) > ,but when i am trying to calculate the execution time i found the > execution time for

Duncan Sands <baldrick <at> free.fr> writes: > > Hi esraa, > > > i am using LLVM to execute two programs both of them was exactly > > similar but the difference was the first one is a sequential program > > has three functions. In the second program i am trying to execute it > > by giving each function to thread (three thread work in parallel way)

Duncan Sands <baldrick <at> free.fr> writes: > > > I would be happy if you give me an insight into what could have caused the > > difference. > > No idea. Maybe you forgot to turn optimizations on when compiling? Otherwise > you are going to have to send in your programs along with an explanation of how > you compiled them exactly (exact sequence of

Hi all please can any one help me to find the reason?? i am using LLVM to execute two programs both of them was exactly similar but the difference was the first one is a sequential program has three functions. In the second program i am trying to execute it by giving each function to thread (three thread work in parallel way) ,but when i am trying to calculate the execution time i found

> I would be happy if you give me an insight into what could have caused the > difference. No idea. Maybe you forgot to turn optimizations on when compiling? Otherwise you are going to have to send in your programs along with an explanation of how you compiled them exactly (exact sequence of commands) both for gcc and LLVM. Ciao, Duncan.

Hello all, Thanks for the comments. Attached is a new version with Tobias' and Sebastian's (final?) comments addressed. Any further comments are appreciated. Nadav suggested a request for comments in llvmdev before committing it. In order to describe the current idea of the parallel loop metadata, I think it's easiest to just copy-paste the documentation I wrote for this patch so

Hi tobi, >> 2. Allow the some generic parallelism information live out specific >> autopar framework, so these information can benefit more passes in >> llvm. For example, the X86 and PTX backend could use these information >> to perform target specific auto-vectorization. > > What other types of parallelism are you expecting? We currently support > thread level

On 9 March 2015 at 17:30, Tobias Grosser <tgrosser at inf.ethz.ch> wrote: > If my memories are right, one of the critical issues (besides > other engineering considerations) was that parallelism metadata in LLVM is > optional and can always be dropped. However, for > OpenMP it sometimes is incorrect to execute a loop sequential that has been > marked parallel in the source

On 01/06/2011 03:38 AM, ether zhhb wrote: > Hi, > > I just have a detail look at the code of Polly[1], it seems that Polly > start to support some basic auto-parallelization stuffs. This is true. However still work in progress. I hope we can soon show some interesting results. > I have some idea to improve the current auto-vectorization > and parallelization approach in

Hi, I just have a detail look at the code of Polly[1], it seems that Polly start to support some basic auto-parallelization stuffs. I have some idea to improve the current auto-vectorization and parallelization approach in Polly. The main idea is, we separate the transform passes and codegen passes for auto-parallelization and vectorization (Graphite[2] for gcc seems to taking similar approach

I'm part of a research group at MIT looking to create an extension of LLVM that inherently allows one to nicely code a parallel loop. Most parallel frameworks tend to take the body of a parallel loop and stick it inside of a function for the parallel runtime to call when appropriate. However, this makes optimizations significantly more difficult as most compiler optimizations tend to be

This is an RFC to add analyses and transformation passes into LLVM to optimize programs based on an abstract notion of a parallel region. == this is _not_ a proposal to add a new encoding of parallelism == We currently perform poorly when it comes to optimizations for parallel codes. In fact, parallelizing your loops might actually prevent various optimizations that would have been applied

Hi, I have two questions about llvm, and expect your reply very much. 1. Is there any plan of llvm to support Thread-Level Parallelism by using OpenMP, MPI, pthread or llvm-defined directives? If automatic parallelism exploring is very hard, what is the key problem? We can't get the precise data dependence information at compile-time? 2. Can I use the functions provided by llvm to

Dear all, This RFC proposes three new LLVM IR instructions to express high-level parallel constructs in a simple, low-level fashion. For this first stage we prepared two commits that add the proposed instructions and a pass to lower them to obtain sequential IR. Both patches have be uploaded for review [1, 2]. The latter patch is very simple and the former consists of almost only mechanical

Hello, Below is a proposal for a GSoC project that I would like to work on this year. Your input and feedback is much appreciated. Background: ========= My name is Kareem Ergawy and I currently work as part of the PIR project. PIR is an extension of the IR to support fork-join parallelism that is currently under review [1, 2, 3, 4]. Goals: ===== As a GSoC project, here I propose an

Hi, I have only the vaguest notions of what parallel programing, but I think I have a situation where it might be of use to me, or at least provide me with the opportunity to learn more about it. Before I invest in figuring out the nuts and bolts, can anyone confirm that this is a sane approach, or provide alternatives that I could pursue? I'm running stochastic simulations, with the actual

On Jan 29, 2013, at 12:51 AM, Tobias Grosser <tobias at grosser.es> wrote: > > # ignore assumed dependences. > for (i = 0; i < 4; i++) { > tmp1 = A[3i+1]; > tmp2 = A[3i+2]; > tmp3 = tmp1 + tmp2; > A[3i] = tmp3; > } > > Now I apply for whatever reason a partial reg2mem transformation. > > float tmp3[1]; > > # ignore assumed

> On Mar 8, 2017, at 11:50 AM, Hal Finkel <hfinkel at anl.gov> wrote: > > > On 03/08/2017 01:24 PM, Tian, Xinmin wrote: >> I assume the referring case is something like below, right? >> >> #pragma omp parallel num_threads(n) >> { >> #pragma omp critical >> { >> x = x + 1; >> } >> }

I assume the referring case is something like below, right? #pragma omp parallel num_threads(n) { #pragma omp critical { x = x + 1; } } If that is the case, the programmer is already writing the code that is not "serial equivalent". Our representation for parallelizer is %t = @llvm.region.entry()["omp.parallel"(),

On 01/29/2013 07:58 PM, Nadav Rotem wrote: > > On Jan 29, 2013, at 12:51 AM, Tobias Grosser <tobias at grosser.es > <mailto:tobias at grosser.es>> wrote: > >> >> # ignore assumed dependences. >> for (i = 0; i < 4; i++) { >> tmp1 = A[3i+1]; >> tmp2 = A[3i+2]; >> tmp3 = tmp1 + tmp2; >> A[3i] = tmp3; >> } >>