search for: parallelizer

qemu-io 2.12 will be changing its default alignment to unknown servers so that it does read-modify-write for anything less than 512 bytes. If we implement NBD_OPT_GO, then we can keep qemu-io using 1-byte alignment; but until then, this breaks our parallel tests when using 1-byte alignment because they end up with more delays than expected (thanks to the read-modify-write). Revamp the tests to

Hello, I'd like to see support in clang/LLVM for multi-core parallelism, especially support for OpenMP. I think that the best way to do this is by designing an LLVM-based API (metadata and intrinsics) for expressing parallelism constructs, and having clang lower OpenMP code to that API. This will allow maximal preservation of optimization capabilities including target-specific lowering. What

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

If nbdkit has a bug (such as the nbd-standalone bug fixed in the previous commit), qemu-io ends up waiting forever rather than realizing that if the server disappears unexpectedly then qemu-io should quit. So add timeouts so the testsuite will flag the problem instead of hang (tested by reordering this commit before the previous). It's trickier than I expected: from the command line,

Hal, Andrey, Alexey, >From the LLVM design viewpoint, there is a fundamental problem with both Hal's approach and the Intel approach: both are quite language-specific. OpenMP is a particular parallel language, with particular constructs (e.g., parallel regions) and semantics. LLVM is a language-neutral IR and infrastructure and OpenMP-specific concepts should not creep into it. I've

<mehdi.amini at apple.com>, Bcc: Subject: Re: [llvm-dev] [RFC][PIR] Parallel LLVM IR -- Stage 0 -- IR extension Reply-To: In-Reply-To: <20170224221713.GA931 at arch-linux-jd.home> Ping. PS. Are there actually people interested in this? We will continue working anyway but it might not make sense to put it on reviews and announce it on the ML if nobody cares. On 02/24,

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

...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"(), "num_threads"(int32 %n)] { __kmpc_critical() x = x + 1; __kmpc_end_critical() } @llvm.region.exit()["end.omp.parallel"()] Xinmin -----Original Message----- From: Hal Finkel [mailto:hfi...

A quick update, we have been looking through all LLVM passes to identify the impact of "IR-region annotation", and interaction issues with the rest of LoopOpt and scalarOpt, e.g. interaction with vectorization when you have schedule(simd:guided: 64). What are the common properties for optimizer to know on IR-region annotations. We have our implementation working from O0, O1, O2 to O3.

".... the problem Mehdi pointed out regarding the missed initializations of array elements, did you comment on that one yet?" What is the initializations of array elements question? I don't remember this question. Please refresh my memory. Thanks. I thought Mehdi's question is more about what are attributes needed for these IR-annotation for other LLVM pass to understand and

Hi, On 08/10/2012 11:06 PM, Hal Finkel wrote: > I'd like to see support in clang/LLVM for multi-core parallelism, > especially support for OpenMP. I think that the best way to do this is > by designing an LLVM-based API (metadata and intrinsics) for > expressing parallelism constructs, and having clang lower OpenMP code > to that API. This will allow maximal preservation

On Feb 7, 2013, at 10:55 AM, Pekka Jääskeläinen <pekka.jaaskelainen at tut.fi> wrote: > Hi Nadav, > > On 02/07/2013 07:46 PM, Nadav Rotem wrote: >> Pekka suggested that we add two kind of metadata: llvm.loop.parallel >> (attached to each loop latch) and llvm.mem.parallel (attached to each memory >> instruction!). I think that the motivation for the first

Dear all, Here's an updated version of the parallel loop metadata patch. It includes documentation for the new metadata types with a semantics description. -- Pekka -------------- next part -------------- A non-text attachment was scrubbed... Name: parallel-loop-metadata.patch Type: text/x-patch Size: 12972 bytes Desc: not available URL:

...eads(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"(), "num_threads"(int32 %n)] >> { >> __kmpc_critical() >> x = x + 1; >> __kmpc_end_critical() >> } >> @llvm.region.exit()["end.omp.parallel&quot...

The IR-region annotation we proposed is as below, there is no @llvm.parallel.for.iterator()..... There is no change to loop CFG. alloc A[100]; %t = call token @llvm.region.entry()["parallel.for"()] for(i = 0; i < 100; i++) { a[i] = f(i); } @llvm.region.exit(%t)() ["end.parallel.for"()] Xinmin -----Original Message----- From: Johannes Doerfert

On 03/08/2017 12:44 PM, Johannes Doerfert wrote: > I don't know who pointed it out first but Mehdi made me aware of it at > CGO. I try to explain it shortly. > > Given the following situation (in pseudo code): > > alloc A[100]; > parallel_for(i = 0; i < 100; i++) > A[i] = f(i); > > acc = 1; > for(i = 0; i < 100; i++) > acc = acc *

On Wed, Jan 30, 2013 at 12:35 PM, Pekka Jääskeläinen <pekka.jaaskelainen at tut.fi> wrote: > Thank you all for comments, > > > On 01/30/2013 11:22 AM, David Tweed wrote: >> >> In a personal capacity I'm quite interested in the issues of producing >> from a >> high-level language some LLVM IR which is labelled with vectorization info >> (including

> On Mar 8, 2017, at 10:55 AM, Mehdi Amini <mehdi.amini at apple.com> wrote: > >> >> On Mar 8, 2017, at 5:36 AM, Johannes Doerfert <doerfert at cs.uni-saarland.de> wrote: >> >> <mehdi.amini at apple.com>, >> Bcc: >> Subject: Re: [llvm-dev] [RFC][PIR] Parallel LLVM IR -- Stage 0 -- IR extension >> Reply-To: >>

This is for consistency with qemu-img, socat, ss, etc where we test for these binaries at run time. --- configure.ac | 4 ---- tests/Makefile.am | 8 +++----- tests/test-parallel-file.sh | 20 +++++++++++++------- tests/test-parallel-nbd.sh | 20 +++++++++++++------- 4 files changed, 29 insertions(+), 23 deletions(-) diff --git a/configure.ac b/configure.ac index

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