Intel® Parallel Composer

Question on the Status of Cilk Plus Support in GCC Mainline

Hi,

I read from the GCC 4.9.0 release notes that http://gcc.gnu.org/gcc-4.9/changes.html

Support for Cilk Plus has been added and can be enabled with the -fcilkplus option. Cilk Plus is an extension to the C and C++ languages to support data and task parallelism. The present implementation follows ABI version 1.2; all features but _Cilk_for have been implemented.

Cilk view got error with program compiled by GCC 4.9.0

Hi,

Recently, I have been compiling my Cilk plus program with GCC 4.9.0. Then I ran Cilk view to measure its parallelism and got this error:

Cilkview: Generating scalability data

Cilkview Scalability Analyzer V2.0.0, Build 3229

C:Tool (or Pin) caused signal 11 at PC 0x7f9124cd1dd3

 

Interestingly, when I compiled the program with GCC 4.8.2 and ran it with Cilk view again, it ran fine. So does it only happen with GCC 4.9.0? My guess is that GCC 4.9.0 isn't stable enough or not compatible with Cilk view at this time.

Thanks, 

Question on reducers

In my search application there are globally variables defined outside any function that I would like to use the cilk reducers on.

Specifically I have code like this:

#include "search.h"

static int total_users = 0;
static int total_matches = 0;

These total_x variables are incremented throughout the application on different functions.

I tried adding the following for total_users and received the following error:

How to use the cilkview?

I have a C search application  on a centos 6.x 64 bit linux server that I just installed the cilkplus compiler on to take advantage of more cpu/cores. I've added the cilk_spawn function to some recursive scanning functions in my program.  After re-compiling the search application with the cilkplus gcc compiler, the search program is working as intended without any seg faults or any other errors.

My question is how do I use the cilkview analyzer? I want to if cilkplus/spawning is helping my search application and if so by how much?

Thanks!

Lawrence

 

 

developer documents for Cilk Plus

Hi,

First I would like to thank you all for the awesome cilk plus tools you have open source in GCC and LLVM.

I am trying to study the runtime library and finding it a bit difficult to follow the execution in a sample application.

Are there any developer documents available? A wiki perhaps.

Specifically, I am trying to trace the execution path for cilk_spawn which is a key word. Any helpful links to get me started would be really great!

Thanks,

Arya

Question about steal-continuation semantics in Cilk Plus, Global counter slowing down computation, return value of functions

1)
What I understood about steal-continuation is, that every idle thread does not actually steal work, but the continuation which generates a new working item.
Does that mean, that inter-spawn execution time is crucial? If 2 threads are idle at the same time, from what I understand only one can steal the continuation and create its working unit, the other thread stays idle during that time?!

2)
As a debugging artefact, I had a global counter incremented on every function call of a function used within every working item.

Assine o Intel® Parallel Composer