Intel® Cilk™ Plus

why does cilk_spawn give me such bad performance?

I wrote a simple benchmark that takes fills two vectors with a sequence of randomly computed numbers. I'm comparing tbb, cilk, and std::async. The results I get are (milliseconds):

time cilk: 3725

time async: 2367

time tbb: 2397

time serial: 4610

 

I compiled with (icc 2016)

 

icc -std=c++14 -xHost -O3 -tbb -pthread benchmark.cpp

 

And I'm running on

 

uname -a

Cilkview Cilkscreen Centos 7

Issues with Cilktools.  I have compiled and installed gcc 4.9 and gcc 5.2 on Centos 7 and installed them.  The fib.c test code runs fine for both gcc's.  

 

However when I attempt to use the cilktools provided on: 

https://www.cilkplus.org/download

I get the following error:

./cilkview: error while loading shared libraries: libstdc++.so.6: wrong ELF class: ELFCLASS64

Cilkview Cilkscreen Centos 7

Issues with Cilktools.  I have compiled and installed gcc 4.9 and gcc 5.2 on Centos 7 and installed them.  The fib.c test code runs fine for both gcc's.  

 

However when I attempt to use the cilktools provided on: 

https://www.cilkplus.org/download

I get the following error:

./cilkview: error while loading shared libraries: libstdc++.so.6: wrong ELF class: ELFCLASS64

Problem in Cilkview and Cilkscreen 4225

Hello,

I am new in Cilk plus. I am facing problem in Cilkview and Cilkscreen 4225. Please help/ guide me ...

I am working on Ubuntu 14.04 LTS with GCC 4.9.2. I install Intel Cilk Plus SDK by synaptic manager.

=> libcilkrts5, libcilkrts5-dbg, libx32cilkrts5, libx32cilkrts5-dbg

I wrote the following code

/**********************/

#include <iostream>
#include <cilk/cilk.h>

using namespace std;

How is the user worker thread returned when returning from cilk runtime?

Hi

In the Binary Interface Specification, it says when the last user thread calls __cilkrts_leave_frame() with a __cilkrts_stack_frame which has CILK_FRAME_LAST set in the flags field, the runtime will suspend all of the worker threads it created."

I have a question about when the stack frame set as CILK_FRAME_LAST gets stolen by the system worker.

gcc 5.1 -mfpmath=387 Floating point exception

It appears that the compiler option -mfpmath=387 immediately causes floating point exceptions on Intel architecture processors in cilk_spawn routines compiled with gcc-5.1 cilk.  This seems to be a regression as gcc-4.9 with the cilk patches works fine.  Note that -mfpmath=sse works on 64-bit machines, however, this option is not available for 32-bit Intel machines.  As far as I can tell, most floating point code is affected.  Does anyone know of patches or workarounds for this, especially as this appears to be a show-stopper on 32-bit Intel.

Cilkplus port to Raspberry Pi 2B

I compiled the new release of gcc-5.1 with the Cilkplus parallel processing extensions and runtime library for ARMv7 architecture on the Raspberry Pi 2B single board computer.  Two changes were needed.

The first change corrects a typo in generic/cilk-abi-vla.c by changing the second to the last line of the file from

vla_internal_heap_free(t, full_size);

to

vla_internal_heap_free(p, full_size);

the second change was to generic/os-fence.c and ARM specific. Comment out the line

COMMON_SYSDEP void __cilkrts_fence(void); ///< MFENCE instruction

Iscriversi a Intel® Cilk™ Plus