Hi Bernd,
We have some testcases, but they require XeonPhi hardware and a
working libgomp plugin. Our current version of the plugin depends on
some libraries, that are not open-sourced yet, so currently we can’t
share it.
However, you could examine what these patches do, making the following steps:
1) Build GCC with patches:
http://gcc.gnu.org/ml/gcc-patches/2013-12/msg01484.html
http://gcc.gnu.org/ml/gcc-patches/2013-12/msg01485.html
http://gcc.gnu.org/ml/gcc-patches/2013-12/msg01486.html
http://gcc.gnu.org/ml/gcc-patches/2013-12/msg01896.html
2) Set environment variables (e.g. for two ‘targets’):
export OFFLOAD_TARGET_NAMES=mic:hsail (for now
names don’t really matter)
export OFFLOAD_TARGET_COMPILERS=./gcc:./gcc (use GCC with
patches above as target compiler, because it must support the
-fopenmp_target option)
3) Build any example with #pragma omp target (e.g. see attachment):
./gcc -flto -fopenmp test.c -o test.exe
Options -flto and -fopenmp are necessary for using.
Now you have a binary with target images embedded and tables properly
filled. You can’t run it due to reasons mentioned above, though you
could examine it with objdump/nm/readelf to see new sections and their
content: there will be .offload_image_section with ‘target’ code and
.offload_func_table_section with ‘target’ function table.
On Tue, Jan 21, 2014 at 6:40 PM, Bernd Schmidt <ber...@codesourcery.com> wrote:
> On 12/17/2013 12:35 PM, Michael V. Zolotukhin wrote:
>>
>> Here is a set of patches implementing one more piece of offloading support
>> in
>> GCC. These three patches allow to build a host binary with target image
>> and all
>> tables embedded. Along with patches for libgomp and libgomp plugin, which
>> hopefully will be sent soon, that gives a functional and runnable
>> executable (or
>> DSO) with actual offloading to MIC.
>
>
> Do you have a testcase that can be used to see what this does in action?
>
>
> Bernd
>
--
Best regards,
Andrey Turetskiy
#define NUM 128
#pragma omp declare target
int cnt = 100;
int calc (int x)
{
return cnt++ * x;
}
#pragma omp end declare target
int main ()
{
int a[NUM];
int i;
cnt = 0;
#pragma omp target update to(cnt)
a[0] = 1;
for (i = 1; i < NUM; i++)
a[i] = -a[i-1];
#pragma omp target data map(to: a)
{
for (i = 0; i < NUM; i++)
a[i] = 2*a[i];
#pragma omp target
{
for (i = 0; i < NUM; i++)
a[i] = calc (a[i]);
}
#pragma omp target update from(a)
}
return 0;
}
