Same problem:
#!/usr/bin/env python
import pyopencl as cl
KERNEL = r"""
__kernel void test() {
printf("%s", "Hello world!\n");
}
"""
for platform in cl.get_platforms():
for device in platform.get_devices():
if cl.device_type.to_string(device.type) == 'GPU':
ctx = cl.Context([device])
queue = cl.CommandQueue(ctx)
prg = cl.Program(ctx, KERNEL).build()
prg.test(queue, (1,), None).wait()
On the first run (when the kernel is compiled), it works. On the second run
without kernel modifications, it segfaults.
Also,
printf("%s", "Hello world!\n");
prints the sting, while
printf("Hello world!\n");
prints nothing.
On CPU, it works fine with both notations.
Anyway, printf() is a non-standard opencl extension, and simply put, you
should not use it.
On 5 May 2015 at 23:47, CRV§ADER//KY <[email protected]> wrote:
> I suspect PyOpenCL is innocent. With your code I'm sometimes getting
> completely random results, sometimes a segfault in amdocl64.dll on Windows
> 7/64 bit, Python 3.3.2, PyOpenCL 2013.2, and the latest catalyst drivers.
> The culprit definitely looks to be printf(). Everything works fine if you
> comment it out.
> By the way, you would get the same result if you removed the buffer
> altogether and set the workgroup size to (1,).
> Looks to me like a bug in the catalyst drivers.
>
>
>
>
> On 5 May 2015 at 19:08, Antonio Beamud <[email protected]> wrote:
>
>> I've created this simple test
>>
>> #!/usr/bin/env python
>> #-*- coding: utf-8 -*-
>>
>> import pyopencl as cl
>> import numpy as np
>>
>> ELEMENTS = 257
>>
>> KERNEL = """
>> __kernel void test(__global const int *a,
>> const int asize
>> )
>> {
>> int agid = get_global_id(0);
>> if (agid==0)
>> for(int i=0; i < asize; i++)
>> printf("agid:%u, i:%i, asize:%u\\n", agid, i, asize);
>> }
>> """
>>
>> a = np.random.randint(-1595081346, 1595081346, ELEMENTS).astype(np.int32)
>>
>> for platform in cl.get_platforms():
>> for device in platform.get_devices():
>> if cl.device_type.to_string(device.type) == 'GPU':
>> ctx = cl.Context([device])
>> queue = cl.CommandQueue(ctx)
>> mf = cl.mem_flags
>> a_buf = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR,
>> hostbuf=a)
>> prg = cl.Program(ctx, KERNEL).build()
>> exec_evt = prg.test(queue, (ELEMENTS,), None, a_buf,
>> np.int32(a.size))
>> exec_evt.wait()
>>
>> The tail output is:
>>
>> agid:0, i:252, asize:257
>> agid:0, i:253, asize:257
>> agid:0, i:254, asize:257
>> agid:0, i:0, asize:4294374642
>>
>> I'm running pyopencl 2014.1, with an R7 260x.
>> Why cannot process the 255 value? (with the CPU works fine) Is a problem
>> with the work group size?
>>
>> Thanks
>>
>> _______________________________________________
>> PyOpenCL mailing list
>> [email protected]
>> http://lists.tiker.net/listinfo/pyopencl
>>
>>
>
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