clEnqueueMarkerWithWaitList用法 [英] clEnqueueMarkerWithWaitList usage

问题描述

我最近读了一本关于OpenCL和队列同步方法的书，但是我不了解使用clEnqueueMarkerWithWaitList和clWaitforEvents之间的区别.

I recently read a book about OpenCL and queue synchronizing methods, but I didn't understand difference between using clEnqueueMarkerWithWaitList and clWaitforEvents.

例如，在下面的示例中，kernel_2实例的执行取决于将两个缓冲区clmem_A和clmem_B写入设备.我不了解删除clEnqueueMarkerWithWaitList命令并将clwaitforEvents的参数更改为write_event时有什么区别.

For example, in the below example, The kernel_2 instance's execution is dependent on writing of two buffers clmem_A and clmem_B to the device. I don't understand what is the difference when we delete the clEnqueueMarkerWithWaitList command and change the argument of clwaitforEvents to write_event.

cl_event write_event[2];
clEnqueueWriteBuffer(queue, clmem_A, ***, &write_event[0] );
clEnqueueWriteBuffer(queue, clmem_B, ***, &write_event[1] );
clEnqueueMarkerWithWaitList (queue, 2, write_event, &marker); //deleting this command
clEnqueueNDRangeKernel(queue, kernel_1, *** );
clWaitForEvents(1, &marker);// and replace marker with write_event
clEnqueueNDRangeKernel(queue, kernel_2, *** );

我相信在两种情况下，kernel_2都将在写入设备后执行，并且如果队列混乱，kernel_1可以同时执行.

I believe in both cases the kernel_2 will execute after writing to device and kernel_1 could execute concurrently if the queue is out of order.

推荐答案

是的，那是等效的.

clEnqueueMarkerWithWaitList是OpenCL 1.2中的新功能，并且比clWaitForEvents具有更大的灵活性，因为您可以携带单个事件而不是它们的集合.

clEnqueueMarkerWithWaitList is new starting in OpenCL 1.2 and offers more flexibility than clWaitForEvents in that you can carry around a single event rather than a collection of them.

如果您为OpenCL 1.1编码(例如，由于NVIDIA落后于行业)，则不能使用clEnqueueMarkerWithWaitList.

If you code for OpenCL 1.1 (e.g., because of NVIDIA lagging the industry) you can't use clEnqueueMarkerWithWaitList.

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