当大量元素时，Vulkan Buffer WorkGroupID不返回实际值 [英] Vulkan Buffer WorkGroupID not returning actual value when large number of elements

问题描述

使用 pow（2，24）和 local_size_x = 64 创建一个缓冲区作为布局输入限定符返回 WorkGroupID = 262143 ，由于 pow（2,24）/ 64-1 都很好，它为零

Creating a buffer with pow(2, 24) and a local_size_x = 64 for the layout input qualifier will return WorkGroupID = 262143 which is all fine due to pow(2,24) / 64 - 1, it is zero indexed.

但是，如果我们将问题的全局维度/无元素/大小增加到 pow（2，25）假设 WorkGroupID 将无缘无故地返回值，它们与数学值不匹配。

However if we increase the global dimension / no elements / size of the problem to pow(2, 25) lets say WorkGroupID will return values without a reason, they do not match the math.

这里有一些设备认为我认为重要的限制：

Here are some limits that the device got that I think matter:

maxStorageBufferRange:          uint32_t = 4294967295
        maxComputeSharedMemorySize:     uint32_t = 32768
        maxComputeWorkGroupCount:       uint32_t[3] = 00000202898A8EC4
            maxComputeWorkGroupCount[0]:    uint32_t = 65535
            maxComputeWorkGroupCount[1]:    uint32_t = 65535
            maxComputeWorkGroupCount[2]:    uint32_t = 65535
        maxComputeWorkGroupInvocations: uint32_t = 1024
        maxComputeWorkGroupSize:        uint32_t[3] = 00000202898A8ED4
            maxComputeWorkGroupSize[0]:     uint32_t = 1024
            maxComputeWorkGroupSize[1]:     uint32_t = 1024
            maxComputeWorkGroupSize[2]:     uint32_t = 1024

我不会过多分配设备支持的元素。
因此，经过2天+ 16小时，我仍然不知道发生了什么...

I do not go overboard with allocating more elements that the device supports. So after 2 days + 16 hrs I still did not figure out whats going on...

WorkGroupSize ， WorkGroupID ， LocalInvocationID 和 GlobalInvocationID 表示相同的内容问题，当我达到否。的元素。难怪 GlobalInvocationID 会由于计算方式而出现相同的问题...

WorkGroupSize, WorkGroupID, LocalInvocationID and GlobalInvocationID presents the same problem when I reach a n no. of elements. It is no wonder that GlobalInvocationID presents the same problem due to how it is calculated...

#version 450
// Size of the Local Work-group is defined trough input layout qualifier
layout(local_size_x = 64, local_size_y = 1, local_size_z = 1) in;


layout(set = 0, binding = 0) buffer deviceBuffer
{
   uint x[];
};


void main() {
    uint i = gl_GlobalInvocationID.x;
    //uint i = gl_WorkGroupSize.x * gl_WorkGroupID.x * gl_LocalInvocationID.x;


    //x[i] += x[i];

// Total No. of Work Items (threads) in Global Dimension
//x[i] = gl_NumWorkGroups.x;

// Size of Work Dimension specified in Input Layout Qualifier
//x[i] = gl_WorkGroupSize.x;

// Is given by Global Dimension / Work Group Size
x[i] = gl_WorkGroupID.x;

//x[i] = gl_LocalInvocationID.x;

}

推荐答案

maxComputeWorkGroupCount[0]: uint32_t = 65535
maxComputeWorkGroupCount[1]: uint32_t = 65535
maxComputeWorkGroupCount[2]: uint32_t = 65535

vkCmdDispatch 的大小为x = pow（2，25 ），y = 1，z = 1

vkCmdDispatch have the size in x = pow(2, 25), y = 1, z = 1

根据您提供的信息 groupCountX = 2 ²⁵ = 33554432，但限制为 maxComputeWorkGroupCount [0] = 65535 = 2 ¹⁶ -1

Based on the info you provided groupCountX = 2²⁵ = 33554432, but the limit is maxComputeWorkGroupCount[0] = 65535 = 2¹⁶-1.

Vulkan规范 vkCmdDispatch的有效用法说：

The Vulkan specification Valid Usage for vkCmdDispatch says:

• groupCountX 必须小于或等于 VkPhysicalDeviceLimits :: maxComputeWorkGroupCount [0]

• groupCountX must be less than or equal to VkPhysicalDeviceLimits::maxComputeWorkGroupCount[0]

违反有效用法是未定义的行为。 不确定的行为是指从看起来一切正常的一切到您的PC陷入黑洞并破坏该太阳系的任何事物。出于所有意图和目的，违反有效用法是应用程序代码的逻辑错误。

Violating Valid Usage is undefined behavior. "Undefined behavior" means anything from "everything seemingly working fine" to "your PC colapses into a black hole and destroys this solar system". For all intents and purposes violating Valid Usage is a logical error of the application code.

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