Bug 105292

Summary: vkGetQueryPoolResults returns incorrect query status for large query buffers (bisected)
Product: Mesa Reporter: Philip Rebohle <philip.rebohle>
Component: Drivers/Vulkan/radeonAssignee: mesa-dev
Status: RESOLVED FIXED QA Contact: mesa-dev
Severity: normal    
Priority: medium    
Version: git   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments: Modification to the 'occlusionquery' demo to reproduce the issue
workaround

Description Philip Rebohle 2018-02-28 14:47:25 UTC 
Created attachment 137687 [details] [review]
Modification to the 'occlusionquery' demo to reproduce the issue

Under certain circumstances, vkGetQueryPoolResults will always return VK_NOT_READY for a query pool, even when all of the requested queries should be available. When using VK_QUERY_RESULT_WAIT_BIT, the function never returns.

The attached patch is a modification to Sascha Willems' 'occlusionquery' demo which triggers the issue. Tested on an RX 480, mesa-git as of d448954228e69fd1b4000ea13e28c2ba2832db13, with validation layers enabled.

The following conditions have to be met in order to trigger this issue:
- The query pool has to be fairly large (>= 32 queries)
- vkCmdBeginQuery has to be called shortly or immediately after vkCmdResetQueryPool, outside a render pass instance.

This issue was introduced with the following commit:
[a41e2e9cf5f865f21e32cac2ed2e25dd21a05119] radv: allow to use a compute shader for resetting the query pool
Comment 1 Samuel Pitoiset 2018-02-28 15:56:54 UTC 
Yeah, I think it's because we don't emit the cache flushes after resetting the query pool with a compute shader.
Comment 2 Samuel Pitoiset 2018-02-28 16:00:49 UTC 
Created attachment 137690 [details] [review]
workaround

This fixes the issue for me, but I will probably come with a better solution a bit later.
Comment 3 Samuel Pitoiset 2018-02-28 17:00:35 UTC 
Here's the fix https://patchwork.freedesktop.org/patch/207416/

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