# Linux Vulkan driver issue with timeline semaphors

**URL:** <https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972>\
**Category:** Linux\
**Tags:** linux-driver, vulkan, linux\
**Created:** [April 17, 2024, 7:41pm UTC](https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972 "2024-04-17T19:41:49Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![zbendefy](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@zbendefy](https://forums.developer.nvidia.com/u/zbendefy)\
**Post date:** [April 17, 2024, 7:41pm UTC](https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972/1 "2024-04-17T19:41:49Z")

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Hi!

I’m investigating a curious issue on linux, when using Vulkan timeline semaphors.

At one point of our pipeline, we have a large number of the following workflow:

for 1 to 40:  
CommandRecord();  
Submit(waitForTimeline: i, signal: i+1) //This submits the commands, and signals i+1 once it finishes  
vkWaitSemaphors(waitForTimeline: i+1, timeout=UINT64\_MAX); // This line waits on the CPU for the GPU commands to finish

(There are multiple threads doing the similiar things, but the timeline index is properly synchronizedacross threads)

Now the GPU workload usually runs for ~200 microseconds, however in some seemingly random cases it takes almost exactly 10 milliseconds.

In Nsight, I can see that the 10 milliseconds consists of a 200microseconds of GPU work, but after that there is absolutely no workload neither on the GPU, and the CPU.

The interesting thing is, that if I replace the vkWaitSemaphors() with the following, logically equivalent solution, then this 10ms bubble completely disappears, and performance is good again:

while(vkWaitSemaphors(waitForTimeline: i+1, timeout=5000) == VK\_TIMEOUT) {}

This does a busy wait polling on the timeline semaphor, and for some reason it works fine.

The driver I use is: 535.171.04, but i have reports of this on the latest drivers as well  
This issue is not present on windows.

Here is an image from NSight with the 10ms of no workload:

 ![image](https://global.discourse-cdn.com/nvidia/original/4X/d/1/8/d18e7d8117fbc97ecf7f2126e88955f81d0ad558.jpeg)

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<div class="post-metadata">

**Author:** ![zbendefy](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@zbendefy](https://forums.developer.nvidia.com/u/zbendefy)\
**Post date:** [May 10, 2024, 7:54am UTC](https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972/2 "2024-05-10T07:54:10Z")

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Bump,

For now this workaround seems to work, but it would be good to realy on the driver’s function instead of the busy wait :)

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**Author:** ![zoltan.bendefy](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@zoltan.bendefy](https://forums.developer.nvidia.com/u/zoltan.bendefy)\
**Post date:** [June 3, 2024, 12:58pm UTC](https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972/3 "2024-06-03T12:58:20Z")

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Bump.

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**Author:** ![zoltan.bendefy](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@zoltan.bendefy](https://forums.developer.nvidia.com/u/zoltan.bendefy)\
**Post date:** [June 2, 2026, 2:36pm UTC](https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972/4 "2026-06-02T14:36:05Z")

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Any updates on this? I could still reproduce this on recent drivers.

Is there any information that could help resolving this?

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**Author:** ![vanditd](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/vanditd/32/382649_2.png) [@vanditd](https://forums.developer.nvidia.com/u/vanditd)\
**Post date:** [September 21, 2026, 6:12am UTC](https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972/5 "2026-09-21T06:12:35Z")

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Hi @zoltan.bendefy, I think it is fixed on r580 and newer drivers via internal tracking Bug 6002233.  
Could you let me know which recent driver version are you using?

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<div class="post-metadata">

**Author:** ![zoltan.bendefy](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@zoltan.bendefy](https://forums.developer.nvidia.com/u/zoltan.bendefy)\
**Post date:** [September 21, 2026, 7:03am UTC](https://forums.developer.nvidia.com/t/linux-vulkan-driver-issue-with-timeline-semaphors/289972/6 "2026-09-21T07:03:55Z")

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Thank you for reporting back! I’m not sure on which exact version I reproduced it, but I’ll try again with 580 or newer and see if its resolved!