[FFmpeg-cvslog] vulkan: remove pointless mutex locks
Lynne
git at videolan.org
Sun Dec 22 21:25:56 EET 2024
ffmpeg | branch: master | Lynne <dev at lynne.ee> | Wed Dec 18 14:58:33 2024 +0900| [157cd820adbbfcfd1870a6ce12d072dc0f623e9b] | committer: Lynne
vulkan: remove pointless mutex locks
This code was simply incorrect through and through. It did not
protect what actually has to be protected in a multi-threaded setup.
Perhaps it was used to silence threading errors?
Either way, remove it, and document the correct way to use execution
pools in a threaded environment.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=157cd820adbbfcfd1870a6ce12d072dc0f623e9b
---
libavutil/vulkan.c | 12 ------------
libavutil/vulkan.h | 2 ++
2 files changed, 2 insertions(+), 12 deletions(-)
diff --git a/libavutil/vulkan.c b/libavutil/vulkan.c
index dc30539115..55b039d5ef 100644
--- a/libavutil/vulkan.c
+++ b/libavutil/vulkan.c
@@ -251,7 +251,6 @@ void ff_vk_exec_pool_free(FFVulkanContext *s, FFVkExecPool *pool)
vk->WaitForFences(s->hwctx->act_dev, 1, &e->fence, VK_TRUE, UINT64_MAX);
vk->DestroyFence(s->hwctx->act_dev, e->fence, s->hwctx->alloc);
}
- pthread_mutex_destroy(&e->lock);
ff_vk_exec_discard_deps(s, e);
@@ -424,11 +423,6 @@ int ff_vk_exec_pool_init(FFVulkanContext *s, FFVkQueueFamilyCtx *qf,
.flags = VK_FENCE_CREATE_SIGNALED_BIT,
};
- /* Mutex */
- err = pthread_mutex_init(&e->lock, NULL);
- if (err != 0)
- return AVERROR(err);
-
/* Fence */
ret = vk->CreateFence(s->hwctx->act_dev, &fence_create, s->hwctx->alloc,
&e->fence);
@@ -498,10 +492,8 @@ FFVkExecContext *ff_vk_exec_get(FFVulkanContext *s, FFVkExecPool *pool)
void ff_vk_exec_wait(FFVulkanContext *s, FFVkExecContext *e)
{
FFVulkanFunctions *vk = &s->vkfn;
- pthread_mutex_lock(&e->lock);
vk->WaitForFences(s->hwctx->act_dev, 1, &e->fence, VK_TRUE, UINT64_MAX);
ff_vk_exec_discard_deps(s, e);
- pthread_mutex_unlock(&e->lock);
}
int ff_vk_exec_start(FFVulkanContext *s, FFVkExecContext *e)
@@ -517,11 +509,7 @@ int ff_vk_exec_start(FFVulkanContext *s, FFVkExecContext *e)
/* Wait for the fence to be signalled */
vk->WaitForFences(s->hwctx->act_dev, 1, &e->fence, VK_TRUE, UINT64_MAX);
-
- /* vkResetFences is defined as being host-synchronized */
- pthread_mutex_lock(&e->lock);
vk->ResetFences(s->hwctx->act_dev, 1, &e->fence);
- pthread_mutex_unlock(&e->lock);
/* Discard queue dependencies */
ff_vk_exec_discard_deps(s, e);
diff --git a/libavutil/vulkan.h b/libavutil/vulkan.h
index ef39f76675..0a166da9eb 100644
--- a/libavutil/vulkan.h
+++ b/libavutil/vulkan.h
@@ -400,6 +400,8 @@ int ff_vk_qf_init(FFVulkanContext *s, FFVkQueueFamilyCtx *qf,
/**
* Allocates/frees an execution pool.
+ * If used in a multi-threaded context, there must be at least as many contexts
+ * as there are threads.
* ff_vk_exec_pool_init_desc() MUST be called if ff_vk_exec_descriptor_set_add()
* has been called.
*/
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