## C Specification

Possible values of the flags member of VkPipelineCreationFeedbackEXT are:

// Provided by VK_EXT_pipeline_creation_feedback
typedef enum VkPipelineCreationFeedbackFlagBitsEXT {
VK_PIPELINE_CREATION_FEEDBACK_VALID_BIT_EXT = 0x00000001,
VK_PIPELINE_CREATION_FEEDBACK_APPLICATION_PIPELINE_CACHE_HIT_BIT_EXT = 0x00000002,
VK_PIPELINE_CREATION_FEEDBACK_BASE_PIPELINE_ACCELERATION_BIT_EXT = 0x00000004,
} VkPipelineCreationFeedbackFlagBitsEXT;

## Description

• VK_PIPELINE_CREATION_FEEDBACK_VALID_BIT_EXT indicates that the feedback information is valid.

• VK_PIPELINE_CREATION_FEEDBACK_APPLICATION_PIPELINE_CACHE_HIT_BIT_EXT indicates that a readily usable pipeline or pipeline stage was found in the pipelineCache specified by the application in the pipeline creation command.

An implementation should set the VK_PIPELINE_CREATION_FEEDBACK_APPLICATION_PIPELINE_CACHE_HIT_BIT_EXT bit if it was able to avoid the large majority of pipeline or pipeline stage creation work by using the pipelineCache parameter of vkCreateGraphicsPipelines, vkCreateRayTracingPipelinesKHR, vkCreateRayTracingPipelinesNV, or vkCreateComputePipelines. When an implementation sets this bit for the entire pipeline, it may leave it unset for any stage.

 Note Implementations are encouraged to provide a meaningful signal to applications using this bit. The intention is to communicate to the application that the pipeline or pipeline stage was created "as fast as it gets" using the pipeline cache provided by the application. If an implementation uses an internal cache, it is discouraged from setting this bit as the feedback would be unactionable.
• VK_PIPELINE_CREATION_FEEDBACK_BASE_PIPELINE_ACCELERATION_BIT_EXT indicates that the base pipeline specified by the basePipelineHandle or basePipelineIndex member of the Vk*PipelineCreateInfo structure was used to accelerate the creation of the pipeline.

An implementation should set the VK_PIPELINE_CREATION_FEEDBACK_BASE_PIPELINE_ACCELERATION_BIT_EXT bit if it was able to avoid a significant amount of work by using the base pipeline.

 Note While "significant amount of work" is subjective, implementations are encouraged to provide a meaningful signal to applications using this bit. For example, a 1% reduction in duration may not warrant setting this bit, while a 50% reduction would.