impeller::CommandPoolRecyclerVK Class Reference

Creates and manages the lifecycle of |vk::CommandPool| objects. More...

#include <command_pool_vk.h>

Inheritance diagram for impeller::CommandPoolRecyclerVK:

Public Member Functions
	~CommandPoolRecyclerVK ()
	CommandPoolRecyclerVK (std::weak_ptr< ContextVK > context)
	Creates a recycler for the given |ContextVK|. More...
std::shared_ptr< CommandPoolVK >	Get ()
	Gets a command pool for the current thread. More...
void	Reclaim (vk::UniqueCommandPool &&pool)
	Returns a command pool to be reset on a background thread. More...
void	Dispose ()
	Clears all recycled command pools to let them be reclaimed. More...

Static Public Member Functions
static void	DestroyThreadLocalPools (const ContextVK *context)
	Clean up resources held by all per-thread command pools associated with the given context. More...

Detailed Description

Creates and manages the lifecycle of |vk::CommandPool| objects.

A |vk::CommandPool| is expensive to create and reset. This class manages the lifecycle of |vk::CommandPool| objects by creating and recycling them; or in other words, a pool for command pools.

A single instance should be created per |ContextVK|.

Every "frame", a single |CommandPoolResourceVk| is made available for each thread that calls |Get|. After calling |Dispose|, the current thread's pool is moved to a background thread, reset, and made available for the next time |Get| is called and needs to create a command pool.

Commands in the command pool are not necessarily done executing when the pool is recycled, when all references are dropped to the pool, they are reset and returned to the pool of available pools.

Note

This class is thread-safe.

See also

|vk::CommandPoolResourceVk|

|ContextVK|

https://arm-software.github.io/vulkan_best_practice_for_mobile_developers/samples/performance/command_buffer_usage/command_buffer_usage_tutorial.html

Definition at line 95 of file command_pool_vk.h.

Constructor & Destructor Documentation

~CommandPoolRecyclerVK()

impeller::CommandPoolRecyclerVK::~CommandPoolRecyclerVK

(

)

Definition at line 232 of file command_pool_vk.cc.

                                              {
  // Ensure all recycled pools are reclaimed before this is destroyed.
  Dispose();
}

References Dispose().

CommandPoolRecyclerVK()

impeller::CommandPoolRecyclerVK::CommandPoolRecyclerVK ( std::weak_ptr< ContextVK >  context )

inlineexplicit

Creates a recycler for the given |ContextVK|.

Parameters

[in]

context

The context to create the recycler for.

Definition at line 109 of file command_pool_vk.h.

      : context_(std::move(context)) {}

Member Function Documentation

DestroyThreadLocalPools()

void impeller::CommandPoolRecyclerVK::DestroyThreadLocalPools ( const ContextVK *  context )

static

Clean up resources held by all per-thread command pools associated with the given context.

Parameters

[in]

context

The context.

Definition at line 244 of file command_pool_vk.cc.

                                                                            {
  // Delete the context's entry in this thread's command pool map.
  if (tls_command_pool_map.get()) {
    tls_command_pool_map.get()->erase(context->GetHash());
  }
 
  // Destroy all other thread-local CommandPoolVK instances associated with
  // this context.
  Lock all_pools_lock(g_all_pools_map_mutex);
  auto found = g_all_pools_map.find(context);
  if (found != g_all_pools_map.end()) {
    for (auto& weak_pool : found->second) {
      auto pool = weak_pool.lock();
      if (!pool) {
        continue;
      }
      // Delete all objects held by this pool.  The destroyed pool will still
      // remain in its thread's TLS map until that thread exits.
      pool->Destroy();
    }
    g_all_pools_map.erase(found);
  }
}

References impeller::g_all_pools_map_mutex, impeller::ContextVK::GetHash(), and impeller::tls_command_pool_map.

Referenced by impeller::ContextVK::~ContextVK().

Dispose()

void impeller::CommandPoolRecyclerVK::Dispose

(

)

Clears all recycled command pools to let them be reclaimed.

Definition at line 237 of file command_pool_vk.cc.

                                    {
  CommandPoolMap* pool_map = tls_command_pool_map.get();
  if (pool_map) {
    pool_map->clear();
  }
}

References impeller::tls_command_pool_map.

Referenced by ~CommandPoolRecyclerVK().

Get()

std::shared_ptr< CommandPoolVK > impeller::CommandPoolRecyclerVK::Get

(

)

Gets a command pool for the current thread.

Warning

Returns a |nullptr| if a pool could not be created.

Definition at line 144 of file command_pool_vk.cc.

                                                        {
  auto const strong_context = context_.lock();
  if (!strong_context) {
    return nullptr;
  }
 
  // If there is a resource in used for this thread and context, return it.
  if (!tls_command_pool_map.get()) {
    tls_command_pool_map.reset(new CommandPoolMap());
  }
  CommandPoolMap& pool_map = *tls_command_pool_map.get();
  auto const hash = strong_context->GetHash();
  auto const it = pool_map.find(hash);
  if (it != pool_map.end()) {
    return it->second;
  }
 
  // Otherwise, create a new resource and return it.
  auto pool = Create();
  if (!pool) {
    return nullptr;
  }
 
  auto const resource =
      std::make_shared<CommandPoolVK>(std::move(*pool), context_);
  pool_map.emplace(hash, resource);
 
  {
    Lock all_pools_lock(g_all_pools_map_mutex);
    g_all_pools_map[strong_context.get()].push_back(resource);
  }
 
  return resource;
}

References impeller::g_all_pools_map_mutex, and impeller::tls_command_pool_map.

Reclaim()

void impeller::CommandPoolRecyclerVK::Reclaim

(

vk::UniqueCommandPool &&

pool

)

Returns a command pool to be reset on a background thread.

Parameters

[in]

pool

The pool to recycler.

Definition at line 216 of file command_pool_vk.cc.

                                                              {
  TRACE_EVENT0("impeller", "ReclaimCommandPool");
 
  // Reset the pool on a background thread.
  auto strong_context = context_.lock();
  if (!strong_context) {
    return;
  }
  auto device = strong_context->GetDevice();
  device.resetCommandPool(pool.get());
 
  // Move the pool to the recycled list.
  Lock recycled_lock(recycled_mutex_);
  recycled_.push_back(std::move(pool));
}

---

The documentation for this class was generated from the following files:

• impeller/renderer/backend/vulkan/command_pool_vk.h
• impeller/renderer/backend/vulkan/command_pool_vk.cc