| Flutter Impeller |

Classes | Public Member Functions | Static Public Member Functions | List of all members
impeller::CommandPoolRecyclerVK Class Referencefinal

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

`#include <command_pool_vk.h>`

Inheritance diagram for impeller::CommandPoolRecyclerVK:

## Classes
struct | RecycledData
| A unique command pool and zero or more recycled command buffers. More...

## Public Member Functions
void | DestroyThreadLocalPools ()
| Clean up resources held by all per-thread command pools associated with the context. More...
| CommandPoolRecyclerVK (const std::shared_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, std::vector< vk::UniqueCommandBuffer > &&buffers, bool should_trim=false)
| Returns a command pool to be reset on a background thread. More...
void | Dispose ()
| Clears this context's thread-local command pool. More...

## Static Public Member Functions
static int | GetGlobalPoolCount (const ContextVK &context)

## 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 103 of file command_pool_vk.h.

## Constructor & Destructor Documentation

## ◆ CommandPoolRecyclerVK()

impeller::CommandPoolRecyclerVK::CommandPoolRecyclerVK | ( | const std::shared_ptr< ContextVK > & | context | ) |
| explicit

Creates a recycler for the given |ContextVK|.

Parameters

  [in] | context | The context to create the recycler for.

Definition at line 178 of file command_pool_vk.cc.

180 : context_(context), context_hash_(context->GetHash()) {}

## Member Function Documentation

## ◆ DestroyThreadLocalPools()

void impeller::CommandPoolRecyclerVK::DestroyThreadLocalPools | ( |  | ) |

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

Definition at line 304 of file command_pool_vk.cc.

304 {
305 // Delete the context's entry in this thread's command pool map.
306 if (tls_command_pool_map.get()) {
307 tls_command_pool_map.get()->erase(context_hash_);
308 }
309
310 // Destroy all other thread-local CommandPoolVK instances associated with
311 // this context.
312 Lock all_pools_lock(g_all_pools_map_mutex);
313 auto found = g_all_pools_map.find(context_hash_);
314 if (found != g_all_pools_map.end()) {
315 for (auto& [thread_id, weak_pool] : found->second) {
316 auto pool = weak_pool.lock();
317 if (!pool) {
318 continue;
319 }
320 // Delete all objects held by this pool. The destroyed pool will still
321 // remain in its thread's TLS map until that thread exits.
322 pool->Destroy();
323 }
324 g_all_pools_map.erase(found);
325 }
326 }
impeller::g_all_pools_map_mutex
static Mutex g_all_pools_map_mutex
Definition: command_pool_vk.cc:172
impeller::tls_command_pool_map
static thread_local std::unique_ptr< CommandPoolMap > tls_command_pool_map
Definition: command_pool_vk.cc:168

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

## ◆ Dispose()

void impeller::CommandPoolRecyclerVK::Dispose | ( |  | ) |

Clears this context's thread-local command pool.

Definition at line 289 of file command_pool_vk.cc.

289 {
290 CommandPoolMap* pool_map = tls_command_pool_map.get();
291 if (pool_map) {
292 pool_map->erase(context_hash_);
293 }
294
295 {
296 Lock all_pools_lock(g_all_pools_map_mutex);
297 auto found = g_all_pools_map.find(context_hash_);
298 if (found != g_all_pools_map.end()) {
299 found->second.erase(std::this_thread::get_id());
300 }
301 }
302 }
impeller::CommandPoolMap
std::unordered_map< uint64_t, std::shared_ptr< CommandPoolVK > > CommandPoolMap
Definition: command_pool_vk.cc:158

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

## ◆ 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 191 of file command_pool_vk.cc.

191 {
192 auto const strong_context = context_.lock();
193 if (!strong_context) {
194 return nullptr;
195 }
196
197 // If there is a resource in used for this thread and context, return it.
198 if (!tls_command_pool_map.get()) {
199 tls_command_pool_map.reset(new CommandPoolMap());
200 }
201 CommandPoolMap& pool_map = *tls_command_pool_map.get();
202 auto const it = pool_map.find(context_hash_);
203 if (it != pool_map.end()) {
204 return it->second;
205 }
206
207 // Otherwise, create a new resource and return it.
208 auto data = Create();
209 if (!data || !data->pool) {
210 return nullptr;
211 }
212
213 auto const resource = std::make_shared<CommandPoolVK>(
214 std::move(data->pool), std::move(data->buffers), context_);
215 pool_map.emplace(context_hash_, resource);
216
217 {
218 Lock all_pools_lock(g_all_pools_map_mutex);
219 g_all_pools_map[context_hash_][std::this_thread::get_id()] = resource;
220 }
221
222 return resource;
223 }
data
std::shared_ptr< const fml::Mapping > data
Definition: texture_gles.cc:68

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

## ◆ GetGlobalPoolCount()

int impeller::CommandPoolRecyclerVK::GetGlobalPoolCount | ( | const ContextVK & | context | ) |
| static

Definition at line 184 of file command_pool_vk.cc.

184 {
185 Lock all_pools_lock(g_all_pools_map_mutex);
186 auto it = g_all_pools_map.find(context.GetHash());
187 return it != g_all_pools_map.end() ? it->second.size() : 0;
188 }

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

Referenced by impeller::testing::TEST().

## ◆ Reclaim()

void impeller::CommandPoolRecyclerVK::Reclaim | ( | vk::UniqueCommandPool && | pool,
|  | std::vector< vk::UniqueCommandBuffer > && | buffers,
|  | bool | should_trim = `false`
| ) |  |

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

Parameters

  [in] | pool | The pool to recycle.
  [in] | should_trim | whether to trim command pool memory before reseting.

Definition at line 265 of file command_pool_vk.cc.

268 {
269 // Reset the pool on a background thread.
270 auto strong_context = context_.lock();
271 if (!strong_context) {
272 return;
273 }
274 auto device = strong_context->GetDevice();
275 if (should_trim) {
276 buffers.clear();
277 device.resetCommandPool(pool.get(),
278 vk::CommandPoolResetFlagBits::eReleaseResources);
279 } else {
280 device.resetCommandPool(pool.get(), {});
281 }
282
283 // Move the pool to the recycled list.
284 Lock recycled_lock(recycled_mutex_);
285 recycled_.push_back(
286 RecycledData{.pool = std::move(pool), .buffers = std::move(buffers)});
287 }

References impeller::CommandPoolRecyclerVK::RecycledData::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