From 16df6fe33d3eecf72a6992b10fb0a6e5b3461d85 Mon Sep 17 00:00:00 2001 From: Mahmoud Mazouz Date: Mon, 16 Dec 2024 12:22:58 +0100 Subject: [PATCH] Recycle serialization buffers on transmission. Adds a LIFO buffer pool in the context to reuse buffers allocated on serialization. The aim is not (only) to avoid the overhead of dynamic allocation but rather to enhance the cache locality of serialization buffers. --- rmw_zenoh_cpp/src/detail/buffer_pool.hpp | 86 +++++++++++++++++++ .../src/detail/rmw_context_impl_s.hpp | 4 + .../src/detail/rmw_publisher_data.cpp | 27 +++--- 3 files changed, 104 insertions(+), 13 deletions(-) create mode 100644 rmw_zenoh_cpp/src/detail/buffer_pool.hpp diff --git a/rmw_zenoh_cpp/src/detail/buffer_pool.hpp b/rmw_zenoh_cpp/src/detail/buffer_pool.hpp new file mode 100644 index 00000000..ce45f71a --- /dev/null +++ b/rmw_zenoh_cpp/src/detail/buffer_pool.hpp @@ -0,0 +1,86 @@ +// Copyright 2024 Open Source Robotics Foundation, Inc. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef DETAIL__BUFFER_POOL_HPP_ +#define DETAIL__BUFFER_POOL_HPP_ + +#include +#include +#include + +#include "rcutils/allocator.h" + +class BufferPool +{ +public: + BufferPool() = default; + + uint8_t * allocate(rcutils_allocator_t *allocator, size_t size) + { + // FIXME(fuzzypixelz): indeed, this methods leaks all allocated buffers ;) + std::lock_guard guard(mutex_); + + if (available_buffers_.empty()) { + uint8_t * data = static_cast(allocator->allocate(size, allocator->state)); + if (data == nullptr) { + return nullptr; + } + Buffer buffer; + buffer.data = data; + buffer.size = size; + buffers_.push_back(buffer); + return data; + } else { + size_t available_buffer = available_buffers_.back(); + Buffer & buffer = buffers_.at(available_buffer); + if (buffer.size < size) { + uint8_t * data = static_cast(allocator->reallocate( + buffer.data, size, allocator->state)); + if (data == nullptr) { + return nullptr; + } + buffer.data = data; + buffer.size = size; + } + available_buffers_.pop_back(); + return buffer.data; + } + } + + void + deallocate(uint8_t *data) + { + std::lock_guard guard(mutex_); + + for (size_t i = 0; i < buffers_.size(); i++) { + if (buffers_.at(i).data == data) { + available_buffers_.push_back(i); + return; + } + } + } + +private: + struct Buffer + { + uint8_t *data; + size_t size; + }; + + std::vector buffers_; + std::vector available_buffers_; + std::mutex mutex_; +}; + +#endif // DETAIL__BUFFER_POOL_HPP_ diff --git a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp index ee30b3e0..1d444915 100644 --- a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp +++ b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp @@ -24,6 +24,7 @@ #include "graph_cache.hpp" #include "rmw_node_data.hpp" +#include "buffer_pool.hpp" #include "rmw/ret_types.h" #include "rmw/types.h" @@ -92,6 +93,9 @@ struct rmw_context_impl_s final // Forward declaration class Data; + // Pool of serialization buffers. + BufferPool serialization_buffer_pool; + private: std::shared_ptr data_{nullptr}; }; diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp index f54c50ab..625e5905 100644 --- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp +++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp @@ -227,6 +227,12 @@ PublisherData::PublisherData( events_mgr_ = std::make_shared(); } +void delete_z_bytes(void *data, void *context) +{ + BufferPool *pool = reinterpret_cast(context); + pool->deallocate(static_cast(data)); +} + ///============================================================================= rmw_ret_t PublisherData::publish( const void * ros_message, @@ -244,7 +250,7 @@ rmw_ret_t PublisherData::publish( type_support_impl_); // To store serialized message byte array. - char * msg_bytes = nullptr; + uint8_t * msg_bytes = nullptr; std::optional shmbuf = std::nullopt; auto always_free_shmbuf = rcpputils::make_scope_exit( [&shmbuf]() { @@ -254,13 +260,7 @@ rmw_ret_t PublisherData::publish( }); rcutils_allocator_t * allocator = &rmw_node_->context->options.allocator; - - auto always_free_msg_bytes = rcpputils::make_scope_exit( - [&msg_bytes, allocator, &shmbuf]() { - if (msg_bytes && !shmbuf.has_value()) { - allocator->deallocate(msg_bytes, allocator->state); - } - }); + rmw_context_impl_s * context_impl = static_cast(rmw_node_->data); // Get memory from SHM buffer if available. if (shm_provider.has_value()) { @@ -274,21 +274,21 @@ rmw_ret_t PublisherData::publish( if (alloc.status == ZC_BUF_LAYOUT_ALLOC_STATUS_OK) { shmbuf = std::make_optional(alloc.buf); - msg_bytes = reinterpret_cast(z_shm_mut_data_mut(z_loan_mut(alloc.buf))); + msg_bytes = reinterpret_cast(z_shm_mut_data_mut(z_loan_mut(alloc.buf))); } else { // TODO(Yadunund): Should we revert to regular allocation and not return an error? RMW_SET_ERROR_MSG("Failed to allocate a SHM buffer, even after GCing."); return RMW_RET_ERROR; } } else { - // Get memory from the allocator. - msg_bytes = static_cast(allocator->allocate(max_data_length, allocator->state)); + // Get memory from the buffer pool. + msg_bytes = context_impl->serialization_buffer_pool.allocate(allocator, max_data_length); RMW_CHECK_FOR_NULL_WITH_MSG( msg_bytes, "bytes for message is null", return RMW_RET_BAD_ALLOC); } // Object that manages the raw buffer - eprosima::fastcdr::FastBuffer fastbuffer(msg_bytes, max_data_length); + eprosima::fastcdr::FastBuffer fastbuffer(reinterpret_cast(msg_bytes), max_data_length); // Object that serializes the data rmw_zenoh_cpp::Cdr ser(fastbuffer); @@ -318,7 +318,8 @@ rmw_ret_t PublisherData::publish( if (shmbuf.has_value()) { z_bytes_from_shm_mut(&payload, z_move(shmbuf.value())); } else { - z_bytes_copy_from_buf(&payload, reinterpret_cast(msg_bytes), data_length); + z_bytes_from_buf(&payload, msg_bytes, data_length, delete_z_bytes, + reinterpret_cast(&context_impl->serialization_buffer_pool)); } z_result_t res = z_publisher_put(z_loan(pub_), z_move(payload), &options);