Improve max_allocations calculation on SHM transport (#5659)

* Refs #22841. Improve max_allocations calculation.

Signed-off-by: Miguel Company <[email protected]>

* Refs #22841. Consider a mean message size of half the max message size.

Signed-off-by: Miguel Company <[email protected]>

* Refs #22841. Move `shm_default_segment_size` to global scope.

Signed-off-by: Miguel Company <[email protected]>

* Refs #22841. Move `SharedMemTransportDescriptor` constants.

Signed-off-by: Miguel Company <[email protected]>

* Refs #22841. Change calculation of `mean_message_size`.

Signed-off-by: Miguel Company <[email protected]>

---------

Signed-off-by: Miguel Company <[email protected]>

Author: MiguelCompany

include/fastdds/rtps/transport/shared_mem/SharedMemTransportDescriptor.hpp

@@ -20,6 +20,7 @@
 #ifndef FASTDDS_RTPS_TRANSPORT_SHARED_MEM__SHAREDMEMTRANSPORTDESCRIPTOR_HPP
 #define FASTDDS_RTPS_TRANSPORT_SHARED_MEM__SHAREDMEMTRANSPORTDESCRIPTOR_HPP
 
+#include <cstdint>
 #include <string>
 
 #include <fastdds/rtps/attributes/ThreadSettings.hpp>
@@ -48,6 +49,10 @@ class TransportInterface;
  */
 struct SharedMemTransportDescriptor : public PortBasedTransportDescriptor
 {
+    static constexpr uint32_t shm_default_segment_size = 0;
+    static constexpr uint32_t shm_default_port_queue_capacity = 512;
+    static constexpr uint32_t shm_default_healthy_check_timeout_ms = 1000;
+
     //! Destructor
     virtual ~SharedMemTransportDescriptor() = default;
 
@@ -154,13 +159,13 @@ struct SharedMemTransportDescriptor : public PortBasedTransportDescriptor
 
 private:
 
-    uint32_t segment_size_;
-    uint32_t port_queue_capacity_;
-    uint32_t healthy_check_timeout_ms_;
-    std::string rtps_dump_file_;
+    uint32_t segment_size_ = shm_default_segment_size;
+    uint32_t port_queue_capacity_ = shm_default_port_queue_capacity;
+    uint32_t healthy_check_timeout_ms_ = shm_default_healthy_check_timeout_ms;
+    std::string rtps_dump_file_ {""};
 
     //! Thread settings for the transport dump thread
-    ThreadSettings dump_thread_;
+    ThreadSettings dump_thread_ {};
 
 };
 

src/cpp/rtps/transport/shared_mem/SharedMemTransport.cpp

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include <algorithm>
+#include <cstdint>
 #include <cstring>
 #include <thread>
 #include <utility>
@@ -26,6 +27,7 @@
 #include <fastdds/rtps/common/Locator.hpp>
 #include <fastdds/rtps/transport/SenderResource.hpp>
 #include <fastdds/rtps/transport/TransportInterface.hpp>
+#include <fastdds/rtps/transport/shared_mem/SharedMemTransportDescriptor.hpp>
 
 #include <rtps/messages/CDRMessage.hpp>
 #include <rtps/messages/MessageReceiver.h>
@@ -45,6 +47,9 @@ namespace eprosima {
 namespace fastdds {
 namespace rtps {
 
+// TODO(Adolfo): Calculate this value from UDP sockets buffers size.
+static constexpr uint32_t shm_default_segment_size = 512 * 1024;
+
 TransportInterface* SharedMemTransportDescriptor::create_transport() const
 {
     return new SharedMemTransport(*this);
@@ -271,8 +276,6 @@ bool SharedMemTransport::init(
         const uint32_t& max_msg_size_no_frag)
 {
     (void) max_msg_size_no_frag;
-    // TODO(Adolfo): Calculate this value from UDP sockets buffers size.
-    static constexpr uint32_t shm_default_segment_size = 512 * 1024;
 
     if (configuration_.segment_size() == 0)
     {
@@ -301,8 +304,14 @@ bool SharedMemTransport::init(
         {
             return false;
         }
-        shared_mem_segment_ = shared_mem_manager_->create_segment(configuration_.segment_size(),
-                        configuration_.port_queue_capacity());
+        constexpr uint32_t mean_message_size =
+                shm_default_segment_size / SharedMemTransportDescriptor::shm_default_port_queue_capacity;
+        uint32_t max_allocations = configuration_.segment_size() / mean_message_size;
+        if (configuration_.port_queue_capacity() > max_allocations)
+        {
+            max_allocations = configuration_.port_queue_capacity();
+        }
+        shared_mem_segment_ = shared_mem_manager_->create_segment(configuration_.segment_size(), max_allocations);
 
         // Memset the whole segment to zero in order to force physical map of the buffer
         auto buffer = shared_mem_segment_->alloc_buffer(configuration_.segment_size(),

src/cpp/rtps/transport/shared_mem/SharedMemTransportDescriptor.cpp

@@ -23,19 +23,11 @@ namespace eprosima {
 namespace fastdds {
 namespace rtps {
 
-static constexpr uint32_t shm_default_segment_size = 0;
-static constexpr uint32_t shm_default_port_queue_capacity = 512;
-static constexpr uint32_t shm_default_healthy_check_timeout_ms = 1000;
-
 //*********************************************************
 // SharedMemTransportDescriptor
 //*********************************************************
 SharedMemTransportDescriptor::SharedMemTransportDescriptor()
     : PortBasedTransportDescriptor(shm_default_segment_size, s_maximumInitialPeersRange)
-    , segment_size_(shm_default_segment_size)
-    , port_queue_capacity_(shm_default_port_queue_capacity)
-    , healthy_check_timeout_ms_(shm_default_healthy_check_timeout_ms)
-    , rtps_dump_file_("")
 {
     maxMessageSize = s_maximumMessageSize;
 }

test/mock/rtps/SharedMemTransportDescriptor/fastdds/rtps/transport/shared_mem/SharedMemTransportDescriptor.hpp

@@ -37,8 +37,12 @@ class TransportInterface;
  *
  * @ingroup TRANSPORT_MODULE
  */
-typedef struct SharedMemTransportDescriptor : public PortBasedTransportDescriptor
+struct SharedMemTransportDescriptor : public PortBasedTransportDescriptor
 {
+    static constexpr uint32_t shm_default_segment_size = 0;
+    static constexpr uint32_t shm_default_port_queue_capacity = 512;
+    static constexpr uint32_t shm_default_healthy_check_timeout_ms = 1000;
+
     virtual ~SharedMemTransportDescriptor()
     {
 
@@ -130,13 +134,13 @@ typedef struct SharedMemTransportDescriptor : public PortBasedTransportDescripto
 
 private:
 
-    uint32_t segment_size_;
-    uint32_t port_queue_capacity_;
-    uint32_t healthy_check_timeout_ms_;
+    uint32_t segment_size_ = shm_default_segment_size;
+    uint32_t port_queue_capacity_ = shm_default_port_queue_capacity;
+    uint32_t healthy_check_timeout_ms_ = shm_default_healthy_check_timeout_ms;
     std::string rtps_dump_file_;
     ThreadSettings dump_thread_;
 
-}SharedMemTransportDescriptor;
+};
 
 } // namespace rtps
 } // namespace fastdds