6 files changed, 163 insertions, 1 deletions

diff --git a/src/backends/cl/CMakeLists.txt b/src/backends/cl/CMakeLists.txt
index d751854c92..dd2a4a12b1 100644
--- a/src/backends/cl/CMakeLists.txt
+++ b/src/backends/cl/CMakeLists.txt
@@ -7,6 +7,8 @@ if(ARMCOMPUTECL)
     list(APPEND armnnClBackend_sources
         ClBackend.cpp
         ClBackend.hpp
+        ClBackendContext.cpp
+        ClBackendContext.hpp
         ClBackendId.hpp
         ClContextControl.cpp
         ClContextControl.hpp
diff --git a/src/backends/cl/ClBackend.cpp b/src/backends/cl/ClBackend.cpp
index b1857a3678..c07fa66457 100644
--- a/src/backends/cl/ClBackend.cpp
+++ b/src/backends/cl/ClBackend.cpp
@@ -6,6 +6,7 @@
 #include "ClBackend.hpp"
 #include "ClBackendId.hpp"
 #include "ClWorkloadFactory.hpp"
+#include "ClBackendContext.hpp"
 
 #include <backendsCommon/BackendRegistry.hpp>
 
@@ -38,4 +39,11 @@ IBackendInternal::IWorkloadFactoryPtr ClBackend::CreateWorkloadFactory() const
     return std::make_unique<ClWorkloadFactory>();
 }
 
+IBackendInternal::IBackendContextPtr
+ClBackend::CreateBackendContext(const IRuntime::CreationOptions& options) const
+{
+    return IBackendContextPtr{new ClBackendContext{options}};
+}
+
+
 } // namespace armnn
diff --git a/src/backends/cl/ClBackend.hpp b/src/backends/cl/ClBackend.hpp
index 223aeb3095..f8a6253c22 100644
--- a/src/backends/cl/ClBackend.hpp
+++ b/src/backends/cl/ClBackend.hpp
@@ -4,6 +4,7 @@
 //
 #pragma once
 
+#include <backendsCommon/IBackendContext.hpp>
 #include <backendsCommon/IBackendInternal.hpp>
 
 namespace armnn
@@ -18,7 +19,8 @@ public:
     static const BackendId& GetIdStatic();
     const BackendId& GetId() const override { return GetIdStatic(); }
 
-    IWorkloadFactoryPtr CreateWorkloadFactory() const override;
+    IBackendInternal::IWorkloadFactoryPtr CreateWorkloadFactory() const override;
+    IBackendInternal::IBackendContextPtr CreateBackendContext(const IRuntime::CreationOptions&) const override;
 };
 
 } // namespace armnn
\ No newline at end of file
diff --git a/src/backends/cl/ClBackendContext.cpp b/src/backends/cl/ClBackendContext.cpp
new file mode 100644
index 0000000000..a2c1b87359
--- /dev/null
+++ b/src/backends/cl/ClBackendContext.cpp
@@ -0,0 +1,113 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "ClBackendContext.hpp"
+#include "ClContextControl.hpp"
+
+#include <boost/log/trivial.hpp>
+
+#ifdef ARMCOMPUTECL_ENABLED
+#include <arm_compute/core/CL/OpenCL.h>
+#include <arm_compute/core/CL/CLKernelLibrary.h>
+#include <arm_compute/runtime/CL/CLScheduler.h>
+#endif
+
+namespace armnn
+{
+
+struct ClBackendContext::ClContextControlWrapper
+{
+    ClContextControlWrapper(IGpuAccTunedParameters* clTunedParameters,
+                            bool profilingEnabled)
+        : m_ClContextControl(clTunedParameters, profilingEnabled)
+    {}
+
+    bool Sync()
+    {
+#ifdef ARMCOMPUTECL_ENABLED
+        if (arm_compute::CLScheduler::get().context()() != NULL)
+        {
+            // Waits for all queued CL requests to finish before unloading the network they may be using.
+            try
+            {
+                // Coverity fix: arm_compute::CLScheduler::sync() may throw an exception of type cl::Error.
+                arm_compute::CLScheduler::get().sync();
+            }
+            catch (const cl::Error&)
+            {
+                BOOST_LOG_TRIVIAL(warning) << "WARNING: Runtime::UnloadNetwork(): an error occurred while waiting for "
+                                            "the queued CL requests to finish";
+                return false;
+            }
+        }
+#endif
+        return true;
+    }
+
+    void ClearClCache()
+    {
+#ifdef ARMCOMPUTECL_ENABLED
+        if (arm_compute::CLScheduler::get().context()() != NULL)
+        {
+            // There are no loaded networks left, so clear the CL cache to free up memory
+            m_ClContextControl.ClearClCache();
+        }
+#endif
+    }
+
+
+    ClContextControl m_ClContextControl;
+};
+
+
+ClBackendContext::ClBackendContext(const IRuntime::CreationOptions& options)
+    : IBackendContext(options)
+    , m_ClContextControlWrapper(
+        std::make_unique<ClContextControlWrapper>(options.m_GpuAccTunedParameters.get(),
+                                                  options.m_EnableGpuProfiling))
+{
+}
+
+bool ClBackendContext::BeforeLoadNetwork(NetworkId)
+{
+    return true;
+}
+
+bool ClBackendContext::AfterLoadNetwork(NetworkId networkId)
+{
+    {
+        std::lock_guard<std::mutex> lockGuard(m_Mutex);
+        m_NetworkIds.insert(networkId);
+    }
+    return true;
+}
+
+bool ClBackendContext::BeforeUnloadNetwork(NetworkId)
+{
+    return m_ClContextControlWrapper->Sync();
+}
+
+bool ClBackendContext::AfterUnloadNetwork(NetworkId networkId)
+{
+    bool clearCache = false;
+    {
+        std::lock_guard<std::mutex> lockGuard(m_Mutex);
+        m_NetworkIds.erase(networkId);
+        clearCache = m_NetworkIds.empty();
+    }
+
+    if (clearCache)
+    {
+        m_ClContextControlWrapper->ClearClCache();
+    }
+
+    return true;
+}
+
+ClBackendContext::~ClBackendContext()
+{
+}
+
+} // namespace armnn
\ No newline at end of file
diff --git a/src/backends/cl/ClBackendContext.hpp b/src/backends/cl/ClBackendContext.hpp
new file mode 100644
index 0000000000..24497c2249
--- /dev/null
+++ b/src/backends/cl/ClBackendContext.hpp
@@ -0,0 +1,36 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+#pragma once
+
+#include <backendsCommon/IBackendContext.hpp>
+#include <unordered_set>
+#include <mutex>
+
+namespace armnn
+{
+
+class ClBackendContext : public IBackendContext
+{
+public:
+    ClBackendContext(const IRuntime::CreationOptions& options);
+
+    bool BeforeLoadNetwork(NetworkId networkId) override;
+    bool AfterLoadNetwork(NetworkId networkId) override;
+
+    bool BeforeUnloadNetwork(NetworkId networkId) override;
+    bool AfterUnloadNetwork(NetworkId networkId) override;
+
+    ~ClBackendContext() override;
+
+private:
+    std::mutex m_Mutex;
+    struct ClContextControlWrapper;
+    std::unique_ptr<ClContextControlWrapper> m_ClContextControlWrapper;
+
+    std::unordered_set<NetworkId> m_NetworkIds;
+
+};
+
+} // namespace armnn
\ No newline at end of file
diff --git a/src/backends/cl/backend.mk b/src/backends/cl/backend.mk
index 97df8e4903..fd7ea80f33 100644
--- a/src/backends/cl/backend.mk
+++ b/src/backends/cl/backend.mk
@@ -9,6 +9,7 @@
 
 BACKEND_SOURCES := \
         ClBackend.cpp \
+        ClBackendContext.cpp \
         ClContextControl.cpp \
         ClLayerSupport.cpp \
         ClWorkloadFactory.cpp \