reduced memory churn using fixed_xxx containers (#236)

* Added EASTL to help with eliminating memory allocations
* Applied EASTL to eliminate memory allocations, primarily by using `fixed_vector` et al to use stack allocations / inline struct allocations

Reduces memory events in traces by close to a factor of 10 in test scenario (starting editor for project F)

1 files changed, 40 insertions, 33 deletions

diff --git a/src/zenstore/cache/cacherpc.cpp b/src/zenstore/cache/cacherpc.cpp
index cca51e63e..97e26a38d 100644
--- a/src/zenstore/cache/cacherpc.cpp
+++ b/src/zenstore/cache/cacherpc.cpp
@@ -20,6 +20,8 @@
 
 #include <zencore/memory/llm.h>
 
+#include <EASTL/fixed_vector.h>
+
 //////////////////////////////////////////////////////////////////////////
 
 namespace zen {
@@ -89,7 +91,7 @@ GetRpcRequestCacheKey(const CbObjectView& KeyView, CacheKey& Key)
 		return false;
 	}
 	IoHash Hash = HashField.AsHash();
-	Key			= CacheKey::Create(*Bucket, Hash);
+	Key			= CacheKey::CreateValidated(std::move(*Bucket), Hash);
 	return true;
 }
 
@@ -305,7 +307,7 @@ CacheRpcHandler::HandleRpcPutCacheRecords(const CacheRequestContext& Context, co
 	}
 	DefaultPolicy = !PolicyText.empty() ? ParseCachePolicy(PolicyText) : CachePolicy::Default;
 
-	std::vector<bool> Results;
+	eastl::fixed_vector<bool, 32> Results;
 
 	CbArrayView RequestsArray = Params["Requests"sv].AsArrayView();
 	for (CbFieldView RequestField : RequestsArray)
@@ -481,16 +483,15 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 		bool			 Exists			  = false;
 		bool			 ReadFromUpstream = false;
 	};
-	struct RecordRequestData
+	struct RecordRequestData : public CacheKeyRequest
 	{
-		CacheKeyRequest				  Upstream;
-		CbObjectView				  RecordObject;
-		IoBuffer					  RecordCacheValue;
-		CacheRecordPolicy			  DownstreamPolicy;
-		std::vector<ValueRequestData> Values;
-		bool						  Complete = false;
-		const UpstreamEndpointInfo*	  Source   = nullptr;
-		uint64_t					  ElapsedTimeUs;
+		CbObjectView							 RecordObject;
+		IoBuffer								 RecordCacheValue;
+		CacheRecordPolicy						 DownstreamPolicy;
+		eastl::fixed_vector<ValueRequestData, 4> Values;
+		bool									 Complete = false;
+		const UpstreamEndpointInfo*				 Source	  = nullptr;
+		uint64_t								 ElapsedTimeUs;
 	};
 
 	std::string_view		   PolicyText	 = Params["DefaultPolicy"sv].AsString();
@@ -503,8 +504,8 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 
 	const bool HasUpstream = m_UpstreamCache.IsActive();
 
-	std::vector<RecordRequestData> Requests;
-	std::vector<size_t>			   UpstreamIndexes;
+	eastl::fixed_vector<RecordRequestData, 16> Requests;
+	eastl::fixed_vector<size_t, 16>			   UpstreamIndexes;
 
 	auto ParseValues = [](RecordRequestData& Request) {
 		CbArrayView ValuesArray = Request.RecordObject["Values"sv].AsArrayView();
@@ -535,7 +536,7 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 		CbObjectView	   RequestObject = RequestField.AsObjectView();
 		CbObjectView	   KeyObject	 = RequestObject["Key"sv].AsObjectView();
 
-		CacheKey& Key = Request.Upstream.Key;
+		CacheKey& Key = Request.Key;
 		if (!GetRpcRequestCacheKey(KeyObject, Key))
 		{
 			return CbPackage{};
@@ -707,7 +708,7 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 		for (size_t Index : UpstreamIndexes)
 		{
 			RecordRequestData& Request = Requests[Index];
-			UpstreamRequests.push_back(&Request.Upstream);
+			UpstreamRequests.push_back(&Request);
 
 			if (Request.Values.size())
 			{
@@ -721,13 +722,13 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 					UpstreamPolicy |= !Value.ReadFromUpstream ? CachePolicy::SkipData : CachePolicy::None;
 					Builder.AddValuePolicy(Value.ValueId, UpstreamPolicy);
 				}
-				Request.Upstream.Policy = Builder.Build();
+				Request.Policy = Builder.Build();
 			}
 			else
 			{
 				// We don't know which Values exist in the Record; ask the upstrem for all values that the client wants,
 				// and convert the CacheRecordPolicy to an upstream policy
-				Request.Upstream.Policy = Request.DownstreamPolicy.ConvertToUpstream();
+				Request.Policy = Request.DownstreamPolicy.ConvertToUpstream();
 			}
 		}
 
@@ -737,10 +738,9 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 				return;
 			}
 
-			RecordRequestData& Request =
-				*reinterpret_cast<RecordRequestData*>(reinterpret_cast<char*>(&Params.Request) - offsetof(RecordRequestData, Upstream));
+			RecordRequestData& Request = *static_cast<RecordRequestData*>(&Params.Request);
 			Request.ElapsedTimeUs += static_cast<uint64_t>(Params.ElapsedSeconds * 1000000.0);
-			const CacheKey& Key = Request.Upstream.Key;
+			const CacheKey& Key = Request.Key;
 			Stopwatch		Timer;
 			auto			TimeGuard = MakeGuard([&Timer, &Request]() { Request.ElapsedTimeUs += Timer.GetElapsedTimeUs(); });
 			if (!Request.RecordObject)
@@ -832,10 +832,12 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 		CbPackage	   ResponsePackage;
 		CbObjectWriter ResponseObject{2048};
 
+		ResponsePackage.ReserveAttachments(Requests.size());
+
 		ResponseObject.BeginArray("Result"sv);
 		for (RecordRequestData& Request : Requests)
 		{
-			const CacheKey& Key = Request.Upstream.Key;
+			const CacheKey& Key = Request.Key;
 			if (Request.Complete ||
 				(Request.RecordObject && EnumHasAllFlags(Request.DownstreamPolicy.GetRecordPolicy(), CachePolicy::PartialRecord)))
 			{
@@ -910,11 +912,12 @@ CacheRpcHandler::HandleRpcPutCacheValues(const CacheRequestContext& Context, con
 	const bool	HasUpstream	  = m_UpstreamCache.IsActive();
 	CbArrayView RequestsArray = Params["Requests"sv].AsArrayView();
 
-	std::vector<bool>	  BatchResults;
-	std::vector<size_t>	  BatchResultIndexes;
-	std::vector<bool>	  Results;
-	std::vector<CacheKey> UpstreamCacheKeys;
-	uint64_t			  RequestCount = RequestsArray.Num();
+	std::vector<bool>				  BatchResults;
+	eastl::fixed_vector<size_t, 32>	  BatchResultIndexes;
+	eastl::fixed_vector<bool, 32>	  Results;
+	eastl::fixed_vector<CacheKey, 32> UpstreamCacheKeys;
+
+	uint64_t RequestCount = RequestsArray.Num();
 	{
 		Results.reserve(RequestCount);
 		std::unique_ptr<ZenCacheStore::PutBatch> Batch;
@@ -1099,15 +1102,15 @@ CacheRpcHandler::HandleRpcGetCacheValues(const CacheRequestContext& Context, CbO
 		uint64_t		 RawSize = 0;
 		CompressedBuffer Result;
 	};
-	std::vector<RequestData> Requests;
+	eastl::fixed_vector<RequestData, 16> Requests;
 
-	std::vector<size_t> RemoteRequestIndexes;
+	eastl::fixed_vector<size_t, 16> RemoteRequestIndexes;
 
 	const bool HasUpstream = m_UpstreamCache.IsActive();
 
-	CbArrayView				   RequestsArray = Params["Requests"sv].AsArrayView();
-	std::vector<ZenCacheValue> CacheValues;
-	const uint64_t			   RequestCount = RequestsArray.Num();
+	CbArrayView		   RequestsArray = Params["Requests"sv].AsArrayView();
+	ZenCacheValueVec_t CacheValues;
+	const uint64_t	   RequestCount = RequestsArray.Num();
 	CacheValues.reserve(RequestCount);
 	{
 		std::unique_ptr<ZenCacheStore::GetBatch> Batch;
@@ -1136,7 +1139,6 @@ CacheRpcHandler::HandleRpcGetCacheValues(const CacheRequestContext& Context, CbO
 			CacheKey&	Key	   = Request.Key;
 			CachePolicy Policy = Request.Policy;
 
-			ZenCacheValue CacheValue;
 			if (EnumHasAllFlags(Policy, CachePolicy::QueryLocal))
 			{
 				if (Batch)
@@ -1276,6 +1278,9 @@ CacheRpcHandler::HandleRpcGetCacheValues(const CacheRequestContext& Context, CbO
 		ZEN_TRACE_CPU("Z$::RpcGetCacheValues::Response");
 		CbPackage	   RpcResponse;
 		CbObjectWriter ResponseObject{1024};
+
+		RpcResponse.ReserveAttachments(Requests.size());
+
 		ResponseObject.BeginArray("Result"sv);
 		for (const RequestData& Request : Requests)
 		{
@@ -1642,7 +1647,7 @@ CacheRpcHandler::GetLocalCacheValues(const CacheRequestContext&					Context,
 	using namespace cache::detail;
 	const bool HasUpstream = m_UpstreamCache.IsActive();
 
-	std::vector<ZenCacheValue> Chunks;
+	ZenCacheValueVec_t Chunks;
 	Chunks.reserve(ValueRequests.size());
 	{
 		std::unique_ptr<ZenCacheStore::GetBatch> Batch;
@@ -1796,6 +1801,8 @@ CacheRpcHandler::WriteGetCacheChunksResponse([[maybe_unused]] const CacheRequest
 	CbPackage	   RpcResponse;
 	CbObjectWriter Writer{1024};
 
+	RpcResponse.ReserveAttachments(Requests.size());
+
 	Writer.BeginArray("Result"sv);
 	for (ChunkRequest& Request : Requests)
 	{