From 7b192945eb8378d6e3e245f76a15dc21a123736a Mon Sep 17 00:00:00 2001
From: seelabs <scott.determan@yahoo.com>
Date: Wed, 16 Dec 2020 18:08:04 -0500
Subject: [PATCH] Replace std::pmr with boost::pmr:

gcc's implementation of `prm::synchronized_pool_resource` showed
extremely poor performance compared with
`boost::synchronized_pool_resouece`. Boost's implementation of pmr is
now used in all cases (previously it was only used when a standard
lib, like clang's, lacked an implementation of pmr).

This patch also makes a minor change where inner nodes are constructed
with sparse arrays, unless "dense" is explicitly requested.
---
 src/ripple/shamap/SHAMapInnerNode.h      |  2 +-
 src/ripple/shamap/impl/TaggedPointer.ipp | 45 ------------------------
 2 files changed, 1 insertion(+), 46 deletions(-)

diff --git a/src/ripple/shamap/SHAMapInnerNode.h b/src/ripple/shamap/SHAMapInnerNode.h
index 43328eb6b..db7244e70 100644
--- a/src/ripple/shamap/SHAMapInnerNode.h
+++ b/src/ripple/shamap/SHAMapInnerNode.h
@@ -103,7 +103,7 @@ private:
 public:
     explicit SHAMapInnerNode(
         std::uint32_t cowid,
-        std::uint8_t numAllocatedChildren = branchFactor);
+        std::uint8_t numAllocatedChildren = 2);
 
     SHAMapInnerNode(SHAMapInnerNode const&) = delete;
     SHAMapInnerNode&
diff --git a/src/ripple/shamap/impl/TaggedPointer.ipp b/src/ripple/shamap/impl/TaggedPointer.ipp
index c97b7433e..62e43cfe0 100644
--- a/src/ripple/shamap/impl/TaggedPointer.ipp
+++ b/src/ripple/shamap/impl/TaggedPointer.ipp
@@ -23,18 +23,7 @@
 
 #include <array>
 
-// #define FORCE_BOOST_POOL 1
-#if FORCE_BOOST_POOL || !__has_include(<memory_resource>)
-#define USE_BOOST_POOL 1
-#else
-#define USE_BOOST_POOL 0
-#endif
-
-#if USE_BOOST_POOL
 #include <boost/pool/pool_alloc.hpp>
-#else
-#include <memory_resource>
-#endif
 
 namespace ripple {
 
@@ -102,8 +91,6 @@ boundariesIndex(std::uint8_t numChildren)
         std::lower_bound(boundaries.begin(), boundaries.end(), numChildren));
 }
 
-#if USE_BOOST_POOL
-
 template <std::size_t... I>
 std::array<std::function<void*()>, boundaries.size()> initAllocateArrayFuns(
     std::index_sequence<I...>)
@@ -171,38 +158,6 @@ deallocateArrays(std::uint8_t boundaryIndex, void* p)
     assert(isFromArrayFuns[boundaryIndex](p));
     freeArrayFuns[boundaryIndex](p);
 }
-#else
-
-template <std::size_t... I>
-std::array<std::pmr::synchronized_pool_resource, boundaries.size()>
-    initPmrArrayFuns(std::index_sequence<I...>)
-{
-    return std::array<std::pmr::synchronized_pool_resource, boundaries.size()>{
-        std::pmr::synchronized_pool_resource{std::pmr::pool_options{
-            /* max_blocks_per_chunk */ chunksPerBlock[I],
-            /* largest_required_pool_block */ chunksPerBlock[I]}}...,
-    };
-}
-std::array<std::pmr::synchronized_pool_resource, boundaries.size()>
-    pmrArrayFuns =
-        initPmrArrayFuns(std::make_index_sequence<boundaries.size()>{});
-
-// This function returns an untagged pointer
-[[nodiscard]] inline std::pair<std::uint8_t, void*>
-allocateArrays(std::uint8_t numChildren)
-{
-    auto const i = boundariesIndex(numChildren);
-    return {i, pmrArrayFuns[i].allocate(arrayChunkSizeBytes[i])};
-}
-
-// This function takes an untagged pointer
-inline void
-deallocateArrays(std::uint8_t boundaryIndex, void* p)
-{
-    return pmrArrayFuns[boundaryIndex].deallocate(
-        p, arrayChunkSizeBytes[boundaryIndex]);
-}
-#endif
 
 [[nodiscard]] inline int
 popcnt16(std::uint16_t a)