From ae1c00e3391cce78055f0df952b2d239afc796de Mon Sep 17 00:00:00 2001
From: Denis Angell <dangell@transia.co>
Date: Fri, 9 Jun 2023 16:37:18 +0000
Subject: [PATCH] fix node size estimation (#4536)

Fix a bug in the `NODE_SIZE` auto-detection feature in `Config.cpp`.
Specifically, this patch corrects the calculation for the total amount
of RAM available, which was previously returned in bytes, but is now
being returned in units of the system's memory unit. Additionally, the
patch adjusts the node size based on the number of available hardware
threads of execution.
---
 src/ripple/core/impl/Config.cpp | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/src/ripple/core/impl/Config.cpp b/src/ripple/core/impl/Config.cpp
index 9aa250508..9a5e4d8e7 100644
--- a/src/ripple/core/impl/Config.cpp
+++ b/src/ripple/core/impl/Config.cpp
@@ -68,10 +68,8 @@ namespace detail {
 [[nodiscard]] std::uint64_t
 getMemorySize()
 {
-    struct sysinfo si;
-
-    if (sysinfo(&si) == 0)
-        return static_cast<std::uint64_t>(si.totalram);
+    if (struct sysinfo si; sysinfo(&si) == 0)
+        return static_cast<std::uint64_t>(si.totalram) * si.mem_unit;
 
     return 0;
 }
@@ -128,7 +126,7 @@ sizedItems
     {SizedItem::lgrDBCache,         {{      4,       8,      16,      32,     128 }}},
     {SizedItem::openFinalLimit,     {{      8,      16,      32,      64,     128 }}},
     {SizedItem::burstSize,          {{      4,       8,      16,      32,      48 }}},
-    {SizedItem::ramSizeGB,          {{      8,      12,      16,      24,      32 }}},
+    {SizedItem::ramSizeGB,          {{      6,       8,      12,      24,       0 }}},
     {SizedItem::accountIdCacheSize, {{  20047,   50053,   77081,  150061,  300007 }}}
 }};
 
@@ -265,7 +263,8 @@ getEnvVar(char const* name)
 }
 
 Config::Config()
-    : j_(beast::Journal::getNullSink()), ramSize_(detail::getMemorySize())
+    : j_(beast::Journal::getNullSink())
+    , ramSize_(detail::getMemorySize() / (1024 * 1024 * 1024))
 {
 }
 
@@ -290,22 +289,18 @@ Config::setupControl(bool bQuiet, bool bSilent, bool bStandalone)
             threshold.second.begin(),
             threshold.second.end(),
             [this](std::size_t limit) {
-                return (ramSize_ / (1024 * 1024 * 1024)) < limit;
+                return (limit == 0) || (ramSize_ < limit);
             });
 
+        assert(ns != threshold.second.end());
+
         if (ns != threshold.second.end())
             NODE_SIZE = std::distance(threshold.second.begin(), ns);
 
         // Adjust the size based on the number of hardware threads of
         // execution available to us:
-        if (auto const hc = std::thread::hardware_concurrency())
-        {
-            if (hc == 1)
-                NODE_SIZE = 0;
-
-            if (hc < 4)
-                NODE_SIZE = std::min<std::size_t>(NODE_SIZE, 1);
-        }
+        if (auto const hc = std::thread::hardware_concurrency(); hc != 0)
+            NODE_SIZE = std::min<std::size_t>(hc / 2, NODE_SIZE);
     }
 
     assert(NODE_SIZE <= 4);