From 5495fa585007b40b2e9285c23be275de71708af8 Mon Sep 17 00:00:00 2001
From: Jeremy Rubin <j@rubin.io>
Date: Wed, 24 Jul 2019 13:36:47 -0700
Subject: [PATCH] Add Hash Padding Microbenchmarks

---
 src/Makefile.bench.include |  1 +
 src/bench/hashpadding.cpp  | 47 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 src/bench/hashpadding.cpp

diff --git a/src/Makefile.bench.include b/src/Makefile.bench.include
index 766c0fca5..93b5156af 100644
--- a/src/Makefile.bench.include
+++ b/src/Makefile.bench.include
@@ -29,6 +29,7 @@ bench_bench_bitcoin_SOURCES = \
   bench/crypto_hash.cpp \
   bench/ccoins_caching.cpp \
   bench/gcs_filter.cpp \
+  bench/hashpadding.cpp \
   bench/merkle_root.cpp \
   bench/mempool_eviction.cpp \
   bench/mempool_stress.cpp \
diff --git a/src/bench/hashpadding.cpp b/src/bench/hashpadding.cpp
new file mode 100644
index 000000000..985be8bdb
--- /dev/null
+++ b/src/bench/hashpadding.cpp
@@ -0,0 +1,47 @@
+// Copyright (c) 2015-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <bench/bench.h>
+#include <hash.h>
+#include <random.h>
+#include <uint256.h>
+
+
+static void PrePadded(benchmark::State& state)
+{
+
+    CSHA256 hasher;
+
+    // Setup the salted hasher
+    uint256 nonce = GetRandHash();
+    hasher.Write(nonce.begin(), 32);
+    hasher.Write(nonce.begin(), 32);
+    uint256 data = GetRandHash();
+    while (state.KeepRunning()) {
+        unsigned char out[32];
+        CSHA256 h = hasher;
+        h.Write(data.begin(), 32);
+        h.Finalize(out);
+    }
+}
+
+BENCHMARK(PrePadded, 10000);
+
+static void RegularPadded(benchmark::State& state)
+{
+    CSHA256 hasher;
+
+    // Setup the salted hasher
+    uint256 nonce = GetRandHash();
+    uint256 data = GetRandHash();
+    while (state.KeepRunning()) {
+        unsigned char out[32];
+        CSHA256 h = hasher;
+        h.Write(nonce.begin(), 32);
+        h.Write(data.begin(), 32);
+        h.Finalize(out);
+    }
+}
+
+BENCHMARK(RegularPadded, 10000);