Merge #2148: [Core] Prevector Optimizations 2

b886a4c Fix header guards using reserved identifiers (Dan Raviv)
b389b3f speed up Unserialize_impl for prevector (Akio Nakamura)
13d2102 Minimal fix to slow prevector tests as stopgap measure (Jeremy Rubin)

Pull request description:

  Backports bitcoin#12324.
  The `DeserializeAndCheckBlock` benchmark (introduced in #2146) shows a speedup of about 4% (not as much as the upstream PR, due to the optimizations already included in #2083).

  Cherry-picks also
  - bitcoin#8671 (with minimal changes to the random context, due to bitcoin#8914 and bitcoin#9792 being already ported out of order).
  - bitcoin#11151

ACKs for top commit:
  Fuzzbawls:
    utACK b886a4c
  furszy:
    utACK b886a4c and merging..

Tree-SHA512: f5de40e5acfb0b875d413d8995d71dd90489730fe4853f0be03d76a1c44ec95eaeb28c0c40d8e91906f23529ad26501bda4f9779ce466cd8603ed97f1662ca98

src/cuckoocache.h

@@ -2,8 +2,8 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#ifndef _BITCOIN_CUCKOOCACHE_H_
-#define _BITCOIN_CUCKOOCACHE_H_
+#ifndef BITCOIN_CUCKOOCACHE_H
+#define BITCOIN_CUCKOOCACHE_H
 
 #include <array>
 #include <algorithm>
@@ -454,4 +454,4 @@ class cache
 };
 } // namespace CuckooCache
 
-#endif
+#endif // BITCOIN_CUCKOOCACHE_H

src/prevector.h

@@ -2,8 +2,8 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#ifndef _BITCOIN_PREVECTOR_H_
-#define _BITCOIN_PREVECTOR_H_
+#ifndef BITCOIN_PREVECTOR_H
+#define BITCOIN_PREVECTOR_H
 
 #include <assert.h>
 #include <stdlib.h>
@@ -381,6 +381,21 @@ class prevector {
         }
     }
 
+    inline void resize_uninitialized(size_type new_size) {
+        // resize_uninitialized changes the size of the prevector but does not initialize it.
+        // If size < new_size, the added elements must be initialized explicitly.
+        if (capacity() < new_size) {
+            change_capacity(new_size);
+            _size += new_size - size();
+            return;
+        }
+        if (new_size < size()) {
+            erase(item_ptr(new_size), end());
+        } else {
+            _size += new_size - size();
+        }
+    }
+
     iterator erase(iterator pos) {
         return erase(pos, pos + 1);
     }
@@ -513,4 +528,4 @@ class prevector {
 };
 #pragma pack(pop)
 
-#endif
+#endif // BITCOIN_PREVECTOR_H

src/serialize.h

@@ -803,7 +803,7 @@ void Unserialize_impl(Stream& is, prevector<N, T>& v, const unsigned char&)
     while (i < nSize)
     {
         unsigned int blk = std::min(nSize - i, (unsigned int)(1 + 4999999 / sizeof(T)));
-        v.resize(i + blk);
+        v.resize_uninitialized(i + blk);
         is.read((char*)&v[i], blk * sizeof(T));
         i += blk;
     }
@@ -821,8 +821,8 @@ void Unserialize_impl(Stream& is, prevector<N, T>& v, const V&)
         nMid += 5000000 / sizeof(T);
         if (nMid > nSize)
             nMid = nSize;
-        v.resize(nMid);
-        for (; i < nMid; i++)
+        v.resize_uninitialized(nMid);
+        for (; i < nMid; ++i)
             Unserialize(is, v[i]);
     }
 }

src/test/prevector_tests.cpp

@@ -26,53 +26,66 @@ class prevector_tester {
     pretype pre_vector_alt;
 
     typedef typename pretype::size_type Size;
+    bool passed = true;
+    FastRandomContext rand_cache;
+    uint256 rand_seed;
 
+    template <typename A, typename B>
+        void local_check_equal(A a, B b)
+        {
+            local_check(a == b);
+        }
+    void local_check(bool b)
+    {
+        passed &= b;
+    }
     void test() {
         const pretype& const_pre_vector = pre_vector;
-        BOOST_CHECK_EQUAL(real_vector.size(), pre_vector.size());
-        BOOST_CHECK_EQUAL(real_vector.empty(), pre_vector.empty());
+        local_check_equal(real_vector.size(), pre_vector.size());
+        local_check_equal(real_vector.empty(), pre_vector.empty());
         for (Size s = 0; s < real_vector.size(); s++) {
-             BOOST_CHECK(real_vector[s] == pre_vector[s]);
-             BOOST_CHECK(&(pre_vector[s]) == &(pre_vector.begin()[s]));
-             BOOST_CHECK(&(pre_vector[s]) == &*(pre_vector.begin() + s));
-             BOOST_CHECK(&(pre_vector[s]) == &*((pre_vector.end() + s) - real_vector.size()));
+             local_check(real_vector[s] == pre_vector[s]);
+             local_check(&(pre_vector[s]) == &(pre_vector.begin()[s]));
+             local_check(&(pre_vector[s]) == &*(pre_vector.begin() + s));
+             local_check(&(pre_vector[s]) == &*((pre_vector.end() + s) - real_vector.size()));
         }
-        // BOOST_CHECK(realtype(pre_vector) == real_vector);
-        BOOST_CHECK(pretype(real_vector.begin(), real_vector.end()) == pre_vector);
-        BOOST_CHECK(pretype(pre_vector.begin(), pre_vector.end()) == pre_vector);
+        // local_check(realtype(pre_vector) == real_vector);
+        local_check(pretype(real_vector.begin(), real_vector.end()) == pre_vector);
+        local_check(pretype(pre_vector.begin(), pre_vector.end()) == pre_vector);
         size_t pos = 0;
+
         for (const T& v  : pre_vector) {
-             BOOST_CHECK(v == real_vector[pos++]);
+            local_check(v == real_vector[pos++]);
         }
         pos = 0;
         for (const T& v : const_pre_vector) {
-             BOOST_CHECK(v == real_vector[pos++]);
+            local_check(v == real_vector[pos++]);
         }
 
         CDataStream ss1(SER_DISK, 0);
         CDataStream ss2(SER_DISK, 0);
         ss1 << real_vector;
         ss2 << pre_vector;
-        BOOST_CHECK_EQUAL(ss1.size(), ss2.size());
+        local_check_equal(ss1.size(), ss2.size());
         for (Size s = 0; s < ss1.size(); s++) {
-            BOOST_CHECK_EQUAL(ss1[s], ss2[s]);
+            local_check_equal(ss1[s], ss2[s]);
         }
     }
 
 public:
     void resize(Size s) {
         real_vector.resize(s);
-        BOOST_CHECK_EQUAL(real_vector.size(), s);
+        local_check_equal(real_vector.size(), s);
         pre_vector.resize(s);
-        BOOST_CHECK_EQUAL(pre_vector.size(), s);
+        local_check_equal(pre_vector.size(), s);
         test();
     }
 
     void reserve(Size s) {
         real_vector.reserve(s);
-        BOOST_CHECK(real_vector.capacity() >= s);
+        local_check(real_vector.capacity() >= s);
         pre_vector.reserve(s);
-        BOOST_CHECK(pre_vector.capacity() >= s);
+        local_check(pre_vector.capacity() >= s);
         test();
     }
 
@@ -165,6 +178,35 @@ class prevector_tester {
         real_vector = real_vector_alt;
         pre_vector = pre_vector_alt;
     }
+
+    void resize_uninitialized(realtype values) {
+        size_t r = values.size();
+        size_t s = real_vector.size() / 2;
+        if (real_vector.capacity() < s + r) {
+            real_vector.reserve(s + r);
+        }
+        real_vector.resize(s);
+        pre_vector.resize_uninitialized(s);
+        for (auto v : values) {
+            real_vector.push_back(v);
+        }
+        auto p = pre_vector.size();
+        pre_vector.resize_uninitialized(p + r);
+        for (auto v : values) {
+            pre_vector[p] = v;
+            ++p;
+        }
+        test();
+    }
+
+    ~prevector_tester() {
+        BOOST_CHECK_MESSAGE(passed, "insecure_rand: " + rand_seed.ToString());
+    }
+    prevector_tester() {
+        SeedInsecureRand();
+        rand_seed = InsecureRand256();
+        rand_cache = FastRandomContext(rand_seed);
+    }
 };
 
 BOOST_AUTO_TEST_CASE(PrevectorTestInt)
@@ -235,6 +277,14 @@ BOOST_AUTO_TEST_CASE(PrevectorTestInt)
             if (((r >> 15) % 32) == 18) {
                 test.move();
             }
+            if (InsecureRandBits(5) == 19) {
+                unsigned int num = 1 + (InsecureRandBits(4));
+                std::vector<int> values(num);
+                for (auto &v : values) {
+                    v = InsecureRand32();
+                }
+                test.resize_uninitialized(values);
+            }
         }
     }
 }