API change: cbits now uses container pointers args in all member functions, except clone() ... for now. All containers may get same treatment! which will be a rather big API change. This was needed after testing fixed size cbits performance with pass-by-value: was very slow for large bitsets: now faster than std::bitset<>. Also reverted previous cbits_set_value(): much faster because it is branchless.

1 files changed, 123 insertions, 0 deletions

diff --git a/benchmarks/misc/cbits_benchmark.cpp b/benchmarks/misc/cbits_benchmark.cpp
new file mode 100644
index 00000000..50e19a7c
--- /dev/null
+++ b/benchmarks/misc/cbits_benchmark.cpp
@@ -0,0 +1,123 @@
+#include <iostream>
+#include <bitset>
+#include <cstdlib> // rand
+#include <ctime> // timer
+
+enum{ N=1<<22 }; // 4.2 mill.
+
+#include <stc/crandom.h>
+#define i_type cbits
+#define i_len N
+#include <stc/cbits.h>
+
+inline unsigned long get_time_in_ms()
+{
+    return (unsigned long)(1000 * clock() / CLOCKS_PER_SEC);
+}
+
+
+void one_sec_delay()
+{
+    unsigned long end_time = get_time_in_ms() + 1000;
+
+    while(get_time_in_ms() < end_time)
+    {
+    }
+}
+
+
+int main(int argc, char **argv)
+{
+    size_t seed = time(NULL);
+
+    using namespace std;
+    bool *bools = new bool[N];
+
+    unsigned long current_time, difference1, difference2;
+    uint64_t total;
+
+    one_sec_delay();
+
+    total = 0;
+    csrandom(seed);
+    current_time = get_time_in_ms();
+
+    c_forrange (40 * N)
+    {
+        uint64_t r = crandom();
+        bools[r & (N-1)] = r & 1<<29;
+    }
+
+    difference1 = get_time_in_ms() - current_time;
+    current_time = get_time_in_ms();
+
+    c_forrange (100) c_forrange (num, N) 
+    {
+        total += bools[num];
+    }
+
+    delete [] bools;
+
+    difference2 = get_time_in_ms() - current_time;
+
+    cout << "Bool:" << endl << "sum total = " << total << ", random access time = " << difference1 
+                            << ", sequential access time = " << difference2 << endl << endl;
+
+    one_sec_delay();
+
+    total = 0;
+    csrandom(seed);
+    current_time = get_time_in_ms();
+    bitset<N> bits;
+
+    c_forrange (40 * N)
+    {
+        uint64_t r = crandom();
+        bits[r & (N-1)] = r & 1<<29;
+    }
+
+    difference1 = get_time_in_ms() - current_time;
+    current_time = get_time_in_ms();
+
+    c_forrange (100) c_forrange (num, N)
+    {
+        total += bits[num];
+    }   
+
+    difference2 = get_time_in_ms() - current_time;
+
+    cout << "Bitset:" << endl << "sum total = " << total << ", random access time = " << difference1
+                              << ", sequential access time = " << difference2 << endl << endl;
+
+    one_sec_delay();
+
+    total = 0;
+    csrandom(seed);
+    current_time = get_time_in_ms();
+    cbits bits2 = cbits_with_size(N, false);
+
+    c_forrange (40 * N)
+    {
+        uint64_t r = crandom();
+        cbits_set_value(&bits2, r & (N-1), r & 1<<29);
+    }
+
+    difference1 = get_time_in_ms() - current_time;
+    current_time = get_time_in_ms();
+
+    c_forrange (100) c_forrange (num, N)
+    {
+        total += cbits_at(&bits2, num);
+    }
+
+    cbits_drop(&bits2);
+
+    difference2 = get_time_in_ms() - current_time;
+
+    cout << "cbits:" << endl << "sum total = " << total << ", random access time = " << difference1
+                              << ", sequential access time = " << difference2 << endl << endl;
+
+    //cin.get();
+
+    return 0;
+}