Added db benchmarking tool

Author: vbuterin

ethereum/tests/benchmark_db.py

@@ -0,0 +1,20 @@
+from ethereum import trie, db, utils
+import sys
+
+
+def benchmark(size):
+    t = trie.Trie(db.EphemDB())
+    for i in range(size):
+        t.update(utils.sha3('k'+str(i)), utils.sha3('v'+str(i)))
+    sz = sum([len(v) for k, v in t.db.db.items()])
+    nsz = []
+    for i in range(min(size, 100)):
+        ldb = db.ListeningDB(t.db.db)
+        odb = t.db
+        t.db = ldb
+        t.get(utils.sha3('k'+str(i)))
+        nsz.append(sum([len(v) for k, v in ldb.kv.items()]))
+        t.db = odb
+    print sz, sum(nsz) // len(nsz)
+
+benchmark(int(sys.argv[1]) if len(sys.argv) > 1 else 1000)