Add 'adaptive_readahead' and 'async_io' options to db_stress (#9750)

Summary:
Same as title

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9750

Test Plan:
export CRASH_TEST_EXT_ARGS=" --async_io=1 --adaptive_readahead=1;
make -j crash_test

Reviewed By: jay-zhuang

Differential Revision: D35114326

Pulled By: akankshamahajan15

fbshipit-source-id: 8b05c95be09f7aff6cb9eb757aa20a6520349d45

db_stress_tool/db_stress_common.h

@@ -282,6 +282,9 @@ DECLARE_uint64(wp_snapshot_cache_bits);
 DECLARE_uint64(wp_commit_cache_bits);
 #endif  // !ROCKSDB_LITE
 
+DECLARE_bool(adaptive_readahead);
+DECLARE_bool(async_io);
+
 constexpr long KB = 1024;
 constexpr int kRandomValueMaxFactor = 3;
 constexpr int kValueMaxLen = 100;

db_stress_tool/db_stress_gflags.cc

@@ -912,4 +912,11 @@ DEFINE_uint64(wp_commit_cache_bits, 23ull,
               "commit cache. Default: 23 (8M entries)");
 #endif  // !ROCKSDB_LITE
 
+DEFINE_bool(adaptive_readahead, false,
+            "Carry forward internal auto readahead size from one file to next "
+            "file at each level during iteration");
+DEFINE_bool(
+    async_io, false,
+    "Does asynchronous prefetching when internal auto readahead is enabled");
+
 #endif  // GFLAGS

db_stress_tool/db_stress_test_base.cc

@@ -645,6 +645,8 @@ void StressTest::OperateDb(ThreadState* thread) {
   ReadOptions read_opts(FLAGS_verify_checksum, true);
   read_opts.rate_limiter_priority =
       FLAGS_rate_limit_user_ops ? Env::IO_USER : Env::IO_TOTAL;
+  read_opts.async_io = FLAGS_async_io;
+  read_opts.adaptive_readahead = FLAGS_adaptive_readahead;
   WriteOptions write_opts;
   if (FLAGS_rate_limit_auto_wal_flush) {
     write_opts.rate_limiter_priority = Env::IO_USER;

tools/db_crashtest.py

@@ -163,6 +163,8 @@ default_params = {
     "memtable_prefix_bloom_size_ratio": lambda: random.choice([0.001, 0.01, 0.1, 0.5]),
     "memtable_whole_key_filtering": lambda: random.randint(0, 1),
     "detect_filter_construct_corruption": lambda: random.choice([0, 1]),
+    "adaptive_readahead": lambda: random.choice([0, 1]),
+    "async_io": lambda: random.choice([0, 1]),
 }
 
 _TEST_DIR_ENV_VAR = 'TEST_TMPDIR'