diff --git a/quarkchain/cluster/master.py b/quarkchain/cluster/master.py
index 53c64c50b..58d5eb2d8 100644
--- a/quarkchain/cluster/master.py
+++ b/quarkchain/cluster/master.py
@@ -1529,6 +1529,33 @@ def parse_args():
 
     return env
 
+async def tracemalloc_snapshot(env):
+    import tracemalloc
+    tracemalloc.start(25)
+    snapshot_old = None
+
+    # vmprof ***
+    import vmprof
+    import os
+    f=os.open("./vmprofout",  os.O_RDWR|os.O_CREAT)
+    vmprof.enable(f, period=0.5, memory=True) # 2 Hz, see https://github.com/blue-yonder/vmprof-viewer-client
+
+    while True:
+        # tracemalloc ***
+        ts = int(time.time())
+        snapshot_new = tracemalloc.take_snapshot()
+        fn = "./mem/{}".format(ts)
+        snapshot_new.dump(fn)
+        Logger.warning("dumped mem snapshot to {}".format(fn))
+
+        if snapshot_old:
+            diff = snapshot_new.compare_to(snapshot_old, 'lineno')
+            Logger.warning("[ Top 10 differences ]")
+            for stat in diff[:10]:
+                Logger.warning(stat)
+        snapshot_old = snapshot_new
+        await asyncio.sleep(60)
+
 
 def main():
     from quarkchain.cluster.jsonrpc import JSONRPCServer
@@ -1555,6 +1582,8 @@ def main():
     public_json_rpc_server = JSONRPCServer.start_public_server(env, master)
     private_json_rpc_server = JSONRPCServer.start_private_server(env, master)
 
+    asyncio.ensure_future(tracemalloc_snapshot(env))
+
     try:
         loop.run_until_complete(master.shutdown_future)
     except KeyboardInterrupt:
diff --git a/quarkchain/cluster/slave.py b/quarkchain/cluster/slave.py
index e6a6e3191..ca76be7d4 100644
--- a/quarkchain/cluster/slave.py
+++ b/quarkchain/cluster/slave.py
@@ -788,6 +788,56 @@ async def connect_to_slave(self, slave_info: SlaveInfo) -> str:
         return ""
 
 
+async def tracemalloc_snapshot(slave):
+    slave_id = slave.id.decode('ascii')
+    import tracemalloc
+    import time
+    tracemalloc.start(25)
+    snapshot_old = None
+
+    # vmprof ***
+    import vmprof
+    import os
+    f=os.open("./vmprofout{}".format(slave_id), os.O_RDWR|os.O_CREAT)
+    vmprof.enable(f, period=0.5, memory=True) # 2 Hz, see https://github.com/blue-yonder/vmprof-viewer-client
+
+    import pathlib
+    pathlib.Path("./mem{}".format(slave_id)).mkdir(parents=True, exist_ok=True)
+
+    import objgraph
+
+    while True:
+        # tracemalloc ***
+        ts = int(time.time())
+        snapshot_new = tracemalloc.take_snapshot()
+        fn = "./mem{}/{}".format(slave_id, ts)
+        snapshot_new.dump(fn)
+        Logger.warning("dumped mem snapshot to {}".format(fn))
+
+        if snapshot_old:
+            diff = snapshot_new.compare_to(snapshot_old, 'lineno')
+            Logger.warning("[ Top 10 differences ]")
+            for stat in diff[:10]:
+                Logger.warning(stat)
+        snapshot_old = snapshot_new
+        Logger.warning(objgraph.growth())
+        Logger.warning(objgraph.most_common_types(limit=20))
+        Logger.warning("slave.add_block_futures={}".format(len(slave.add_block_futures)))
+        for branch, shard in slave.shards.items():
+            Logger.warning("shard.state.new_block_pool={}".format(len(shard.state.new_block_pool)))
+
+            Logger.warning("shard.add_block_futures={}".format(len(shard.add_block_futures)))
+
+            Logger.warning("shard.state.db.m_header_pool={}".format(len(shard.state.db.m_header_pool)))
+            Logger.warning("shard.state.db.m_meta_pool={}".format(len(shard.state.db.m_meta_pool)))
+            Logger.warning("shard.state.db.x_shard_set={}".format(len(shard.state.db.x_shard_set)))
+            Logger.warning("shard.state.db.r_header_pool={}".format(len(shard.state.db.r_header_pool)))
+            Logger.warning("shard.state.db.r_minor_header_pool={}".format(len(shard.state.db.r_minor_header_pool)))
+            Logger.warning("shard.state.db.height_to_minor_block_hashes={}".format(len(shard.state.db.height_to_minor_block_hashes)))
+
+        await asyncio.sleep(60)
+
+
 class SlaveServer:
     """ Slave node in a cluster """
 
@@ -886,6 +936,7 @@ async def __start_server(self):
         )
 
     def start(self):
+        self.loop.create_task(tracemalloc_snapshot(self))
         self.loop.create_task(self.__start_server())
 
     def start_and_loop(self):
diff --git a/requirements.txt b/requirements.txt
index 01aaba5a5..f896c91e2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,6 +18,8 @@ eth-bloom==1.0.0
 pyethash>=0.1.27,<1.0.0
 py_ecc==1.4.3
 eth-hash[pycryptodome]==0.1.4
+vmprof==0.4.12
+objgraph==3.4.0
 
 # p2p
 pytest>=3.6,<3.7