core: tune performance (#73)

- Avoid using recursive function in critical path.
- Do not write through when using levelDB. Things put to
   levelDB would be safe from panic even we didn't force
   to write through every time.
- Dump count of confirmed blocks proposed by self.
- Avoid allocating variables in loop.
- Return length of acking node set, we only need that
   when total ordering.
- Fix potential bug: make sure win records updated when
   acking height vectors of candidates are changed.
- Keep dirty validators in slice.
- Add cache for objects to ease the pressure to garbage
   collector.
- Cache global acking status when total ordering.
- Add method to recycle blocks.
- Marshal JSON should be called once for each broadcast.
- Make updateWinRecord called in parallel.
- Log average / deviation of latencies when simulation
   finished.

1 files changed, 2 insertions, 10 deletions

diff --git a/blockdb/level-db.go b/blockdb/level-db.go
index dcceb2e..79099c0 100644
--- a/blockdb/level-db.go
+++ b/blockdb/level-db.go
@@ -21,7 +21,6 @@ import (
 	"encoding/json"
 
 	"github.com/syndtr/goleveldb/leveldb"
-	"github.com/syndtr/goleveldb/leveldb/opt"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
@@ -93,9 +92,7 @@ func (lvl *LevelDBBackedBlockDB) Update(block types.Block) (err error) {
 	err = lvl.db.Put(
 		[]byte(block.Hash[:]),
 		marshaled,
-		&opt.WriteOptions{
-			Sync: true,
-		})
+		nil)
 	if err != nil {
 		return
 	}
@@ -112,15 +109,10 @@ func (lvl *LevelDBBackedBlockDB) Put(block types.Block) (err error) {
 		err = ErrBlockExists
 		return
 	}
-	syncedOpt := &opt.WriteOptions{
-		// We should force to sync for each write, it's safer
-		// from crash.
-		Sync: true,
-	}
 	err = lvl.db.Put(
 		[]byte(block.Hash[:]),
 		marshaled,
-		syncedOpt)
+		nil)
 	if err != nil {
 		return
 	}