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, 1 insertions, 0 deletions

diff --git a/integration_test/validator.go b/integration_test/validator.go
index fd7a7ad..2cb7e43 100644
--- a/integration_test/validator.go
+++ b/integration_test/validator.go
@@ -107,6 +107,7 @@ func (v *Validator) handleProposeBlock(when time.Time, piggyback interface{}) (
 	events []*test.Event, err error) {
 
 	b := &types.Block{ProposerID: v.ID}
+	defer types.RecycleBlock(b)
 	if err = v.cons.PrepareBlock(b, when); err != nil {
 		return
 	}