diff --git a/mempool/mempool.go b/mempool/mempool.go
index 0744880a1..46e71f4e8 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -77,6 +77,10 @@ func NewMempool(proxyAppConn proxy.AppConn) *Mempool {
 	return mempool
 }
 
+func (mem *Mempool) Size() int {
+	return mem.txs.Len()
+}
+
 // Return the first element of mem.txs for peer goroutines to call .NextWait() on.
 // Blocks until txs has elements.
 func (mem *Mempool) TxsFrontWait() *clist.CElement {
diff --git a/rpc/core/dev.go b/rpc/core/dev.go
new file mode 100644
index 000000000..a7a5c54df
--- /dev/null
+++ b/rpc/core/dev.go
@@ -0,0 +1,56 @@
+package core
+
+import (
+	"fmt"
+	"os"
+	"runtime/pprof"
+	"strconv"
+
+	ctypes "github.com/tendermint/tendermint/rpc/core/types"
+)
+
+func UnsafeSetConfig(typ, key, value string) (*ctypes.ResultUnsafeSetConfig, error) {
+	switch typ {
+	case "string":
+		config.Set(key, value)
+	case "int":
+		val, err := strconv.Atoi(value)
+		if err != nil {
+			return nil, fmt.Errorf("non-integer value found. key:%s; value:%s; err:%v", key, value, err)
+		}
+		config.Set(key, val)
+	case "bool":
+		switch value {
+		case "true":
+			config.Set(key, true)
+		case "false":
+			config.Set(key, false)
+		default:
+			return nil, fmt.Errorf("bool value must be true or false. got %s", value)
+		}
+	default:
+		return nil, fmt.Errorf("Unknown type %s", typ)
+	}
+	return &ctypes.ResultUnsafeSetConfig{}, nil
+}
+
+var profFile *os.File
+
+func UnsafeStartCPUProfiler(filename string) (*ctypes.ResultUnsafeCPUProfiler, error) {
+	var err error
+	profFile, err = os.Create(filename)
+	if err != nil {
+		return nil, err
+	}
+	err = pprof.StartCPUProfile(profFile)
+	if err != nil {
+		return nil, err
+	}
+	return &ctypes.ResultUnsafeCPUProfiler{}, nil
+}
+
+func UnsafeStopCPUProfiler() (*ctypes.ResultUnsafeCPUProfiler, error) {
+	pprof.StopCPUProfile()
+	profFile.Close()
+	return &ctypes.ResultUnsafeCPUProfiler{}, nil
+}
diff --git a/rpc/core/mempool.go b/rpc/core/mempool.go
index e10c72660..d06fca8b2 100644
--- a/rpc/core/mempool.go
+++ b/rpc/core/mempool.go
@@ -41,6 +41,5 @@ func UnconfirmedTxs() (*ctypes.ResultUnconfirmedTxs, error) {
 }
 
 func NumUnconfirmedTxs() (*ctypes.ResultUnconfirmedTxs, error) {
-	txs := mempoolReactor.Mempool.Reap()
-	return &ctypes.ResultUnconfirmedTxs{len(txs), txs[:0]}, nil
+	return &ctypes.ResultUnconfirmedTxs{N: mempoolReactor.Mempool.Size()}, nil
 }
diff --git a/rpc/core/routes.go b/rpc/core/routes.go
index 5a4987da5..b642ad7fe 100644
--- a/rpc/core/routes.go
+++ b/rpc/core/routes.go
@@ -24,7 +24,9 @@ var Routes = map[string]*rpc.RPCFunc{
 	"unconfirmed_txs":      rpc.NewRPCFunc(UnconfirmedTxsResult, ""),
 	"num_unconfirmed_txs":  rpc.NewRPCFunc(NumUnconfirmedTxsResult, ""),
 
-	"unsafe_set_config": rpc.NewRPCFunc(UnsafeSetConfigResult, "type,key,value"),
+	"unsafe_set_config":         rpc.NewRPCFunc(UnsafeSetConfigResult, "type,key,value"),
+	"unsafe_start_cpu_profiler": rpc.NewRPCFunc(UnsafeStartCPUProfilerResult, "filename"),
+	"unsafe_stop_cpu_profiler":  rpc.NewRPCFunc(UnsafeStopCPUProfilerResult, ""),
 }
 
 func SubscribeResult(wsCtx rpctypes.WSRPCContext, event string) (ctypes.TMResult, error) {
@@ -146,3 +148,19 @@ func UnsafeSetConfigResult(typ, key, value string) (ctypes.TMResult, error) {
 		return r, nil
 	}
 }
+
+func UnsafeStartCPUProfilerResult(filename string) (ctypes.TMResult, error) {
+	if r, err := UnsafeStartCPUProfiler(filename); err != nil {
+		return nil, err
+	} else {
+		return r, nil
+	}
+}
+
+func UnsafeStopCPUProfilerResult() (ctypes.TMResult, error) {
+	if r, err := UnsafeStopCPUProfiler(); err != nil {
+		return nil, err
+	} else {
+		return r, nil
+	}
+}
diff --git a/rpc/core/status.go b/rpc/core/status.go
index 8f056fd4e..bf3d69ffe 100644
--- a/rpc/core/status.go
+++ b/rpc/core/status.go
@@ -1,9 +1,6 @@
 package core
 
 import (
-	"fmt"
-	"strconv"
-
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
 	"github.com/tendermint/tendermint/types"
 )
@@ -31,28 +28,3 @@ func Status() (*ctypes.ResultStatus, error) {
 		LatestBlockHeight: latestHeight,
 		LatestBlockTime:   latestBlockTime}, nil
 }
-
-func UnsafeSetConfig(typ, key, value string) (*ctypes.ResultUnsafeSetConfig, error) {
-	switch typ {
-	case "string":
-		config.Set(key, value)
-	case "int":
-		val, err := strconv.Atoi(value)
-		if err != nil {
-			return nil, fmt.Errorf("non-integer value found. key:%s; value:%s; err:%v", key, value, err)
-		}
-		config.Set(key, val)
-	case "bool":
-		switch value {
-		case "true":
-			config.Set(key, true)
-		case "false":
-			config.Set(key, false)
-		default:
-			return nil, fmt.Errorf("bool value must be true or false. got %s", value)
-		}
-	default:
-		return nil, fmt.Errorf("Unknown type %s", typ)
-	}
-	return &ctypes.ResultUnsafeSetConfig{}, nil
-}
diff --git a/rpc/core/types/responses.go b/rpc/core/types/responses.go
index 660c6e0c1..ee7307a26 100644
--- a/rpc/core/types/responses.go
+++ b/rpc/core/types/responses.go
@@ -70,6 +70,8 @@ type ResultUnconfirmedTxs struct {
 
 type ResultUnsafeSetConfig struct{}
 
+type ResultUnsafeCPUProfiler struct{}
+
 type ResultSubscribe struct {
 }
 
@@ -109,7 +111,9 @@ const (
 	ResultTypeEvent       = byte(0x82)
 
 	// 0xa bytes for testing
-	ResultTypeUnsafeSetConfig = byte(0xa0)
+	ResultTypeUnsafeSetConfig        = byte(0xa0)
+	ResultTypeUnsafeStartCPUProfiler = byte(0xa1)
+	ResultTypeUnsafeStopCPUProfiler  = byte(0xa2)
 )
 
 type TMResult interface {
@@ -133,4 +137,6 @@ var _ = wire.RegisterInterface(
 	wire.ConcreteType{&ResultUnsubscribe{}, ResultTypeUnsubscribe},
 	wire.ConcreteType{&ResultEvent{}, ResultTypeEvent},
 	wire.ConcreteType{&ResultUnsafeSetConfig{}, ResultTypeUnsafeSetConfig},
+	wire.ConcreteType{&ResultUnsafeCPUProfiler{}, ResultTypeUnsafeStartCPUProfiler},
+	wire.ConcreteType{&ResultUnsafeCPUProfiler{}, ResultTypeUnsafeStopCPUProfiler},
 )