Dynamically adjust sync RAM usage based on total RAM

Signed-off-by: Yilun <zyl.skysniper@gmail.com>

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/onsi/ginkgo v1.8.0 // indirect
 	github.com/onsi/gomega v1.5.0 // indirect
 	github.com/patrickmn/go-cache v2.1.0+incompatible
+	github.com/pbnjay/memory v0.0.0-20190104145345-974d429e7ae4
 	github.com/pborman/uuid v1.2.0
 	github.com/pkg/errors v0.8.1 // indirect
 	github.com/rdegges/go-ipify v0.0.0-20150526035502-2d94a6a86c40

go.sum

@@ -4,6 +4,7 @@ github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMo
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
+github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db h1:woRePGFeVFfLKN/pOkfl+p/TAqKOfFu+7KPlMVpok/w=
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
@@ -69,6 +70,8 @@ github.com/op/go-logging v0.0.0-20160315200505-970db520ece7 h1:lDH9UUVJtmYCjyT0C
 github.com/op/go-logging v0.0.0-20160315200505-970db520ece7/go.mod h1:HzydrMdWErDVzsI23lYNej1Htcns9BCg93Dk0bBINWk=
 github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
 github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
+github.com/pbnjay/memory v0.0.0-20190104145345-974d429e7ae4 h1:MfIUBZ1bz7TgvQLVa/yPJZOGeKEgs6eTKUjz3zB4B+U=
+github.com/pbnjay/memory v0.0.0-20190104145345-974d429e7ae4/go.mod h1:RMU2gJXhratVxBDTFeOdNhd540tG57lt9FIUV0YLvIQ=
 github.com/pborman/uuid v1.2.0 h1:J7Q5mO4ysT1dv8hyrUGHb9+ooztCXu1D8MY8DZYsu3g=
 github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 github.com/pkg/errors v0.0.0-20190227000051-27936f6d90f9/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
@@ -110,6 +113,7 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190502183928-7f726cade0ab/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190628185345-da137c7871d7 h1:rTIdg5QFRR7XCaK4LCjBiPbx8j4DQRpdYMnGn/bJUEU=
 golang.org/x/net v0.0.0-20190628185345-da137c7871d7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=

util/config/config.go

@@ -20,6 +20,7 @@ import (
 	"github.com/nknorg/nkn/crypto/ed25519/vrf"
 	"github.com/nknorg/nkn/crypto/util"
 	"github.com/nknorg/nnet/transport"
+	"github.com/pbnjay/memory"
 )
 
 const DefaultConfigFile = "config.json"
@@ -64,6 +65,7 @@ const (
 	GASAssetName                 = "New Network Coin"
 	GASAssetSymbol               = "nnc"
 	GASAssetPrecision            = uint32(8)
+	MaxSyncMemoryUsagePercent    = 10
 )
 
 var (
@@ -114,9 +116,9 @@ var (
 		MiningDebug:               true,
 		LogLevel:                  1,
 		MaxLogFileSize:            20,
-		SyncBatchWindowSize:       128,
+		SyncBatchWindowSize:       64,
 		SyncBlockHeadersBatchSize: 128,
-		SyncBlocksBatchSize:       8,
+		SyncBlocksBatchSize:       4,
 		RPCReadTimeout:            5,
 		RPCWriteTimeout:           10,
 		KeepAliveTimeout:          15,
@@ -178,6 +180,11 @@ type Configuration struct {
 }
 
 func Init() error {
+	syncBatchWindowSize := uint32(memory.TotalMemory()*MaxSyncMemoryUsagePercent/100/MaxBlockSize) / Parameters.SyncBlocksBatchSize
+	if syncBatchWindowSize > 0 {
+		Parameters.SyncBatchWindowSize = syncBatchWindowSize
+	}
+
 	configFile := ConfigFile
 	if configFile == "" {
 		configFile = DefaultConfigFile