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Enable SACK in runsc 

SACK is disabled by default and needs to be manually enabled. It not only
improves performance, but also fixes hangs downloading files from certain
websites.

PiperOrigin-RevId: 207906742
Change-Id: I4fb7277b67bfdf83ac8195f1b9c38265a0d51e8b
This commit is contained in:
Fabricio Voznika 2018-08-08 10:24:53 -07:00 committed by Shentubot
parent cb23232c37
commit 0d350aac7f
3 changed files with 19 additions and 7 deletions
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6
pkg/sentry/socket/hostinet/stack.go
View File

@ -84,11 +84,13 @@ func (s *Stack) Configure() error {
log.Warningf("Failed to read TCP send buffer size, using default values")
}
s.tcpSACKEnabled = false
// SACK is important for performance and even compatibility, assume it's
// enabled if we can't find the actual value.
s.tcpSACKEnabled = true
if sack, err := ioutil.ReadFile("/proc/sys/net/ipv4/tcp_sack"); err == nil {
s.tcpSACKEnabled = strings.TrimSpace(string(sack)) != "0"
} else {
log.Warningf("Failed to read if TCP SACK if enabled, setting to false")
log.Warningf("Failed to read if TCP SACK if enabled, setting to true")
}
return nil

5
runsc/boot/controller.go
View File

@ -285,7 +285,10 @@ func (cm *containerManager) Restore(o *RestoreOpts, _ *struct{}) error {
fs.SetRestoreEnvironment(*renv)
// Prepare to load from the state file.
networkStack := newEmptyNetworkStack(cm.l.conf, k)
networkStack, err := newEmptyNetworkStack(cm.l.conf, k)
if err != nil {
return fmt.Errorf("failed to create network: %v", err)
}
info, err := o.FilePayload.Files[0].Stat()
if err != nil {
return err

15
runsc/boot/loader.go
View File

@ -174,7 +174,10 @@ func New(spec *specs.Spec, conf *Config, controllerFD int, ioFDs []int, console
// this point. Netns is configured before Run() is called. Netstack is
// configured using a control uRPC message. Host network is configured inside
// Run().
networkStack := newEmptyNetworkStack(conf, k)
networkStack, err := newEmptyNetworkStack(conf, k)
if err != nil {
return nil, fmt.Errorf("failed to create network: %v", err)
}
// Initiate the Kernel object, which is required by the Context passed
// to createVFS in order to mount (among other things) procfs.
@ -525,16 +528,20 @@ func (l *Loader) WaitExit() kernel.ExitStatus {
return l.k.GlobalInit().ExitStatus()
}
func newEmptyNetworkStack(conf *Config, clock tcpip.Clock) inet.Stack {
func newEmptyNetworkStack(conf *Config, clock tcpip.Clock) (inet.Stack, error) {
switch conf.Network {
case NetworkHost:
return hostinet.NewStack()
return hostinet.NewStack(), nil
case NetworkNone, NetworkSandbox:
// NetworkNone sets up loopback using netstack.
netProtos := []string{ipv4.ProtocolName, ipv6.ProtocolName, arp.ProtocolName}
protoNames := []string{tcp.ProtocolName, udp.ProtocolName, ping.ProtocolName4}
return &epsocket.Stack{stack.New(netProtos, protoNames, stack.Options{Clock: clock})}
s := &epsocket.Stack{stack.New(netProtos, protoNames, stack.Options{Clock: clock})}
if err := s.Stack.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.SACKEnabled(true)); err != nil {
return nil, fmt.Errorf("failed to enable SACK: %v", err)
}
return s, nil
default:
panic(fmt.Sprintf("invalid network configuration: %v", conf.Network))