Performance measurements

README.md

@@ -15,6 +15,7 @@ vpncloud -c REMOTE_HOST:PORT --ifup 'ifconfig $IFNAME 10.0.0.1/24 mtu 1400 up'
 ```
 
 More details can be found in [the manpage](vpncloud.md).
+Some performance measurements can be found [here](performance.md).
 
 
 ### Current Status
@@ -31,6 +32,7 @@ However there are some open issues:
 * The protocol can still change.
 * The software is not very well tested.
 * The coverage score includes all unused methods from *libsodium*
+* The software has not been optimized for speed.
 
 Please feel free to help and contribute code.
 

performance.md

@@ -0,0 +1,91 @@
+Performance Tests
+-----------------
+
+### Test setup
+
+Two nodes with:
+  * 2x Intel(R) Xeon(R) CPU L5420
+  * 16 GiB Ram
+  * Intel Corporation 80003ES2LAN Gigabit Ethernet Controller (Kernel driver e1000e)
+  * Debian Linux 7.0 (Kernel 2.6.32-26-pve)
+  * Connected by Cisco Catalyst 4506 switch
+
+VpnCloud version: `VpnCloud v0.1.0 (without crypto support, protocol version 1)`
+
+
+### Test 1: Unencrypted throughput
+
+Node 1:
+```
+$> ./vpncloud -t tap -l NODE1:3210 -c NODE2:3210 \
+   --ifup 'ifconfig $IFNAME 10.2.1.1/24 mtu MTU up' &
+```
+
+Node 2:
+```
+$> ./vpncloud -t tap -l NODE2:3210 -c NODE1:3210 \
+   --ifup 'ifconfig $IFNAME 10.2.1.2/24 mtu MTU up' &
+$> iperf -s &
+$> top
+```
+
+First, the test is run **without VpnCloud**:
+```
+$> iperf -c NODE2 -t 60
+```
+
+and then **via VpnCloud**:
+```
+$> iperf -c 10.2.1.2 -t 60
+```
+
+**Results:**
+  * Throughput without VpnCloud: 938 Mbits/sec
+  * Throughput via VpnCloud (MTU=1400): 363 Mbits/sec
+  * CPU usage for VpnCloud (MTU=1400): maxed out at ~105% of one core
+  * Throughput via VpnCloud (MTU=16384): 946 Mbits/sec (no idea why this is higher)
+  * CPU usage for VpnCloud (MTU=16384): ~73% of one core
+
+
+### Test 2: Unencrypted ping
+
+Node 1:
+```
+$> ./vpncloud -t tap -l NODE1:3210 -c NODE2:3210 \
+   --ifup 'ifconfig $IFNAME 10.2.1.1/24 mtu 1400 up' &
+```
+
+Node 2:
+```
+$> ./vpncloud -t tap -l NODE2:3210 -c NODE1:3210 \
+   --ifup 'ifconfig $IFNAME 10.2.1.2/24 mtu 1400 up' &
+```
+
+Each test is first run without VpnCloud:
+```
+$> ping NODE2 -c 1000 -i 0.01 -s SIZE -U -q
+```
+
+and then with VpnCloud:
+```
+$> ping 10.2.1.2 -c 1000 -i 0.01 -s SIZE -U -q
+```
+
+SIZE: 50 bytes
+  * Without VpnCloud: Ø= 200 µs, stddev= 28 µs
+  * With VpnCloud: Ø= 318 µs, stddev= 26 µs
+
+SIZE: 500 bytes
+  * Without VpnCloud: Ø= 235 µs, stddev= 29 µs
+  * With VpnCloud: Ø= 351 µs, stddev= 26 µs
+
+SIZE: 1400 bytes
+  * Without VpnCloud: Ø= 303 µs, stddev= 32 µs
+  * With VpnCloud: Ø= 421 µs, stddev= 31 µs
+
+
+### Conclusion
+
+* VpnCloud achieves about 360 MBit/s with default MTU settings.
+* At increased MTU, VpnCloud is able to saturate a Gigabit link.
+* VpnCloud adds about 120µs to the round trip times, i.e. 60µs latency increase.

src/ethernet.rs

@@ -58,12 +58,13 @@ struct SwitchTableValue {
 
 pub struct SwitchTable {
     table: HashMap<Address, SwitchTableValue>,
+    cache: Option<(Address, SocketAddr)>,
     timeout: Duration
 }
 
 impl SwitchTable {
     pub fn new(timeout: Duration) -> Self {
-        SwitchTable{table: HashMap::new(), timeout: timeout}
+        SwitchTable{table: HashMap::new(), cache: None, timeout: timeout}
     }
 }
 
@@ -80,6 +81,7 @@ impl Table for SwitchTable {
             info!("Forgot address {:?}", key);
             self.table.remove(&key);
         }
+        self.cache = None;
     }
 
     fn learn(&mut self, key: Address, _prefix_len: Option<u8>, addr: SocketAddr) {
@@ -89,7 +91,7 @@ impl Table for SwitchTable {
         }
     }
 
-    fn lookup(&self, key: &Address) -> Option<SocketAddr> {
+    fn lookup(&mut self, key: &Address) -> Option<SocketAddr> {
         match self.table.get(key) {
             Some(value) => Some(value.address),
             None => None

src/ip.rs

@@ -63,7 +63,7 @@ impl Table for RoutingTable {
         }
     }
 
-    fn lookup(&self, addr: &Address) -> Option<SocketAddr> {
+    fn lookup(&mut self, addr: &Address) -> Option<SocketAddr> {
         let len = addr.0.len()/2 * 2;
         for i in 0..(len/2)+1 {
             if let Some(group) = self.0.get(&addr.0[0..len-2*i]) {

src/types.rs

@@ -122,7 +122,7 @@ impl fmt::Display for Mode {
 
 pub trait Table {
     fn learn(&mut self, Address, Option<u8>, SocketAddr);
-    fn lookup(&self, &Address) -> Option<SocketAddr>;
+    fn lookup(&mut self, &Address) -> Option<SocketAddr>;
     fn housekeep(&mut self);
     fn remove_all(&mut self, SocketAddr);
 }