TASS Belgium / Mbed 2 deprecated lwip_MEM_Test

lwip memory and full speed throughput test.

Dependencies:   EthernetInterface mbed-rtos mbed

This project represents a throughtput test for the EthernetInterface, based on the lwIP library.

The purpose of this is to be able to make a comparison of full speed (Rx,Tx and Rx+Tx) and memory between the EthernetInterface based on the lwIP and the one based on PicoTCP.

The benchmark consists of three parts:

• we are sending 1 Megabyte from the board to host
• we are waiting for the host to send us 1 Megabyte of data
• on the last part we are using a TCP Echo Server to send and receive back 1 Megabyte of data

we send/receive 1024 packets of 1024 bytes each and we measure how many bits per second we transmit and receive.

The result:
TX+RX Throughput: 4194304 bytes in 41 seconds (0.774) Mbits/s

Memory report
Current free memory : 22644 bytes
Maximum free memory : 24716 bytes
Minimum free memory : 22644 bytes
Average free memory : 22644 bytes

The python script used

#!/usr/bin/python
import sys, socket
import random, string
import select
from time import time
#ECHO_SERVER_ADDRESS = "10.20.30.139"
ECHO_SERVER_ADDRESS = "192.168.100.12"
ECHO_SERVER_PORT = 7
N_PACKETS = 1024
LEN_PACKET = 1024

TOT_BITS = (LEN_PACKET * N_PACKETS * 8) * 4. # TX bits + RX bits
PACKET = ''.join(random.choice(string.ascii_uppercase+string.digits) for _ in range(LEN_PACKET))
MEGA = 1024 * 1024.
UPDATE_STEP = (N_PACKETS/20) # Make the update step such as one step = 5%
UPDATE_R_STEP = (N_PACKETS/20) #Make the update step such as one step = 1%
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((ECHO_SERVER_ADDRESS, ECHO_SERVER_PORT))
start = time()
rx_total = 0
tx_total = 0
data = ''
i = 0
lp = []
p = select.poll()
while(True): # keeping this in for robustness testing, when the test will run for days
	#Stage I - sending data from host towards mbed board	
	print "Started sending data...."
	while (i < N_PACKETS):
	  p.register(s, select.POLLOUT)
	  lp = p.poll(1)
	  if (len(lp) > 0):
	    s.sendall(PACKET)
	    i+=1
	    if (i % UPDATE_STEP) == 0: print "sent %d/%d (%.2f%%)" % (i, N_PACKETS, float(i)/ float(N_PACKETS) * 100.)
	    continue

	#Stage II - receving data from the mbed board
	print "Started receiving data...."
	while(len(data) < N_PACKETS * LEN_PACKET):	
		p.register(s, select.POLLIN)
		lp = p.poll(1)
		if(len(lp) > 0):
		    r = s.recv(LEN_PACKET)
		    if (r != ''):
		      data += r
		      if (len(data) / LEN_PACKET) % UPDATE_R_STEP: print "recvd %d/%d (%.2f%%)" % (len(data)/LEN_PACKET, N_PACKETS, float(len(data))/ float(N_PACKETS * LEN_PACKET) * 100.)
		    else:
		      print "Error receiving !"
		      sys.exit(1)

	#Stage III - echo between host and mbed board
	print "Started echoing data...."
	for i in range(N_PACKETS):
		if (i % UPDATE_STEP) == 0: print "%.2f%%" % (float(i)/float(N_PACKETS) * 100.)
		s.sendall(PACKET)
		data = s.recv(LEN_PACKET)
		if (len(data) != LEN_PACKET):
			print "Error echoing !"
			sys.exit(1)

	print "Test was finished!"
	break;	

t = time() - start
s.close()
print "TX+RX Throughput: %d bytes in %d seconds (%.3f)Mbits/s" % (TOT_BITS / 8, t, ((TOT_BITS / t) / MEGA))

This test is based on the following libraries

Click here to see the results for PicoTCP

--- a/main.cpp	Mon Jul 08 12:25:13 2013 +0000
+++ b/main.cpp	Tue Jul 09 08:34:28 2013 +0000
@@ -7,6 +7,7 @@
 
 struct MemoryUsage
 {
+    uint32_t curFreeRam;
     uint32_t minFreeRam;
     uint32_t maxFreeRam;
     uint32_t avgFreeRam;
@@ -14,7 +15,7 @@
     uint32_t cntSamples;
 };
 
-struct MemoryUsage memoryStats = {0xFFFFFFFF,0,0,0};
+struct MemoryUsage memoryStats = {0,0xFFFFFFFF,0,0,0};
 
 int fakePrintf(void* pvHeapInfo, char const* pFormatString, ...)
 {
@@ -26,7 +27,7 @@
     {
         va_start(valist, pFormatString);
         unsigned long freeSize = va_arg(valist, unsigned long);
-        
+        memStat->curFreeRam = freeSize;
         if(memStat->minFreeRam > freeSize)
             memStat->minFreeRam = freeSize;
         
@@ -42,6 +43,21 @@
     return 0;
 }
 
+void inline printMemoryStats(void)
+{
+    if(memoryStats.cntSamples == 1)
+        printf("\n\n***** Initial Memory Report *****\n");
+    else
+        printf("\n\n********* Memory Report *********\n");
+    
+    printf("Current free memory : %d bytes\n",memoryStats.curFreeRam);
+    printf("Maximum free memory : %d bytes\n",memoryStats.maxFreeRam);
+    printf("Minimum free memory : %d bytes\n",memoryStats.minFreeRam);
+    printf("Average free memory : %d bytes\n",memoryStats.avgFreeRam);
+    printf("Stack pointer address : %d\n",memoryStats.stackPointer);
+    printf("****************************\n");
+}
+
 void inline memoryStamp(void)
 {
     __heapstats((__heapprt)fakePrintf, &memoryStats);
@@ -55,7 +71,12 @@
 int main() {
     
     printf("Ethernet Interface memory test....\n");
+    
+    // Initial memory status
+    memoryStamp();
     stackPtrSnapshot(); // snapshot of the stack pointer before starting benchmark to see the SP.
+    printMemoryStats();
+    
     EthernetInterface eth;
     int connections = 0;
     eth.init(); //Use DHCP
@@ -150,16 +171,16 @@
         if((dataReceived+dataSent) < 2*BUFFER_QUANTITY)
         {
             printf("Echo test has failed.Exiting connection...\n");
-            break;
         }
         else
         {
             printf("Echo test has passed...\n");
         }
+        break;
      }
     client.close();
-    printf("Memory report after connection....\n");
-    printf("Max memory : %d bytes\nMin memory : %d bytes\nAverage memory : %d\n",memoryStats.maxFreeRam,memoryStats.minFreeRam,memoryStats.avgFreeRam);
+    printf("Test was finished...\n");
+    printMemoryStats();
   }
   
   return 0;