2.3.1b4 (#1184)

Including changes to mnexec -c to reduce the number of
close() system calls, which may help with performance in
containers on Ubuntu 22.04.

Note that systemd-udevd also seems to be a cause of performance issues
and should probably be disabled while running Mininet.

Adding dbeug logging to test_simpleperf because it is failing
intermittently. (Note with packet loss it can fail, but this
is not how we should be testing it.)

INSTALL

@@ -2,7 +2,7 @@
 Mininet Installation/Configuration Notes
 ----------------------------------------
 
-Mininet 2.3.1b3
+Mininet 2.3.1b4
 ---
 
 The supported installation methods for Mininet are 1) using a

README.md

@@ -2,7 +2,7 @@ Mininet: Rapid Prototyping for Software Defined Networks
 ========================================================
 *The best way to emulate almost any network on your laptop!*
 
-Mininet 2.3.1b3
+Mininet 2.3.1b4
 
 [![Build Status][1]](https://github.com/mininet/mininet/actions)
 
@@ -70,7 +70,7 @@ Mininet includes:
 
 ### Python 3 Support
 
-- Mininet 2.3.1b3 supports Python 3 and Python 2
+- Mininet 2.3.1b4 supports Python 3 and Python 2
 
 - You can install both the Python 3 and Python 2 versions of
 Mininet side by side, but the most recent installation will

examples/simpleperf.py

@@ -49,13 +49,19 @@ def perfTest( lossy=True ):
     net.start()
     info( "Dumping host connections\n" )
     dumpNodeConnections(net.hosts)
-    info( "Testing bandwidth between h1 and h4\n" )
+    info( "Testing bandwidth between h1 and h4 (lossy=%s)\n" % lossy )
     h1, h4 = net.getNodeByName('h1', 'h4')
     net.iperf( ( h1, h4 ), l4Type='UDP' )
+    # Debugging
+    h1.cmd('jobs')
+    h4.cmd('jobs')
     net.stop()
 
 
 if __name__ == '__main__':
     setLogLevel( 'info' )
+    # Debug for now
+    if 'testmode' in argv:
+        setLogLevel( 'debug' )
     # Prevent test_simpleperf from failing due to packet loss
     perfTest( lossy=( 'testmode' not in argv ) )

examples/test/test_simpleperf.py

@@ -19,9 +19,12 @@ class testSimplePerf( unittest.TestCase ):
         # 10 Mb/s, plus or minus 20% tolerance
         BW = 10
         TOLERANCE = .2
-        p = pexpect.spawn( 'python -m mininet.examples.simpleperf testmode' )
+        p = pexpect.spawn(
+            'python -m mininet.examples.simpleperf testmode' )
+        # Log since this seems to be failing intermittently
+        p.logfile = sys.stdout
         # check iperf results
-        p.expect( "Results: \['10M', '([\d\.]+) .bits/sec", timeout=480 )
+        p.expect( "Results: \['10M', '([\d\.]+) .bits/sec", timeout=90 )
         measuredBw = float( p.match.group( 1 ) )
         lowerBound = BW * ( 1 - TOLERANCE )
         upperBound = BW + ( 1 + TOLERANCE )
@@ -30,5 +33,5 @@ class testSimplePerf( unittest.TestCase ):
         p.wait()
 
 if __name__ == '__main__':
-    setLogLevel( 'warning' )
+    setLogLevel( 'debug' )
     unittest.main()

mininet/net.py

@@ -109,7 +109,7 @@ from mininet.util import ( quietRun, fixLimits, numCores, ensureRoot,
 from mininet.term import cleanUpScreens, makeTerms
 
 # Mininet version: should be consistent with README and LICENSE
-VERSION = "2.3.1b3"
+VERSION = "2.3.1b4"
 
 class Mininet( object ):
     "Network emulation with hosts spawned in network namespaces."

mnexec.c

@@ -24,6 +24,9 @@
 #include <sched.h>
 #include <ctype.h>
 #include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
 
 #if !defined(VERSION)
 #define VERSION "(devel)"
@@ -96,18 +99,26 @@ int main(int argc, char *argv[])
 {
     int c;
     int fd;
+    DIR *dir;
+    struct dirent *de;
     char path[PATH_MAX];
     int nsid;
     int pid;
     char *cwd = get_current_dir_name();
-
     static struct sched_param sp;
+
     while ((c = getopt(argc, argv, "+cdnpa:g:r:vh")) != -1)
         switch(c) {
         case 'c':
             /* close file descriptors except stdin/out/error */
-            for (fd = getdtablesize(); fd > 2; fd--)
-                close(fd);
+            if ((dir = opendir("/proc/self/fd"))) {
+                while ((de = readdir(dir)))
+                    if ((fd = atoi(de->d_name)) > 2)
+                        close(fd);
+            }
+            /* fall back to old method if needed */
+            else for (fd = getdtablesize(); fd > 2; fd--)
+                     close(fd);
             break;
         case 'd':
             /* detach from tty */