perfSONAR User Q&A and Other Discussion

[Brian Candler <>]

On 10/12/2014 14:23, Aaron Brown wrote:
> Could you try applying this 
> patch:http://ndb1.internet2.edu/~aaron/bwctl_change_iperf3_exec.patch  (or 
> just downloadhttp://ndb1.internet2.edu/~aaron/iperf3.c  and replace the 
> iperf3.c in ‘bwlib’). This changes it so that bwctl just execs iperf3 instead 
> of linking to the library.
This one also doesn't give any output (see end of mail).

I know it's the patched daemon I'm running because it includes
bwctld[13564]: FILE=iperf3.c, LINE=65, Iperf3Available(): iperf3_cmd 
unset, using "iperf3"
in its startup message.

If I "strace -f" the parent bwctld process at the other side 
(cov-perf-1) I see:

# grep exec /var/tmp/bwctl.trace
[pid 55003] write(1, "bwctl: exec_line: iperf3 -c 212."..., 238) = 238
[pid 55003] execve("/sbin/iperf3", ["iperf3", "-c", "192.0.2.251", "-B", 
"192.0.2.254", "-f", "m", "-p", "5792", "-V", "-t", "10"], [/* 5 vars 
*/]) = -1 ENOENT (No such file or directory)
[pid 55003] execve("/usr/sbin/iperf3", ["iperf3", "-c", "192.0.2.251", 
"-B", "192.0.2.254", "-f", "m", "-p", "5792", "-V", "-t", "10"], [/* 5 
vars */]) = -1 ENOENT (No such file or directory)
[pid 55003] execve("/bin/iperf3", ["iperf3", "-c", "192.0.2.251", "-B", 
"192.0.2.254", "-f", "m", "-p", "5792", "-V", "-t", "10"], [/* 5 vars 
*/]) = -1 ENOENT (No such file or directory)
[pid 55003] execve("/usr/bin/iperf3", ["iperf3", "-c", "192.0.2.251", 
"-B", "192.0.2.254", "-f", "m", "-p", "5792", "-V", "-t", "10"], [/* 5 
vars */]) = 0
[pid 55006] execve("/bin/sh", ["sh", "-c", "uname -a"], [/* 5 vars */]) = 0
[pid 55006] execve("/bin/uname", ["uname", "-a"], [/* 5 vars */]) = 0
[pid 55002] write(13, ".254\nbwctl: exec", 16) = 16
[pid 55002] read(13, ".254\nbwctl: exec", 16) = 16
[pid 55001] write(10, ".254\nbwctl: exec", 16) = 16
[pid 55011] write(1, "bwctl: nothing to exec for trace"..., 199) = 199
[pid 55010] write(14, "ing to exec for ", 16) = 16

Grepping for process 55003 I see:

...
[pid 55003] socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 8
[pid 55003] bind(8, {sa_family=AF_INET, sin_port=htons(0), 
sin_addr=inet_addr("192.0.2.254")}, 16) = 0
[pid 55003] connect(8, {sa_family=AF_INET, sin_port=htons(5792), 
sin_addr=inet_addr("192.0.2.251")}, 16) = -1 ECONNREFUSED (Connection 
refused)
[pid 55003] close(8)                    = 0
[pid 55003] write(2, "iperf3: error - unable to connec"..., 64) = 64
[pid 55003] exit_group(1)               = ?

So it looks like the iperf3 -s simply isn't ready in time. Simple race 
condition? How much slack does bwctld allow between starting the server 
and starting the client?

Regards,

Brian.

[root@bou-perf-1
 ~]# time bwctl -v -x -a 2 -s cov-perf-1 -T iperf3
Messages being sent to syslog(user,err)
bwctl: Using cov-perf-1 as the address for remote sender
bwctl: Using 192.0.2.251 as the address for local receiver
bwctl: Available in-common: iperf nuttcp iperf3
bwctl: Using tool: iperf3
bwctl: Server 'localhost' accepted test request at time 1418246840.702620
bwctl: Client 'cov-perf-1' accepted test request at time 1418246840.702620
bwctl: 43 seconds until test results available

RECEIVER START
bwctl: start_endpoint: 3627235608.629568
bwctl: run_endpoint: receiver: 192.0.2.251
bwctl: run_endpoint: sender: 192.0.2.254
bwctl: exec_line: iperf3 -s -B 192.0.2.251 -f m -p 5792 -V
bwctl: run_tool: tester: iperf3
bwctl: run_tool: receiver: 192.0.2.251
bwctl: run_tool: sender: 192.0.2.254
bwctl: start_tool: 3627235625.162757
iperf 3.0.9
Linux bou-perf-1.network.example.com 
2.6.32-504.1.3.el6.aufs.web100.x86_64 #1 SMP Wed Nov 12 16:01:48 UTC 
2014 x86_64 x86_64 x86_64 GNU/Linux
iperf3: interrupt - the server has terminated
-----------------------------------------------------------
Server listening on 5792
-----------------------------------------------------------
bwctl: stop_tool: 3627235656.684916
bwctl: stop_endpoint: 3627235656.685499

RECEIVER END

SENDER START
bwctl: start_endpoint: 3627235608.676979
bwctl: run_endpoint: receiver: 192.0.2.251
bwctl: run_endpoint: sender: 192.0.2.254
bwctl: exec_line: iperf3 -c 192.0.2.251 -B 192.0.2.254 -f m -p 5792 -V -t 10
bwctl: run_tool: tester: iperf3
bwctl: run_tool: receiver: 192.0.2.251
bwctl: run_tool: sender: 192.0.2.254
bwctl: start_tool: 3627235640.703108
iperf 3.0.9
Linux cov-perf-1.network.example.com 
2.6.32-504.1.3.el6.aufs.web100.x86_64 #1 SMP Wed Nov 12 16:01:48 UTC 
2014 x86_64 x86_64 x86_64 GNU/Linux
iperf3: error - unable to connect to server: Connection refused
bwctl: stop_tool: 3627235640.728257
bwctl: stop_endpoint: 3627235656.735306

SENDER END

real    0m48.170s
user    0m0.002s
sys    0m0.004s
[root@bou-perf-1
 ~]#