Cygwin Error : tcp_peer_send_blocking: send() to socket - cygwin

Question

My Cygwin installed on Windows 7 was working properly till I try to install a new package. The package installation failed. Then I keep getting this error every time I want to run my Open MPI program. I can successfully compile the program but cannot run it. I even remove and make a new installation without success.
Thanks for any hints. Below is the sample error message.
[Reloaded-PC:03900] [[3921,1],0] tcp_peer_send_blocking: send() to socket 13 failed: Transport endpoint is not connected (128)
[Reloaded-PC:03900] [[3921,1],0] tcp_peer_send_blocking: send() to socket 13 failed: Transport endpoint is not connected (128)
[Reloaded-PC:04676] [[3921,1],2] tcp_peer_send_blocking: send() to socket 13 failed: Transport endpoint is not connected (128)
[Reloaded-PC:04676] [[3921,1],2] tcp_peer_send_blocking: send() to socket 13 failed: Transport endpoint is not connected (128)

Answer 1

The problem is solved by disabling the unused network adapter in "Control Panel->Network and Internet->Network Connections".
It turned out the unused network adapter tried to get configured by DHCP and an IP address started with "169.254.X.X" was assigned to this adapter when DHCP fails. Somehow openmpi on Cygwin use that invalid IP address for establishing communication between processes.
I figured it out by looking at /tmp/openmpi-sessions-{username}/{PID of orterun}/contact.txt.

Answer 2

I had this same problem on Cygwin with OpenMPI 1.10.4.
Try adding "-report-uri -" to your mpirun command to see what IP address it's trying to use for connection:
mpirun -report-uri - -np 2 a.exe
It should print out a line that looks something like this:
568328192.0;tcp://192.168.10.103,169.254.247.11,0.0.0.0,0.0.0.0,0.0.0.0:55600
If the first IP address after the "tcp://" is not a current valid address for your machine, that's the problem and things are likely to break (even if the correct IP appears later in the list). Apparently ORTE is not smart enough to order the interfaces based on what is actually enabled and online.
If the wrong IP corresponds to an old/disabled interface, uninstall it (if possible) using the windows network connections control panel.
In my case, the first address was a DHCP address for an old hardware adapter I'd removed and thrown away long ago (but apparently not uninstalled in software). Windows normally hides such removed-but-not-uninstalled interfaces in the control panel, but the settings remain in the registry under:
HKLM\SYSTEM\CurrentControlSet\services\Tcpip\Parameters\Interfaces\
Search in that registry subkey for the bogus IP address and you are likely to find the problematic interface. I fixed mine by changing the IP address in that registry key to match my current static IP, but uninstalling the interface entirely would probably also work.

Answer 3

I had the same problem with openmpi v 1.8.8 (which is the default version of the package installed by cygwin). Manually going back to version 1.8.6 fixed the issue for me.

Answer 4

I just encountered this problem and in my case I had to disable the "VirtualBox Host-Only Network" adapter (I recently installed virtualbox and have not used openmpi in cygwin after that until today).

Answer 5

1. Open the Cygwin terminal.
mpicc --version
mpirun --version
If not execute, follow the document below and reinstall everything. Document
2. Try turning off Bluetooth and test your program again.
3. Try closing the Wifi and test your program again (you can connect to the wired internete)
4. Open C:\Windows\System32\drivers\etc\hosts
add line
127.0.0.1 localhost cygdrive wpad
and test your program again.
5. If you have a virtual network like VirtualBox or similar, turn off the control panel and test your program again.
6. If possible, uninstall VirtualBox completely. Restart your computer and test your program again.
7. Try turning off the Windows Firewall and test your program again.
The above steps solved both the "tcp_peer_send_blocking: send () to socket 12 failed: transport endpoint is not connected" error and the slowness problem in MPI for Windows 10 - Cygwin.