[Linuxptp-users] Fw: “Resource temporarily unavailable” errors during flood ping test

[Mario M. <mar...@we...>]

Hallo Richard,

I observed following error message with a new GM Clock search during my flood ping test:
 
 ptp4l[23768.970]: recvmsg tx timestamp failed: Resource temporarily unavailable
 ptp4l[23768.975]: port 1: send delay request failed
 ptp4l[23768.975]: port 1: SLAVE to FAULTY on FAULT_DETECTED
 ptp4l[23784.059]: port 1: FAULTY to LISTENING on FAULT_CLEARED
 ptp4l[23784.414]: port 1: new foreign master 0050c2.fffe.c2dfc3-1
 ptp4l[23788.424]: selected best master clock 0050c2.fffe.c2dfc3
 ptp4l[23788.425]: port 1: LISTENING to UNCALIBRATED on RS_SLAVE
 ptp4l[23790.092]: port 1: minimum delay request interval 2^3
 ptp4l[23790.688]: master offset       -329 s2 adj  -13761 path delay       1626
 ptp4l[23790.708]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED
 
 flood ping test script:
 while true; do sudo ping -f -c 1000 -s $RANDOM <IP of PTP Module> ; done.
 
I have instrument the ptp4l code and I could see that a part of problem was a not correct error handling in the function sk_receive(). The recvmsg() returns sometime a EAGAIN and try-again variable was not increment.
I have changed this and now disappears this error message with GM Clock search during my flood ping test and it works all very well. 
 
 My code changes:
 --- a/sk.c	
 +++ b/sk.c	
 
  		}
  		if (errno == EINTR) {
  			try_again++;
 -		} else if (errno == EAGAIN) {
 +		} else if ((errno == EAGAIN ) || (errno == EWOULDBLOCK)) {
  			usleep(1);
 +			try_again++;
  		} else {
  			break;
  		}  
 
 
Do you have an idea why these EAGAIN errors occur? I cloud not find a reason for non-blocking.
 
 Best regards,
 Mario