perfSONAR User Q&A and Other Discussion

[Brian Candler <>]

I made little headway in narrowing this down.

I added some debugging in bwctl.c wait_for_results. When the total test 
times were ~45 seconds, I was able to see that the difference between 
the req_time and the current time was 35 seconds (but duration=10, 
omit=0, fuzz=just over 1 second). So it's something to do with 
calculating the future request time.

I have also seen cases of wait_for_results saying times of over 80 seconds.

I then added further debugging, but by the time I did this, it was back 
to "working" again - 15 seconds per test :-(

At bwctl client side:

bwctl: BWLGetTimeStamp: errest=2100000
bwctl: BWLSetTimeStampError: val=9019431321
bwctl: BWLSetTimeStampError: scale=26, multiplier=135
bwctl: BWLGetTimeStamp: errest=2100000
bwctl: BWLSetTimeStampError: val=9019431321
bwctl: BWLSetTimeStampError: scale=26, multiplier=135

That's fine: 0.1 is the default skew estimate, and I put -a 2 on the 
command line.

On bwctld:

bwctld[16642]: FILE=time.c, LINE=395, BWLGetTimeStamp: errest=100000
bwctld[16642]: FILE=time.c, LINE=718, BWLSetTimeStampError: val=429496729
bwctld[16642]: FILE=time.c, LINE=736, BWLSetTimeStampError: scale=21, 
multiplier=205
bwctld[16642]: FILE=time.c, LINE=395, BWLGetTimeStamp: errest=100000
bwctld[16642]: FILE=time.c, LINE=718, BWLSetTimeStampError: val=429496729
bwctld[16642]: FILE=time.c, LINE=736, BWLSetTimeStampError: scale=21, 
multiplier=205

This is all fine. 429496729.0/(1<<32) ~= 0.1 seconds.

I can only guess that in some circumstances large fuzz or offset values 
are being used, but fiddling with BWCTL_DEBUG_TIMEOFFSET I am not able 
to recreate the problem.

Unfortunately I'm running out of time now as (a) it's late, and (b) 
tomorrow these boxes get shipped out :-(

Regards,

Brian.