how to remove timing errors

[Em Claire]

I am trying to do a test run on remote mode on tests/linux/connect/http-get-nonblocking-ts-mod.pkt

and I am seeing this:

1. error handling packet: timing error: expected outbound packet at 1.000433 sec but happened at 0.800374 sec

so I added + on one of the timing.

2. now I am getting another timing error: expected outbound packet at 0.20000 sec but happened at 0.300592 sec.

if i change the script to have it at 0.300, it would say it expected outbound packet at 0.500

--> how can we remove timing errors for the runs?

Thanks.

 

[Shivansh Rai]

Instead of using Relative timing model, you can use Relative-Range timing model to specify the relative time range after the last event in which the current event should occur.

Say for example, in your case, you can use something like this -

+0.0~+0.6 > P. 1:1001(1000) ack 1001

This will specify that the inbound packet should arrive within a time interval of 0.6 seconds from the previous event.

Regards,
Shivansh

[Shivansh Rai]

One more way in which you can remove these errors while testing is by using the --tolerace_usecs flag. You can use this flag to specify the tolerance in timing of your inbound packets in microseconds. This proves to be an effective way when you are testing and don't want to update the scripts to match the expected behavior as I mentioned in the previous answer.  

On Thursday, May 26, 2016 at 7:14:18 AM UTC+5:30, Em Claire wrote:

[Neal Cardwell]

Thanks for sharing these tips with the list. Let me clarify that the
--tolerace_usecs flag is most usefully thought of as specifying the
tolerance for the timing of outbound packets and system call returns.

The --tolerace_usecs flag is described in the Usenix paper and Usenix
login article:

Usenix paper:
https://www.usenix.org/system/files/conference/atc13/atc13-cardwell.pdf

Usenix login article:
https://www.usenix.org/system/files/login/articles/10_cardwell-online.pdf

neal

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[Shivansh Rai]

I apologize for my mistake as I have mistakenly written --tolerace_usecs, which got carried to the next answer and am noticing just now. The correct flag is --tolerance_usecs, in case someone gets confused.

Thanks.