During development of the simulation cross-compile framework, we saw a significant number of desynchronization errors when running the simulation. We also saw process memory usage increase. This page provides test results to quantify these issues and decide whether to issue a pull request for the cross-compilation work.

Based on these results, I plan to proceed with the pull request. However, I recommend the amd64-windows firmware be labeled experimental and that we solicit user feedback. I also plan to file a bug for the memory usage.

Test Runs

A simulation test run used a three-mote simulation, with two nodes one hop away from the RPL root. The link quality between each node to the root was set to a 1.0 PDR. Each test run lasted approximately six hours. We used the OpenVisualizer develop_SW-112 branch to run the simulation.

Guide to table columns:

Arch-OS, CPU Firmware architecture, and the Intel CPU architecture on which the test was run. Windows tests were run on Windows 7.
FW Branch Most tests run on the FW-177i branch of the kb2ma repository, but a couple of runs used the current openwsn-fw develop branch.
Elapsed ASN Difference between ASN at end vs. start of run, on RPL root.
Memory Consumed Process memory use as reported by Windows Task Manager or Linux pidstat. Top value is normalized on elapsed ASN.
Desync Errors Count of desynchronization errors reported in OpenVisualizer log. Top value is normalized on elapsed ASN.

Arch-OS, CPU	FW Branch	Elapsed ASN	Memory Consumed	Desync Errors
x86-windows, i3	FW-177	14.9M slots	132K slots/MiB 113 MiB	877K slots/error 17 errors
x86-windows, i3	develop	16.0M slots	133K slots/MiB 121 MiB	593K slots/error 27 errors
x86-windows, i7	FW-177	26.3M slots	199K slots/MiB 132 MiB	560K slots/error 47 errors
amd64-windows, i7	FW-177	27.7M slots	73.8K slots/MiB 375 MiB	577K slots/error 48 errors
amd64-windows, i7	FW-177	27.2M slots	73.9K slots/MiB 369 MiB	567K slots/error 48 errors
amd64-windows, i3	FW-177	15.7M slots	73.7K slots/MiB 214 MiB	563K slots/error 28 errors
amd64-linux, i5	FW-177	12.6M slots	68.6K slots/MiB 184 MiB	843K slots/error 15 errors
amd64-linux, i5	FW-177	10.5M slots	68.9K slots/MiB 152MiB	955K slots/error 11 errors
amd64-linux, i5	develop	10.5M slots	68.7K slots/MiB 153 MiB	501K slots/error 21 errors

The first run of amd64-windows on the i3 CPU failed after around four hours. When we observed the run after six hours, ASN was not increasing, but process memory was fluctuating within a few KB, and CPU usage was 0. There was no output on the terminal to indicate an error occurred.

Discussion

The x86-windows FW-177 firmware performed no worse than the develop firmware. The error rate on the amd64-windows was consistently at 500K - 600K slots/error, but some of the x86-windows and amd64-linux runs showed this same error rate.

There is clearly a memory leak in the OpenVisualizer process, regardless of the firmware used, architecture, or operating system.

It is surprising that the i5-based Linux simulations ran significantly slower than the i3-based Windows simulations.