Thanks Steven Watanabe for the answer.

We are running the tests by directly calling b2 in a local wrapper, rather than calling run.py.
So, does that make sense for us to just upload the test logs using run.py?

I tried the following command, it says "Uploading log archive ... to master". But I did not see my test results on the summary page after several hours.
BinCaoWR.zip was manually created which only includes the attached log file.

$ python run.py --runner=BinCaoWR --toolsets=clang-vxworks-4.0.1 --tag=master --platform=vxWorks --comment=comment.html  upload-logs
# Running regressions in /opt/boost/Logs/boost_simics_nightly/20190421200812/any/xlnx_zynqmp_platform_smp/j32.xlnx_zynqmp_xlnxzcu102_default.true.llvm.vsbdir.lp64smp...
# Creating regression scripts at /opt/boost/Logs/boost_simics_nightly/20190421200812/any/xlnx_zynqmp_platform_smp/j32.xlnx_zynqmp_xlnxzcu102_default.true.llvm.vsbdir.lp64smp/boost_regression_src...
# Downloading regression scripts from https://raw.githubusercontent.com/boostorg/regression/develop/testing/src...
# Uploading log archive "/opt/boost/Logs/boost_simics_nightly/20190421200812/any/xlnx_zynqmp_platform_smp/j32.xlnx_zynqmp_xlnxzcu102_default.true.llvm.vsbdir.lp64smp/results/BinCaoWR.zip" to master

Is there anything wrong in my command, or any restriction on the test log format/content, etc?