I've been noticing that ControlPath parameter is always different when test_that runs ssh on my local invocation and it's very slow.

Is it supposed to be this way or is this something local that can be fixed?

$ test_that --board=kevin-arcnext --no-quickmerge kevin cheets_BlockOutboundNetworkTest
INFO:root:Identity added: /tmp/test_that_results_OjwiRQ/testing_rsa (/tmp/test_that_results_OjwiRQ/testing_rsa)
19:20:41 INFO | Skipping quickmerge step.
19:20:41 INFO | Re-running test_that script in /build/kevin-arcnext/usr/local/build/autotest copy of autotest.
INFO:root:Identity added: /tmp/test_that_results_KcOXhj/testing_rsa (/tmp/test_that_results_KcOXhj/testing_rsa)
19:20:42 INFO | Began logging to /tmp/test_that_results_KcOXhj
Adding labels [u'cros-version:ad_hoc_build', u'board:kevin-arcnext'] to host kevin
19:20:42 INFO | Fetching suite for job named cheets_BlockOutboundNetworkTest...
19:20:43 INFO | Parsed 3742 child test control files.
19:20:43 INFO | Scheduling suite for job named cheets_BlockOutboundNetworkTest...
19:20:43 INFO | ... scheduled 1 job(s).
19:20:43 INFO | 1 jobs in job queue
19:20:44 INFO | autoserv| Results placed in /tmp/test_that_results_KcOXhj/results-1-cheets_BlockOutboundNetworkTest
19:20:44 INFO | autoserv| Logged pid 377 to /tmp/test_that_results_KcOXhj/results-1-cheets_BlockOutboundNetworkTest/.autoserv_execute
19:20:44 INFO | autoserv| Starting new HTTP connection (1): metadata.google.internal
19:20:44 INFO | autoserv| Configuration file does not exist, ignoring: /etc/chrome-infra/ts-mon.json
19:20:44 INFO | autoserv| ts_mon monitoring is disabled because the endpoint provided is invalid or not supported:
19:20:44 INFO | autoserv| ts_mon was set up.
19:20:44 INFO | autoserv| I am PID 377
19:20:44 INFO | autoserv| Starting master ssh connection '/usr/bin/ssh -a -x -N -o ControlMaster=yes -o ControlPath=/tmp/_autotmp_JhK1Hcssh-master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22 kevin'
19:20:45 INFO | autoserv| Attempting to autodetect if host is of type CrosHost
19:20:45 INFO | autoserv| Master ssh connection to kevin is down.
19:20:45 INFO | autoserv| Starting master ssh connection '/usr/bin/ssh -a -x -N -o ControlMaster=yes -o ControlPath=/tmp/_autotmp_vg1JHIssh-master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22 kevin'
19:20:45 INFO | autoserv| Master ssh connection to kevin is down.
19:20:45 INFO | autoserv| Starting master ssh connection '/usr/bin/ssh -a -x -N -o ControlMaster=yes -o ControlPath=/tmp/_autotmp_aWQGrissh-master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22 kevin'
19:20:46 INFO | autoserv| Master ssh connection to kevin is down.
19:20:46 INFO | autoserv| Starting master ssh connection '/usr/bin/ssh -a -x -N -o ControlMaster=yes -o ControlPath=/tmp/_autotmp_ig87wAssh-master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22 kevin'
19:20:47 INFO | autoserv| ping failed: not collecting network stats
19:20:47 INFO | autoserv| Not checking if job_repo_url contains autotest packages on ['kevin']
19:20:47 INFO | autoserv| Processing control file
19:20:47 INFO | autoserv| Master ssh connection to kevin is down.
19:20:47 INFO | autoserv| Starting master ssh connection '/usr/bin/ssh -a -x -N -o ControlMaster=yes -o ControlPath=/tmp/_autotmp_LFC6Pjssh-master/socket -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o ServerAliveCountMax=3 -o ConnectionAttempts=4 -o Protocol=2 -l root -p 22 kevin'