The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/66febb21b67946a92da22539caabdd1b32ad24e9

commit 66febb21b67946a92da22539caabdd1b32ad24e9
Author: Po-Hsien Wang <pwang@chromium.org>
Date: Tue Jun 06 05:07:26 2017

ssh_host.py: measurement of host.ssh times

Add the measurement of the host.run to have better understanding
about what is happending to the network ssh calls.

BUG= chromium:729161 
TEST=ran test_that graphics_Sanity

Result by logging inside metrics.SecondsTimer experimentally
06/05 15:33:38.153 DEBUG| ssh_host:0286| Running (ssh) '/bin/uname -r'
06/05 15:33:38.199 DEBUG|    utils:0298| [stdout] 4.4.44-07362-g31d7be5
06/05 15:33:38.200 DEBUG|  metrics:0253| ../master_ssh_time dt: 0.05

Change-Id: I09d5405f3c6823bd3122eadc78084a0f4f0dfd2a
Reviewed-on: https://chromium-review.googlesource.com/525016
Commit-Ready: Po-Hsien Wang <pwang@chromium.org>
Tested-by: Po-Hsien Wang <pwang@chromium.org>
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>

[modify] https://crrev.com/66febb21b67946a92da22539caabdd1b32ad24e9/server/hosts/ssh_host.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/c61365458055546f7793d34202fd3f4e36fb687c

commit c61365458055546f7793d34202fd3f4e36fb687c
Author: Po-Hsien Wang <pwang@chromium.org>
Date: Fri Sep 29 06:26:30 2017

ssh_hosts.py: set ssh time to report in milliseconds

1) Fix issue with the metrics.SecondsTimer so that it can
report time with millisecond-based metrics.
2) Remove unused import 'warnings'

BUG= chromium:729161 
TEST=unittest_suit

Change-Id: Iadbfa1d26ec64003cdd8df0642472e0a034b86e7
Reviewed-on: https://chromium-review.googlesource.com/600896
Commit-Ready: Po-Hsien Wang <pwang@chromium.org>
Tested-by: Po-Hsien Wang <pwang@chromium.org>
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>

[modify] https://crrev.com/c61365458055546f7793d34202fd3f4e36fb687c/server/hosts/ssh_host.py

http://shortn/_cBqq09F8C0 shows the statistics of the ssh time.

Nice! Unfortunately long term there is a worrying upward trend:
http://shortn/_pTFlnrSwLZ