The build machine used for this tryjob is a GCE, which supports only some perf events. The perf events used in the quipper unitests are not supported by the GCE kernel so quipper unittests fail.

Below are the perf commands used by the failing quipper unittests and the output of the commands.

$ sudo perf stat -a -e cycles -e instructions -e branches -e branch-misses -v -- sleep 0.2
Using CPUID GenuineIntel-6-3F
Warning:
cycles event is not supported by the kernel.
Warning:
instructions event is not supported by the kernel.
Warning:
branches event is not supported by the kernel.
Warning:
branch-misses event is not supported by the kernel.
failed to read counter cycles
failed to read counter instructions
failed to read counter branches
failed to read counter branch-misses

 Performance counter stats for 'system wide':

   <not supported>      cycles                                                      
   <not supported>      instructions                                                
   <not supported>      branches                                                    
   <not supported>      branch-misses                                               

       0.200934993 seconds time elapsed

$ sudo perf stat -a -e cycles -v -- sleep 0.2
Using CPUID GenuineIntel-6-3F
Warning:
cycles event is not supported by the kernel.
failed to read counter cycles

 Performance counter stats for 'system wide':

   <not supported>      cycles                                                      

       0.201322494 seconds time elapsed

Pre-cq passed with the latest quipper ebuild file at cl 971584.

https://cros-goldeneye.corp.google.com/chromeos/healthmonitoring/buildDetails?buildbucketId=8951399406564882352

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/03e7f5ead3d7ae68ede329b2dad7ad7da9baf6ef

commit 03e7f5ead3d7ae68ede329b2dad7ad7da9baf6ef
Author: Lakshman Annadorai <lakshmana@chromium.org>
Date: Fri Mar 23 21:50:52 2018

Pull the latest changes from github.

Update ebuild to match the new directory structure in github.

BUG= chromium:824399 
TEST=tested with emerge-<board> using the updated ebuild

Change-Id: I6ba137abebb551ab02932726d73111e9315cf36d
Reviewed-on: https://chromium-review.googlesource.com/971584
Commit-Ready: Lakshman Annadorai <lakshmana@chromium.org>
Tested-by: Lakshman Annadorai <lakshmana@chromium.org>
Reviewed-by: Lakshman Annadorai <lakshmana@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[modify] https://crrev.com/03e7f5ead3d7ae68ede329b2dad7ad7da9baf6ef/chromeos-base/quipper/Manifest
[modify] https://crrev.com/03e7f5ead3d7ae68ede329b2dad7ad7da9baf6ef/chromeos-base/quipper/files/quipper-disable-flaky-tests.patch
[modify] https://crrev.com/03e7f5ead3d7ae68ede329b2dad7ad7da9baf6ef/chromeos-base/quipper/quipper-9999.ebuild