[kvm-unit-tests PATCH v6 0/1] s390x: Add exit time test

[Nico Boehr <nrb@linux.ibm.com>]

v5->v6:
---
* multiply first, then divide when normalizing (thanks Claudio)
* print fractions of us (thanks Claudio)
* remove non-normalized output (thanks Claudio)
* fence dag9c since not supported under TCG

v4->v5:
---
* print normalized runtime to be able to compare runtime of
  instructions in a single run (thanks Claudio)

v3->v4:
---
* remove merge conflict markers (thanks Christian)

v2->v3:
---
* print average (thanks Claudio)
* have asm constraints look the same everywhere (thanks Claudio)
* rebase patchset on top of my migration sck patches[1] to make use of the
  time.h improvements

v1->v2:
---
* add missing cc clobber, fix constraints for get_clock_us() (thanks
  Thomas)
* avoid array and use pointer to const char* (thanks Thomas)
* add comment why testing nop makes sense (thanks Thomas)
* rework constraints and clobbers (thanks Thomas)

Sometimes, it is useful to measure the exit time of certain instructions
to e.g. identify performance regressions in instructions emulated by the
hypervisor.

This series adds a test which executes some instructions and measures
their execution time. Since their execution time depends a lot on the
environment at hand, all tests are reported as PASS currently.

The point of this series is not so much the instructions which have been
chosen here (but your ideas are welcome), but rather the general
question whether it makes sense to have a test like this in
kvm-unit-tests.

This series is based on my migration sck patches[1] to make use of the
time.h improvements there.

[1] https://lore.kernel.org/all/20221011170024.972135-1-nrb@linux.ibm.com/

Nico Boehr (1):
  s390x: add exittime tests

 s390x/Makefile      |   1 +
 s390x/exittime.c    | 296 ++++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg |   4 +
 3 files changed, 301 insertions(+)
 create mode 100644 s390x/exittime.c

-- 
2.36.1