Re: [Qemu-devel] [PATCH v3 0/6] Add cache mode option to qemu-iotests, and change default mode to "writeback"

[Kevin Wolf <kwolf@redhat.com>]

Am 21.11.2013 um 13:43 hat Stefan Hajnoczi geschrieben:
> On Wed, Nov 20, 2013 at 03:44:11PM +0800, Fam Zheng wrote:
> > This series adds cache mode option in the iotests framework. Test cases are
> > updated to make use of cache mode and mask supported modes.
> > 
> > v3: Change _unsupported_qemu_io_options to _supported_cache_modes.
> >     Change default mode to "writeback".
> >     Clean up some whitespaces in the end of series.
> >     Fix "026.out.nocache" case.
> >     Fix 048 case on tmpfs.
> > 
> > 
> > Fam Zheng (6):
> >   qemu-iotests: Add "-c <cache-mode>" option
> >   qemu-iotests: Honour cache mode in iotests.py
> >   qemu-iotests: Add _supported_cache_modes
> >   qemu-iotests: Change default cache mode to "writeback"
> >   qemu-iotests: Force qcow2 in error path test in 048
> >   qemu-iotests: Clean up spaces in usage output
> > 
> >  tests/qemu-iotests/026        |  2 +-
> >  tests/qemu-iotests/039        |  2 +-
> >  tests/qemu-iotests/048        |  8 +++++++-
> >  tests/qemu-iotests/052        |  3 +--
> >  tests/qemu-iotests/check      |  2 +-
> >  tests/qemu-iotests/common     | 37 +++++++++++++++++++++++++++----------
> >  tests/qemu-iotests/common.rc  | 20 ++++++++++----------
> >  tests/qemu-iotests/iotests.py |  3 ++-
> >  8 files changed, 50 insertions(+), 27 deletions(-)
> 
> In principle I'm happy with the series but there are two instances where
> you are silently changing what the test does (overriding cache mode and
> image format).
> 
> Please skip tests that cannot run instead of silently testing something
> else.

Skipping isn't really a good solution either. For example, I almost
never test 039, because I always run ./check -nocache. What would be
most useful is to use a working cache mode for this test rather than
leaving it untested over weeks and months.

I mean we can make things as sophisticated as we want, and introduce a
list of cache modes in the order of their preference, so that I can say
./check -c none,writethrough, but that's probably a bit overengineered.

Kevin