Re: [Qemu-devel] [for-4.2 PATCH 0/6] Block-related record/replay fixes

["Alex Bennée" <alex.bennee@linaro.org>]

Pavel Dovgalyuk <dovgaluk@ispras.ru> writes:

>> -----Original Message-----
>> From: Alex Bennée [mailto:alex.bennee@linaro.org]
>> Sent: Tuesday, September 17, 2019 10:02 PM
>> To: Pavel Dovgalyuk
>> Cc: qemu-devel@nongnu.org; kwolf@redhat.com; peter.maydell@linaro.org;
>> crosthwaite.peter@gmail.com; boost.lists@gmail.com; artem.k.pisarenko@gmail.com;
>> quintela@redhat.com; ciro.santilli@gmail.com; jasowang@redhat.com; mst@redhat.com;
>> armbru@redhat.com; mreitz@redhat.com; maria.klimushenkova@ispras.ru; dovgaluk@ispras.ru;
>> kraxel@redhat.com; pavel.dovgaluk@ispras.ru; thomas.dullien@googlemail.com;
>> pbonzini@redhat.com; dgilbert@redhat.com; rth@twiddle.net
>> Subject: Re: [for-4.2 PATCH 0/6] Block-related record/replay fixes
>>
>>
>> Pavel Dovgalyuk <pavel.dovgaluk@gmail.com> writes:
>>
>> > The set of patches include the block-related updates
>> > of the record/replay icount feature:
>> >  - application of 'snapshot' option on the file layer instead of
>> >    the top one: command line and documentation fix
>> >  - implementation of bdrv_snapshot_goto for blkreplay driver
>> >  - start/stop fix in replay mode with attached block devices
>> >  - record/replay of bh oneshot events, used in the block layer
>>
>> Can we come up with a reasonable smoke test to verify record/replay is
>> functional? AIUI we don't need a full OS but we do need a block device
>> to store the replay data. Could we use one of the simple system tests
>> like "memory" and run that through a record and replay cycle?
>
> That's would be great.
> I'm not familiar with testing framework and couldn't find "memory"
> test that you refer to.

The memory test code is in tests/tcg/multiarch/system and gets combined
with the boot code for whichever target can build it. For example on
aarch64 it is run like:

  timeout 15  $BLD/aarch64-softmmu/qemu-system-aarch64 -monitor none -display none -chardev file,path=memory.out,id=output  -M virt -cpu max -display none -semihosting-config enable=on,target=native,chardev=output -kernel memory

The test binaries will be in $BLD/tests/tcg/aarch64-softmmu and are
built when you run "make check-tcg" and have either the appropriate
cross compilers installed on your system or docker enabled and setup
(see docs/devel/testing.rst).

> Replay test must at least the following:
> 1. record some execution
> 2. replay that execution
>
> And there could be several endings:
> 1. record stalled
> 2. record crashed
> 3. replay stalled
> 4. replay crashed
> 5. all executions finished successfully

If you can provide an appropriate set of invocations I can plumb them
into the Makefiles for you.

>
> Pavel Dovgalyuk
>
>>
>> >
>> > ---
>> >
>> > Pavel Dovgaluk (6):
>> >       block: implement bdrv_snapshot_goto for blkreplay
>> >       replay: disable default snapshot for record/replay
>> >       replay: update docs for record/replay with block devices
>> >       replay: don't drain/flush bdrv queue while RR is working
>> >       replay: finish record/replay before closing the disks
>> >       replay: add BH oneshot event for block layer
>> >
>> >
>> >  block/blkreplay.c        |    8 ++++++++
>> >  block/block-backend.c    |    9 ++++++---
>> >  block/io.c               |   32 ++++++++++++++++++++++++++++++--
>> >  block/iscsi.c            |    5 +++--
>> >  block/nfs.c              |    6 ++++--
>> >  block/null.c             |    4 +++-
>> >  block/nvme.c             |    6 ++++--
>> >  block/rbd.c              |    5 +++--
>> >  block/vxhs.c             |    5 +++--
>> >  cpus.c                   |    2 --
>> >  docs/replay.txt          |   12 +++++++++---
>> >  include/sysemu/replay.h  |    4 ++++
>> >  replay/replay-events.c   |   16 ++++++++++++++++
>> >  replay/replay-internal.h |    1 +
>> >  replay/replay.c          |    2 ++
>> >  stubs/Makefile.objs      |    1 +
>> >  stubs/replay-user.c      |    9 +++++++++
>> >  vl.c                     |   11 +++++++++--
>> >  18 files changed, 115 insertions(+), 23 deletions(-)
>> >  create mode 100644 stubs/replay-user.c
>>
>>
>> --
>> Alex Bennée


--
Alex Bennée