Re: [Qemu-devel] [Qemu-block] [PATCH] qemu-iotests: Reduce racy output in 028

[Eric Blake <eblake@redhat.com>]

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On 12/11/2015 06:23 PM, John Snow wrote:
> 

ping

> 
> On 12/10/2015 10:27 PM, Eric Blake wrote:
>> On my machine, './check -qcow2 028' was failing about 80% of the
>> time, due to a race in how many times the repeated attempts
>> to run 'info block-jobs' could occur before the job was done,
>> showing up as a failure of fewer '(qemu) ' prompts than in the
>> expected output.  Silence the output during the repetitions, then
>> add a final clean command to keep the expected output useful;
>> once patched, I was finally able to run the test 20 times in a
>> row with no failures.
>>
> 
> Son of a gun:
> 
> 028 4s ... - output mismatch (see 028.out.bad)
> --- /home/bos/jsnow/src/q3mu/tests/qemu-iotests/028.out	2015-10-09
> 13:33:06.823758271 -0400
> +++ 028.out.bad	2015-12-11 20:12:23.688952510 -0500
> @@ -470,7 +470,7 @@
> 
>  Formatting 'TEST_DIR/t.IMGFMT.copy', fmt=IMGFMT size=4294968832
> backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
>  (qemu)
> -(qemu) info block-jobs
> +info block-jobs
>  Type backup, device disk: Completed 0 of 4294968832 bytes, speed limit
> 0 bytes/s
>  info block-jobs
>  No active jobs
> 
> 
> Something must have changed to make it more prone to races, somehow.
> Venus... Swamp gas...

Now that 2.6 is open, is my approach right, or do we need a more robust
solution?

> 
>> Signed-off-by: Eric Blake <eblake@redhat.com>
>> ---
>>
>> Not sure if this is the best fix, or if it is even appropriate
>> for inclusion in 2.5 this late in the game.
>>
>>  tests/qemu-iotests/028     | 6 ++++--
>>  tests/qemu-iotests/028.out | 3 ---
>>  2 files changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/tests/qemu-iotests/028 b/tests/qemu-iotests/028
>> index a1f4423..756c335 100755
>> --- a/tests/qemu-iotests/028
>> +++ b/tests/qemu-iotests/028
>> @@ -111,10 +111,12 @@ h=$QEMU_HANDLE
>>  QEMU_COMM_TIMEOUT=1
>>
>>  # Silence output since it contains the disk image path and QEMU's readline
>> -# character echoing makes it very hard to filter the output
>> +# character echoing makes it very hard to filter the output. Plus, there
>> +# is no telling how many times the command will repeat before succeeding.
>>  _send_qemu_cmd $h "drive_backup disk ${TEST_IMG}.copy" "(qemu)" >/dev/null
>>  _send_qemu_cmd $h "" "Formatting" | _filter_img_create
>> -qemu_cmd_repeat=20 _send_qemu_cmd $h "info block-jobs" "No active jobs"
>> +qemu_cmd_repeat=20 _send_qemu_cmd $h "info block-jobs" "No active jobs" >/dev/null
>> +_send_qemu_cmd $h "info block-jobs" "No active jobs"
>>  _send_qemu_cmd $h 'quit' ""
>>
>>  # Base image sectors
>> diff --git a/tests/qemu-iotests/028.out b/tests/qemu-iotests/028.out
>> index 29c9972..e03452d 100644
>> --- a/tests/qemu-iotests/028.out
>> +++ b/tests/qemu-iotests/028.out
>> @@ -469,10 +469,7 @@ No errors were found on the image.
>>  block-backup
>>
>>  Formatting 'TEST_DIR/t.IMGFMT.copy', fmt=IMGFMT size=4294968832 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
>> -(qemu)
>>  (qemu) i^[[K^[[Din^[[K^[[D^[[Dinf^[[K^[[D^[[D^[[Dinfo^[[K^[[D^[[D^[[D^[[Dinfo ^[[K^[[D^[[D^[[D^[[D^[[Dinfo b^[[K^[[D^[[D^[[D^[[D^[[D^[[Dinfo bl^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo blo^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo bloc^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-j^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-jo^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-job^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-jobs^[[K
>> -Type backup, device disk: Completed 0 of 4294968832 bytes, speed limit 0 bytes/s
>> -i^[[K^[[Din^[[K^[[D^[[Dinf^[[K^[[D^[[D^[[Dinfo^[[K^[[D^[[D^[[D^[[Dinfo ^[[K^[[D^[[D^[[D^[[D^[[Dinfo b^[[K^[[D^[[D^[[D^[[D^[[D^[[Dinfo bl^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo blo^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo bloc^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-j^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-jo^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-job^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block-jobs^[[K
>>  No active jobs
>>  === IO: pattern 195
>>  read 512/512 bytes at offset 3221194240
>>
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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