Errol can you test VM timer with utility https://rt.wiki.kernel.org/index.php/Cyclictest

My VM currently have folowing results

[root@fs1 ~]#  date && /tmp/rt-tests/cyclictest -t42 -p 80 -d 0 -n -i 125 -l 240000 && date
Sun Apr  5 07:01:31 GMT 2015
# /dev/cpu_dma_latency set to 0us
policy: fifo: loadavg: 2.38 0.93 0.50 1/194 1574           

T: 0 ( 1531) P:80 I:125 C: 240000 Min:      2 Act:   12 Avg:   16 Max:    1302
T: 1 ( 1532) P:80 I:125 C: 240000 Min:      2 Act:   15 Avg:   14 Max:    2895
T: 2 ( 1533) P:80 I:125 C: 240000 Min:      3 Act:   10 Avg:   12 Max:    2888
T: 3 ( 1534) P:80 I:125 C: 240000 Min:      1 Act:   16 Avg:   13 Max:    1333
T: 4 ( 1535) P:80 I:125 C: 240000 Min:      2 Act:   20 Avg:   14 Max:    2962
T: 5 ( 1536) P:80 I:125 C: 240000 Min:      1 Act:   12 Avg:   14 Max:    2946
T: 6 ( 1537) P:80 I:125 C: 240000 Min:      2 Act:   10 Avg:   13 Max:    1363
T: 7 ( 1538) P:80 I:125 C: 240000 Min:      2 Act:   12 Avg:   13 Max:    1344
T: 8 ( 1539) P:80 I:125 C: 240000 Min:      3 Act:   12 Avg:   16 Max:    1408
T: 9 ( 1540) P:80 I:125 C: 240000 Min:      1 Act:    8 Avg:   13 Max:    2882
T:10 ( 1541) P:80 I:125 C: 239974 Min:      2 Act:   12 Avg:   13 Max:    2908

On Mon, Apr 6, 2015 at 11:15 AM, Errol Samuels <ewsamuels@gmail.com> wrote:

Good job and Thanks for sharing!

KVM at digitalocean.com, Debian 7 64bit, FreeSWITCH 1.4.15: bad precision

 

As someone who has been using KVM for a few years and has just migrated about 20 VMs across to Digital Ocean about 6 weeks ago I admit I am a little concerned about this finding.

Just out of curiosity can you tell me the specs of the VM that you tested with and which DO Datacenter?  I am using NYC3 so perhaps and I will do some tests as soon as I have some time.

With regards to Xen was this at Linode or inhouse?

Thanks

Errol

On Sun, Apr 5, 2015 at 1:37 AM, Stanislav Sinyagin <ssinyagin@gmail.com> wrote:

here we go:
https://txlab.wordpress.com/2015/04/05/testing-rtp-clock-precision-on-a-virtual-machine/

On Sat, Apr 4, 2015 at 4:26 PM, Stanislav Sinyagin <ssinyagin@gmail.com> wrote:
> On Sat, Apr 4, 2015 at 1:03 PM, Regis M <regis.freeswitch.org@tornad.net> wrote:
>> How do you check wavs together in audacity ?
>
> you just open two WAV files, align their starting position, and
> visually check the waves. If there's a problem, you would see that
> after few seconds, the waves are not aligned any more.
>
>> Can you send me 2 samples wav (send... and recorded) so I could see the 20ms
>> diff that you exposed...
>>
>> Is there a way to automate the result checking, so it could help to monitor
>> itsp quality
>
> Here
> https://github.com/openpreserve/scape-xcorrsound/issues/17
> this is a link to a tool which compares two sound files at the wave
> level. You can also see the sound samples in the ticket.
> The problem is, that currently this tool does not detect such slipping frames.
>
> I will also write a detailed article with examples, during the weekend.
>
>
>
>
>
>>
>>
>> 2015-04-04 12:53 GMT+02:00 Stanislav Sinyagin <ssinyagin@gmail.com>:
>>>
>>> Important is to send the media through two independent carriers - then you
>>> can be sure that your clock is compared against a high quality one.
>>>
>>> On Apr 4, 2015 12:46 PM, "Regis M" <regis.freeswitch.org@tornad.net>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> It's a very interresting test and conclusion.
>>>>
>>>> I will try to build a similar environnement on my freeswitch to check
>>>> some system :)
>>>>
>>>> thanks
>>>>
>>>>
>>>>
>>>> 2015-04-04 2:16 GMT+02:00 Stanislav Sinyagin <ssinyagin@gmail.com>:
>>>>>
>>>>> hi,
>>>>>
>>>>> Here are some test results which might be interesting:
>>>>>
>>>>> I've set up a test FreeSWITCH server at digitalocean (they use KVM),
>>>>> and originated test calls to some ITSP accounts. Each call played a
>>>>> test sound file (voice samples from ITU:
>>>>> http://www.itu.int/net/itu-t/sigdb/genaudio/AudioForm-g.aspx?val=1000050
>>>>> ), and on the receiving end another FreeSWITCH server was recording
>>>>> the received session. The receiving server was on a XEN VM. Both
>>>>> servers talked G711 to their corresponding ITSP accounts.
>>>>>
>>>>> Then I compared the source audio and received audio in Audacity editor.
>>>>>
>>>>> The tests showed that the received voice wave shifts 20ms from the
>>>>> original sound every few seconds, randomly back and forward. This
>>>>> skewing was always present, regardless of ITSP and time of day.
>>>>>
>>>>> Then I moved the sending server to a XEN VM, and the waves appeared
>>>>> almost perfectly synchronized (there was a 5ms skew in one test, and I
>>>>> guess it's related to transcoding buffer, as the sound was obviously
>>>>> transcoded).
>>>>>
>>>>> The effect was always visible with a 30-second sample, and I also made
>>>>> additional tests with 2-minute samples.
>>>>>
>>>>> It would also be interesting to test this from a VmWare VM. If someone
>>>>> wants to run such a test, feel free to contact me directly.
>>>>>
>>>>>
>>>>> cheers,
>>>>> stan
>>>>>
>>>>>
>>>>> _________________________________________________________________________
>>>>> Professional FreeSWITCH Consulting Services:
>>>>> consulting@freeswitch.org
>>>>> http://www.freeswitchsolutions.com
>>>>>
>>>>> Official FreeSWITCH Sites
>>>>> http://www.freeswitch.org
>>>>> http://confluence.freeswitch.org
>>>>> http://www.cluecon.com
>>>>>
>>>>> FreeSWITCH-users mailing list
>>>>> FreeSWITCH-users@lists.freeswitch.org
>>>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>>>>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>>>>> http://www.freeswitch.org
>>>>
>>>>
>>>>
>>>> _________________________________________________________________________
>>>> Professional FreeSWITCH Consulting Services:
>>>> consulting@freeswitch.org
>>>> http://www.freeswitchsolutions.com
>>>>
>>>> Official FreeSWITCH Sites
>>>> http://www.freeswitch.org
>>>> http://confluence.freeswitch.org
>>>> http://www.cluecon.com
>>>>
>>>> FreeSWITCH-users mailing list
>>>> FreeSWITCH-users@lists.freeswitch.org
>>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>>>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>>>> http://www.freeswitch.org
>>>
>>>
>>> _________________________________________________________________________
>>> Professional FreeSWITCH Consulting Services:
>>> consulting@freeswitch.org
>>> http://www.freeswitchsolutions.com
>>>
>>> Official FreeSWITCH Sites
>>> http://www.freeswitch.org
>>> http://confluence.freeswitch.org
>>> http://www.cluecon.com
>>>
>>> FreeSWITCH-users mailing list
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>>> http://www.freeswitch.org
>>
>>
>>
>> _________________________________________________________________________
>> Professional FreeSWITCH Consulting Services:
>> consulting@freeswitch.org
>> http://www.freeswitchsolutions.com
>>
>> Official FreeSWITCH Sites
>> http://www.freeswitch.org
>> http://confluence.freeswitch.org
>> http://www.cluecon.com
>>
>> FreeSWITCH-users mailing list
>> FreeSWITCH-users@lists.freeswitch.org
>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>> http://www.freeswitch.org

_________________________________________________________________________
Professional FreeSWITCH Consulting Services:
consulting@freeswitch.org
http://www.freeswitchsolutions.com

Official FreeSWITCH Sites
http://www.freeswitch.org
http://confluence.freeswitch.org
http://www.cluecon.com

FreeSWITCH-users mailing list
FreeSWITCH-users@lists.freeswitch.org
http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
http://www.freeswitch.org

_________________________________________________________________________
Professional FreeSWITCH Consulting Services:
consulting@freeswitch.org
http://www.freeswitchsolutions.com

Official FreeSWITCH Sites
http://www.freeswitch.org
http://confluence.freeswitch.org
http://www.cluecon.com

FreeSWITCH-users mailing list
FreeSWITCH-users@lists.freeswitch.org
http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
http://www.freeswitch.org

_________________________________________________________________________
Professional FreeSWITCH Consulting Services:
consulting@freeswitch.org
http://www.freeswitchsolutions.com

Official FreeSWITCH Sites
http://www.freeswitch.org
http://confluence.freeswitch.org
http://www.cluecon.com

FreeSWITCH-users mailing list
FreeSWITCH-users@lists.freeswitch.org
http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
http://www.freeswitch.org