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    <div dir="auto">I am using CentOS 6, kernel 3.10 from elrepo.org
      kernels (3.10.102-1.el6.elrepo.x86_64).<br>
      Asterisk version is 11.21.2 and Asterisk 13.X.X (I can't get it's
      version now).<br>
      <br>
      Is it possible that your network switches' interfaces which are
      connected to Hyper-V Server are 100% busy?<br>
      It is possible that my installation works well because my Hyper-V
      server is not high-load server so it has plenty free CPU, Disk,
      Memory, Network resources to give them to Asterisk VM.<br>
      <br>
      Kseniya, could you try to reserve 100% of virtual CPUs for
      Asterisk VM (just to test this configuration)?<br>
      <br>
      <br>
      I am sorry I don't have free hardware and time to test your Ubuntu
      16, asterisk 13.1, kernel 4.4.0-104 configuration(<br>
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    <div class="gmail_extra"><br>
      <div class="gmail_quote">On 18 Dec 2017 12:09 p.m., "Kseniya
        Blashchuk" <<a href="mailto:ksyblast@gmail.com">ksyblast@gmail.com</a>>
        wrote:<br type="attribution">
        <blockquote class="gmail_quote" style="margin:0 0 0
          .8ex;border-left:1px #ccc solid;padding-left:1ex">
          <div dir="ltr">Dmitry, are you using CentOS? What kernel
            version are you using? I will try with the same to see if it
            can be also a kernel-related issue.</div>
          <br>
          <div class="gmail_quote">
            <div dir="ltr">пн, 18 дек. 2017 г. в 11:35, Kseniya
              Blashchuk <<a href="mailto:ksyblast@gmail.com"
                target="_blank">ksyblast@gmail.com</a>>:<br>
            </div>
            <blockquote class="gmail_quote" style="margin:0 0 0
              .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div dir="ltr">Thank you for a quick answer, Dmitry!
                <div><br>
                </div>
                <div>We have tried the settings you suggested but
                  nothing helped. The machine is running 4.4.0-104
                  kernel, 4 cores, Intel(R) Xeon(R) CPU E5-2620 v3 @
                  2.40GHz, clocksource is hyperv_clocksource_tsc_<wbr>page,
                  timing module is res_timing_timerfd.so. We have also
                  tried to set 50% Reserve - no luck :(. </div>
              </div>
              <br>
              <div class="gmail_quote">
                <div dir="ltr">пн, 18 дек. 2017 г. в 10:49, Dmitriy
                  Ermakov <<a href="mailto:demonihin@gmail.com"
                    target="_blank">demonihin@gmail.com</a>>:<br>
                </div>
              </div>
              <div class="gmail_quote">
                <blockquote class="gmail_quote" style="margin:0 0 0
                  .8ex;border-left:1px #ccc solid;padding-left:1ex">
                  <div text="#000000" bgcolor="#FFFFFF">
                    <p>Hi, Kseniya!</p>
                    <p>I have three installations of Asterisk (as
                      FreePBX but I think it is not important). They
                      work fine.</p>
                    <p>I have made some settings in Asterisk and
                      Hyper-V:</p>
                    <p>Asterisk: timing interface - timerfd.</p>
                    <p>Hyper-V:</p>
                    <ol>
                      <li>Virtual Machine => Network Adapter =>
                        Hardware Acceleration => Virtual Machine
                        Queue - Disable it;</li>
                      <li>Virtual Machine => Processor => Virtual
                        Machine Reserve (percentage) - set at least 25%
                        (if you have 4 virtual cores for your Asterisk).
                        You can try to set reserve more or less then 25%
                        - test it and, please, send email here;</li>
                      <li>Virtual Machine => Integration Services
                        => Time synchronisation - enable it.<br>
                      </li>
                    </ol>
                    <p> This settings helped me.</p>
                    <p>Also check your Linux Kernel version - it must be
                      3.10 or newer. I saw very bad "timing test"
                      results on kernel 2.6.32.<br>
                    </p>
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                  <div text="#000000" bgcolor="#FFFFFF"> <br>
                    <div
class="m_1043956196575610213m_8749962311671695405m_-6849995180857981132moz-cite-prefix">On
                      12/18/2017 10:26 AM, Kseniya Blashchuk wrote:<br>
                    </div>
                    <blockquote type="cite">
                      <div dir="ltr">Hi all!
                        <div>Does anybody have experience with asterisk
                          on Hyper-V? My test setup with Ubuntu 16 and
                          asterisk 13.1 (ubuntu repo) shows sound
                          distortion. I have analyzed the RTP flow with
                          wireshark and I see high skew and delta values
                          when the traffic leaves the hypervisor,
                          however everything is okay when a capture is
                          taken from a VM itself. I have read that there
                          can be timing problems with Hyper-V. I have
                          tried to disable time sync with the machine
                          and tried different clocksources. I have also
                          tried to change asterisk timing interface to
                          dahdi (dummy) - nothing helped so far. Hyper-V
                          version is 12p2.</div>
                        <div>Does anybody have a working setup with
                          Hyper-V?</div>
                        <div><br>
                        </div>
                      </div>
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                    <pre class="m_1043956196575610213m_8749962311671695405m_-6849995180857981132moz-signature" cols="72">-- 
С уважением, Дмитрий Ермаков</pre>
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                  Check out the new Asterisk community forum at: <a
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            href="https://community.asterisk.org/" rel="noreferrer"
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