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    <div class="moz-cite-prefix">If this is scheduler collapse, it would
      mean you have a port driver or NIF that has internal latency
      greater than 1 millisecond.  To handle scheduler collapse, you can
      use the erl command line option "-heart" combined with:<br>
      heart:set_options([check_schedulers]).<br>
      <br>
      (see <a class="moz-txt-link-freetext" href="http://erlang.org/doc/man/heart.html#set_options-1">http://erlang.org/doc/man/heart.html#set_options-1</a> )<br>
      <br>
      That will allow the system to restart when schedulers have
      collapsed.<br>
      <br>
      A test that is meant to cause scheduler collapse is at:<br>
      <a class="moz-txt-link-freetext" href="https://github.com/basho/nifwait">https://github.com/basho/nifwait</a><br>
      <br>
      So you could use that to prove to yourself that the behavior is
      the same with the system you are having problems with.<br>
      <br>
      <br>
      On 12/09/2016 08:35 AM, Matthew Evans wrote:<br>
    </div>
    <blockquote
cite="mid:MWHPR08MB260875E91FEB3B40C5F4BF7A9C870@MWHPR08MB2608.namprd08.prod.outlook.com"
      type="cite">
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        <p>Happened again, it appears that code_server is wedged:</p>
        <p><br>
        </p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
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          <span style="font-variant-ligatures: no-common-ligatures;">admin@plexxi:~$
            doErlangFun "erlang:process_info(whereis(code_server))."</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">[{registered_name,code_server},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {current_function,{code_server,cpc_recv,4}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {initial_call,{erlang,apply,2}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {status,waiting},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {message_queue_len,23},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {messages,[{code_call,<6805.4097.0>,{ensure_loaded,switch_type_module}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.4146.0>,{ensure_loaded,switch_type_module}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.941.0>,{ensure_loaded,pc_port_autoneg}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.541.0>,{ensure_loaded,plexxiStatistics_types}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.520.0>,{ensure_loaded,switch_type_module}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.5123.0>,{ensure_loaded,secondary_erlang_node}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.5122.0>,{ensure_loaded,secondary_erlang_node}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.5162.0>,{ensure_loaded,icmp}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                    {code_call,<6805.5321.0>,</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">  
                               
            {ensure_loaded,mac_entries_record_handler}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.5483.0>,{ensure_loaded,icmp}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.6647.0>,{ensure_loaded,icmp}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.7232.0>,{ensure_loaded,icmp}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.7274.0>,{ensure_loaded,icmp}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.7304.0>,{ensure_loaded,icmp}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                    {code_call,<6805.8889.0>,</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">  
                               
            {ensure_loaded,mac_entries_record_handler}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                    {code_call,<6805.8951.0>,</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">  
                               
            {ensure_loaded,mac_entries_record_handler}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                    {code_call,<6805.576.0>,</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">  
                               
            {ensure_loaded,cross_connect_unicast_utils}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.19300.12>,{ensure_loaded,shell}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.20313.12>,{ensure_loaded,shell}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
            {code_call,<6805.21339.12>,{ensure_loaded,dbg}},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                    {code_call,<6805.31109.13>,get_mode},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                    {code_call,<6805.1255.14>,get_mode},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                   
{system,{<6805.2521.14>,#Ref<6805.0.23.35356>},get_status}]},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {links,[<6805.11.0>]},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {dictionary,[{any_native_code_loaded,false}]},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {trap_exit,true},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {error_handler,error_handler},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {priority,normal},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {group_leader,<6805.9.0>},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {total_heap_size,86071},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {heap_size,10958},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {stack_size,25},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {reductions,13172282},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {garbage_collection,[{min_bin_vheap_size,46422},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                              {min_heap_size,233},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                              {fullsweep_after,65535},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;">   
                              {minor_gcs,71}]},</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
          line-height: normal; font-family: Menlo;">
          <span style="font-variant-ligatures: no-common-ligatures;"> {suspending,[]}]</span></p>
        <p style="margin: 0px; font-style: normal;
          font-variant-ligatures: normal; font-variant-caps: normal;
          font-weight: normal; font-stretch: normal; font-size: 11px;
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          <span style="font-variant-ligatures: no-common-ligatures;">admin@plexxi:~$ </span></p>
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          <div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
              face="Calibri, sans-serif" color="#000000"><b>From:</b>
              <a class="moz-txt-link-abbreviated" href="mailto:erlang-questions-bounces@erlang.org">erlang-questions-bounces@erlang.org</a>
              <a class="moz-txt-link-rfc2396E" href="mailto:erlang-questions-bounces@erlang.org"><erlang-questions-bounces@erlang.org></a> on behalf of
              Matthew Evans <a class="moz-txt-link-rfc2396E" href="mailto:mattevans123@hotmail.com"><mattevans123@hotmail.com></a><br>
              <b>Sent:</b> Friday, December 9, 2016 9:56 AM<br>
              <b>To:</b> Erlang/OTP discussions<br>
              <b>Subject:</b> [erlang-questions] R17 - Possible wedged
              scheduler</font>
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              <p>Hi,</p>
              <p><br>
              </p>
              <p>We just hit a situation where it appeared that 1
                scheduler was wedged. Some parts of our application were
                working, but others appeared to be stuck. I could
                connect via a cnode application and an escript, but I
                couldn't connect via the Erlang shell. We have an
                escript that does rpc calls, some worked, others (e.g.
                anything to the code server or tracing failed) failed. </p>
              <p><br>
              </p>
              <p>CPU load was minimal at the time, and heart didn't
                complain. We only have a single NIF, but this is not
                called on this hardware variant. We do use CNODE to talk
                to C applications.</p>
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              <p>We are running R17, Intel quad core CPU on Debian.</p>
              <p><br>
              </p>
              <p>This is the first time this has been seen, so the
                questions are:</p>
              <p><br>
              </p>
              <p>1. Has anyone seen this before?</p>
              <p>2. What can we do if we hit this condition in the
                future to debug?</p>
              <p>3. Since heart doesn't detect this can anyone think of
                any alternative mechanisms?</p>
              <p><br>
              </p>
              <p>Thanks</p>
              <p><br>
              </p>
              <p>Matt</p>
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      <pre wrap="">_______________________________________________
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