https://community.intel.com/t5/Software-Tuning-Performance/Where-exactly-is-overflow-OVF-detected/m-p/1167510#M7200 <P>Hi, I am often getting overflow (OVF) packets from Intel PT on a small Goldmont Plus processor, and I'm wondering <STRONG>exactly what is overflowing</STRONG>. Is it some kind of on-chip buffer, or is it the RAM allocation that was configured by the operating system to receive the PT packets? It would be great to have a diagram that gives a precise overview of the&nbsp;dataflow stages for tracing on&nbsp;Linux via perf_event_open().&nbsp;Here's my setup:</P><UL><LI>Mini PC<UL><LI>CPU model Gemini Lake</LI><LI>8GB RAM</LI></UL></LI><LI>Fedora 29</LI><LI>decoding via Intel libipt&nbsp;(pt_packet_decoder only)</LI></UL><P>I also get overflows on my Xeon and i7 machines when running larger benchmarks, such as the SPEC 2017 reference data sets. <STRONG>Is there anything I can do to improve the reliability</STRONG> <STRONG>of the tracing</STRONG>, or is it simply subject to overflow on occasion? Thanks for your help.</P><P>Byron</P> Tue, 18 Jun 2019 09:05:20 GMT Hawkins__Byron 2019-06-18T09:05:20Z https://community.intel.com/t5/Software-Tuning-Performance/Where-exactly-is-overflow-OVF-detected/m-p/1167510#M7200 <P>Hi, I am often getting overflow (OVF) packets from Intel PT on a small Goldmont Plus processor, and I'm wondering <STRONG>exactly what is overflowing</STRONG>. Is it some kind of on-chip buffer, or is it the RAM allocation that was configured by the operating system to receive the PT packets? It would be great to have a diagram that gives a precise overview of the&nbsp;dataflow stages for tracing on&nbsp;Linux via perf_event_open().&nbsp;Here's my setup:</P><UL><LI>Mini PC<UL><LI>CPU model Gemini Lake</LI><LI>8GB RAM</LI></UL></LI><LI>Fedora 29</LI><LI>decoding via Intel libipt&nbsp;(pt_packet_decoder only)</LI></UL><P>I also get overflows on my Xeon and i7 machines when running larger benchmarks, such as the SPEC 2017 reference data sets. <STRONG>Is there anything I can do to improve the reliability</STRONG> <STRONG>of the tracing</STRONG>, or is it simply subject to overflow on occasion? Thanks for your help.</P><P>Byron</P> Tue, 18 Jun 2019 09:05:20 GMT https://community.intel.com/t5/Software-Tuning-Performance/Where-exactly-is-overflow-OVF-detected/m-p/1167510#M7200 Hawkins__Byron 2019-06-18T09:05:20Z