User Guide

Contents

Profile KVM Kernel and User Space on the KVM System

Install the
VTune
Profiler
on the KVM system and configure your target for the KVM guest OS profiling.
For application analysis, you need to install the
Intel® VTune™
Profiler
directly on your guest OS.
VTune
Profiler
installation detects a virtual environment and disables sampling drivers installation to avoid system instability. When the product is installed, proceed with project configuration by specifying your application as an analysis target and selecting an analysis type:
This profiling type supports two usage modes:
Both profiling modes are applicable to cloud environments but introduce some limitations.

Guest OS (User App) Profiling Mode

In this mode, the
VTune
Profiler
supports user-mode sampling and tracing analysis types, Hotspots and Threading, for the applications running in the Launch or Attach mode. System-wide analysis is not supported.

Guest OS (Kernel and User Space) Profiling Mode

In this mode, the
VTune
Profiler
provides limited event-based collection options for the Hotspots and Microarchitecture Exploration analyses and requires additional host system configuration to virtualize PMU counters.
To enable event-based sampling analysis on the KVM system:
  1. From the host system, open the configuration settings for the virtual machine.
  2. Select the
    CPUs
    or
    Processor
    option on the left.
  3. Enter
    host-passthrough
    into the
    Model
    field to pass through the host CPU features without modifying the guest system.
  4. Click
    Apply
    to save the changes.
When you select a hardware event-based analysis type (for example, Microarchitecture Exploration), the
VTune
Profiler
automatically enables a driverless event-based sampling collection using the Linux Perf* tool. For this analysis, the
VTune
Profiler
collects only architectural events. See the Performance Monitoring Unit Sharing Guide for more details on the supported architectural events.

Limitations

  • User-mode sampling limitations:
    • Only Hotspots and Threading analyses are supported.
    • No system-wide analysis is available.
  • Hardware event-based sampling limitations:
    • Only Hotspots and limited Microarchitecture Exploration analyses are supported.
    • PEBS counters are not virtualized.
    • Uncore events are not available.
  • KVM modules and host system modules do not show up in the analysis result.
  • Data on the guest OS and your application modules show up as locally collected statistics with no
    [guest]
    markers.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804