Intel® VTune™ Profiler User Guide

User Guide

Contents

Profile Targets on a KVM* Guest System

Configure the
Intel® VTune™
Profiler
 to analyze performance on a KVM guest system.
Performance analysis for the host and virtual machine(s) in cloud environments helps identify such issues as resource contention (for example, CPU/vCPU time) and network/IO activity.
VTune
Profiler
 uses Perf*-based driverless collection to enable performance analysis of the guest Linux* operating system via Kernel-based Virtual Machine (KVM) from the host system.
Unlike other virtual machine systems, systems using KVM on a Linux* host to access a Linux guest can have
VTune
Profiler
 installed on either the host system to analyze performance on the guest system or installed directly on the guest system to analyze the guest system. Additional information about installing
VTune
Profiler
 is available from the Linux installation guides.
Depending on your analysis target, you may choose any of the supported usage modes for KVM guest OS profiling.

Profiling Modes

Currently, the
VTune
Profiler
 supports the following usage modes for KVM guest OS profiling, and each of them has some limitations:
Profiling System
KVM Guest OS (User Apps)
KVM Guest OS (User and Kernel Space)
Host and KVM Guest OS (User and Kernel Space)
(preview feature)
Supported analysis
User-mode sampling: Hotspots and Threading
Event-based sampling: Hotspots and limited Microarchitecture Exploration
Event-based sampling: all types with accurate attribution of user-space activity to the user processes on the guest
Target type
Applications in the Launch and Attach modes
  • Applications in the Launch and Attach modes
  • System-wide analysis
System-wide analysis (host and guest OS)
VTune
Profiler
 installation mode
On the guest OS
On the guest OS
On the host and guest OS (
VTune
Profiler
 custom collector)
Limitations
No system-wide analysis for user-mode sampling
  • Limited event-based sampling analysis due to a limited set of virtualized PMU events and unavailable uncore events
  • No information from the host
  • Additional debugfs and custom collector configuration is required
  • Access to the host system running VM is required
  • Not applicable to cloud environments
Configuration
PMU event virtualization required for Event-based sampling
Analyze KVM guest OS
 option

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