Beyond the Hypervisor Hype

Michael A. Salsburg, Ph.DUnisys

Outline

• Introduction to Hypervisors

• A Performance Comparison of Hypervisors

• It’s the I/O (again)

• Future Directions for Virtualized I/O

• Capacity Planning for transforming from Physical to Virtual

• Virtualization and Utility Computing

• Virtualization and Carrier-Level Service

• Virtualization Benchmarks

Introduction to Hypervisors

• Hypervisor executes directly on hardware (no OS)

• VMM presents itself to the virtual machine as the hardware

• Less code for hypervisor implies higher resiliency– Xen implements DOM0

• Xen paravirtualizes – VMware does not

A Performance Comparison of Hypervisors

• VMware and Xen publish different results with the same benchmarks

• Benchmarks– SPECcpu2000 Integer tests – CPU intensive

– Passmark – memory –intensive

– Netperf – network specific

– SPECjbb2005 – java application server workload

– SPECcpu2000 compilation tests – compilation benchmark for assessing development workloads

A Performance Comparison of Hypervisors

VMware Xen Results XenSource Xen Results

http://www.vmware.com/pdf/hypervisor_performance.pdf http://blogs.xensource.com/rogerk/wp-content/uploads/2007/03/hypervisor_performance_comparison_1_0_5_with_esx-data.pdf

REALITY Check

I/O transfers at “wire speed” does not tell the whole story……

An I/O-intensive workload can result in twice the CPU utilization on a virtual machine when compared to the physical one

It’s the I/O (again)

• Hypervisor emulation of a device– Discovery

– Device Control

– Data Transfer

– I/O Interrupts

• Pure Emulation– Support for Legacy O/S and

device drivers

• Performance Impact

It’s the I/O (again)

• Paravirtualization of Device Drivers are an essential element in good performance

• The replacement of the native device drivers is an essential part of virtualization– Physical to Virtual

Transformation

Future Directions for Virtualized I/OIntel Processors

No Virtualization

Future Directions for Virtualized I/O

Current Hypervisors

Future Directions for Virtualized I/O

• Intel’s VT-d provides Protection Domains– Protects Direct Memory

Access (DMA) between device and VM

• Interrupt remapping architecture

• Supports caching of remapping-structure entries on the device

VMMs with VT-d

Capacity Planning for transforming from Physical to Virtual

Capacity Planning for transforming from Physical to Virtual

Virtualization and Utility Computing

• “No More Down Time”

• Corporate workloads grow and shrink on shared resources– When resources are scarce, new servers are provisioned

– Otherwise, business policies dictate priorities for utility-wide CPU cycles

• What will it take for Business Units to share resources?

• Chargeback in a Virtualized Environment

• Real Time Infrastructure

Ticket Sales Scenario

.. using a real time infrastructure

Digital Dashboard

Ticketing Process

TicketRequest

BE

GIN

EN

D

EstablishSpecialNeeds

TicketReserved

SearchLoyalty

Program

PickLocation

CreditCard

Verification

IssueTicket

ReserveTicket

Ticketing Process

TicketRequest

BE

GIN

EN

D

EstablishSpecialNeeds

TicketReserved

SearchLoyalty

Program

PickLocation

CreditCard

Verification

IssueTicket

ReserveTicket

BAM as an Early Warning System

Bill Gassman, David McCoy, Web Services & Application Integration Conference 2003 17–19 November 2003

Credit Card Verification

CreditCard

Verification

getName

getCreditCardgetNumber

contactCCAgent

Visualizing RTI

Animation

Virtualization and Carrier-Level Service• Recovery-Oriented Computing

• The network of software components share the same memory– An error or attack can corrupt all

memory within the OS and its applications

– Solution –reboot, which initializes all components

• Partition dependent components using virtualization– Failure causes re-booting of

dependent components

http://roc.cs.berkeley.edu/papers/ROC_TR02-1175.pdf

Virtualization Benchmarks

• Tiled Workload– Mail Server – Actions / Minute

– Java Server – New Orders / Sec

– Standby Server – N/A

– Web Server - Accesses / Sec

– Database Server – Commits / Sec

– File Server - MB/second

• Scores are Aggregated

http://www.vmware.com/pdf/vmmark_intro.pdf

Virtualization Benchmark

Workload W I1 I2 I3

Mail server 660 891 917 935

Java server 13174 13285 13249 13310

Standby server - - - -

Web server 851 835 836 833

Database server 897 940 936 951

File server 7.23 6.93 6.84 6.79

Workload I1 I2 I3

Mail server 1.35 1.39 1.42

Java server 1.01 1.01 1.01

Standby server - - -

Web server .98 .98 .98

Database server 1.05 1.04 1.06

File server .96 .95 .94

Geometric Mean 1.08 1.06 1.07

NormalizedRaw

The Future and Beyond

• Expect to see new applications of virtualization

• Closely monitor successes/failures in high transaction and data-intensive environments

• Will Xen Survive?

• When will Viridian see the light of day?