Revision as of 15:04, 16 November 2010

Background Concepts

In this section we will discuss the fundamentals of timekeeping in real and virtual machines.

This section will provide a brief overview of timekeeping in stand-alone or host PCs/servers.

todo: add a diagram of a simplified timer showing oscillator, counter, counter input, and interrupt
todo: explain the parts of the diagram

This section will explain why timing is different for guest operating systems.

Discuss what causes the problem in virtual environments. Consider para-virtual and full-virtual architectures.

Discuss the impact of error on a few real-world applications.

Discuss common strategies in VM software and in operating systems to compensate for drift. Discuss what happens when the clock is slow and fast.

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 =Background Concepts=
+In this section we will discuss the fundamentals of timekeeping in real and virtual machines.
+==Host Timekeeping==
+This section will provide a brief overview of timekeeping in stand-alone or host PCs/servers.
+#todo: add a diagram of a simplified timer showing oscillator, counter, counter input, and interrupt
+#todo: explain the parts of the diagram
+===Counting Strategies===
+# tick counting
+# tickless counting
+===Timers===
+# PIT
+# CMOS RTC
+# Local APIC
+# ACPI
+# TSC
+# HPET
+==Guest Timekeeping==
+This section will explain why timing is different for guest operating systems.
+===Sources of Drift===
+Discuss what causes the problem in virtual environments. Consider para-virtual and full-virtual architectures.
+===Impact of Drift===
+Discuss the impact of error on a few real-world applications.
+===Compensation Strategies===
+Discuss common strategies in VM software and in operating systems to compensate for drift. Discuss what happens when the clock is slow and fast.
 =Research problem=
 =Contribution=
 =Critique=
 =References=