The Measured Performance of
Personal Computer Operating Systems
J. Bradley Chen, Yasuhiro Endo, Kee Chan, David Mazières
Antonio Dias, Margo Seltzer, and Michael D. Smith
Division of Applied Sciences
Harvard University
Abstract
This paper presents a comparative study of the performance of
three operating systems that run on the personal computer architecture
derived from the IBM-PC. The operating systems, Windows
for Workgroups, Windows NT, and NetBSD (a freely
available variant of the UNIX operating system), cover a broad
range of system functionality and user requirements, from a single
address space model to full protection with preemptive multi-tasking.
Our measurements were enabled by hardware counters in
Intel’s Pentium processor that permit measurement of a broad
range of processor events including instruction counts and on-chip
cache miss counts. We used both microbenchmarks, which expose
specific differences between the systems, and application workloads,
which provide an indication of expected end-to-end performance.
Our microbenchmark results show that accessing system
functionality is often more expensive in Windows for Workgroups
than in the other two systems due to frequent changes in machine
mode and the use of system call hooks. When running native
applications, Windows NT is more efficient than Windows, but it
incurs overhead similar to that of a microkernel since its application
interface (the Win32 API) is implemented as a user-level
server. Overall, system functionality can be accessed most effi-
ciently in NetBSD; we attribute this to its monolithic structure, and
to the absence of the complications created by hardware backwards
compatibility requirements in the other systems. Measurements
of application performance show that although the impact of
these differences is significant in terms of instruction counts and
other hardware events (often a factor of 2 to 7 difference between
the systems), overall...