This research summary describes research conducted under the Harvard University Computer Science Department's


J. Bradley Chen, Yasuhiro Endo, Kee Chan, David Mazieres, Antonio Dias, Margo Seltzer, Michael D. Smith August 1995


Resources available on-line

Excerpts from the paper

The Syscall Benchmark

This benchmark measures the time required to invoke a system call. Windows for Workgroups implements some of the functionality in 32-bit code and some in 16-bit. We tested both. Our results show that accessing 32-bit Windows system functionality has the lowest overhead, while accessing 16-bit Windows system functionality incurs overhead similar to that of Windows NT. Overall, NetBSD allows more efficient access to the system functionality than the other two systems. Read the paper for detail.

Memory Access Time

We used the memory read microbenchmark from lmbench (written by Larry McVoy) to measure average memory access time for repeated references to arrays of various sizes, using a stride of 128bytes. The results are affected by addressing schemes and page mapping policies.


These figures illustrate activity during a run of the Ghostscript previewer on a 13 page, 372K byte conference paper. Windows NT gains significant performance benefit from its graphics implementation, which makes efficient use of special features in the graphics hardware. NetBSD suffers from the additional copies and device-independent implementation of our X11 server.

Yasuhiro Endo /