Threads Executing on 1 CPU (OS-X)

The following visualizations show thread scheduling of CPU-bound threads on a single CPU of a Mac OS-X system (described below). Observe how threads alternate execution in large blocks of time. This is good--you want this kind of behavior to avoid excessive context-switching. If you don't care about OS-X, view the Linux version of this page.

OS-X, 2 Threads, 1 CPU [ code ]

OS-X, 4 Threads, 1 CPU [ code ]

Test Details

Tests were conducted on the following system:

• Python 2.6
• MacPro 2 x 2.66 Ghz Dual-Core Intel Xeon, 3GB 667 Mhz DDR2 FB-DIMM
• OS-X 10.6.2 (Snow Leopard)
• 3 CPU cores were disabled using the Processor Preference Pane

Take Me To More Visualizations!

• Threads running on 1 CPU

• 2 CPU bound threads running on 1 and 2 CPUs

• 4 CPU bound threads running on 1, 2, and 4 CPUs

• A CPU-bound thread and an I/O bound thread on 1 and 2 CPUs

• 512 I/O bound threads running on 2 CPUs

• 512 I/O bound threads running on 1 CPU