How do I programmatically disable hardware prefetching?

Question

I would like to programmatically disable hardware prefetching.

From Optimizing Application Performance on Intel® Core™ Microarchitecture Using Hardware-Implemented

Answer 1

You can enable or disable the hardware prefetchers using msr-tools http://www.kernel.org/pub/linux/utils/cpu/msr-tools/.

The following enables the hardware prefetcher (by unsetting bit 9):

[root@... msr-tools-1.2]# ./wrmsr -p 0 0x1a0 0x60628e2089 
[root@... msr-tools-1.2]# ./rdmsr 0x1a0 
60628e2089

The following disables the hardware prefetcher (by enabling bit 9):

[root@... msr-tools-1.2]# ./wrmsr -p 0 0x1a0 0x60628e2289 
[root@... msr-tools-1.2]# ./rdmsr 0x1a0 
60628e2289

Programatically, you can do this as root by opening /dev/cpu//msr and using pwrite to write to the msr "file" at the 0x1a0 offset.