Comment 5 for bug 1783651

I've built and tested 4.15 and the latest 4.18 with the following configs:

CONFIG_PAGE_POISONING=y
CONFIG_PAGE_POISONING_ZERO=y
CONFIG_PAGE_POISONING_NO_SANITY=y

Attached is a libreoffice spreadsheet with the test results comparing kernels without the config, with the config and with the config with page_poison=1 for the 4.18 and 4.15 kernels. I ran nearly 200 stress-ng stress tests and gathered the throughput (based on bogo ops per second on the usr+sys time consumed) for each stress test. Each of the stress tests were run for 60 seconds on an idle 8 thread Xeon i7-3770.

The bogo-ops data was then normalized against the kernel that didn't have the config changes. The data to look at is the geometric means of all the normalized test results:

4.18 kernel, geometric mean of normalized bogo/ops throughput:

No page poisoning: 1.000
Config page poisoning: 1.003
Config page poionsing + page_poison=1: 0.991

4.15 kernel, geometric mean of normalized bogo/ops throughput:

No page poisoning: 1.000
Config page poisoning: 1.025
Config page poionsing + page_poison=1: 0.977

where > 1.000 shows more throughput and < 1.000 shows degraded throughput

So it appears that enabling page poisoning configs does not degrade performance and setting page_poison=1 degrades performance by a very small amount.