> -----Original Message----- > From: linux-kernel-owner@xxxxxxxxxxxxxxx <linux-kernel- > owner@xxxxxxxxxxxxxxx> On Behalf Of Kees Cook > Sent: Friday, September 21, 2018 2:13 PM > Subject: Re: [PATCH 0/3] mm: Randomize free memory ... > I'd be curious to hear more about the mentioned cache performance > improvements. I love it when a security feature actually _improves_ > performance. :) It's been a problem in the HPC space: http://www.nersc.gov/research-and-development/knl-cache-mode-performance-coe/ A kernel module called zonesort is available to try to help: https://software.intel.com/en-us/articles/xeon-phi-software and this abandoned patch series proposed that for the kernel: https://lkml.org/lkml/2017/8/23/195 Dan's patch series doesn't attempt to ensure buffers won't conflict, but also reduces the chance that the buffers will. This will make performance more consistent, albeit slower than "optimal" (which is near impossible to attain in a general-purpose kernel). That's better than forcing users to deploy remedies like: "To eliminate this gradual degradation, we have added a Stream measurement to the Node Health Check that follows each job; nodes are rebooted whenever their measured memory bandwidth falls below 300 GB/s." --- Robert Elliott, HPE Persistent Memory
