1. Feature Optimization for zero-filled pages written by VMs https://jira.sw.ru/browse/PSBM-64658
2. Description Any page before being written to the physical swap is checked if it is filled by zeroes and mapped to a zero page in this case instead of actual swap out. The feature is implemented on the tswap level, so the page is checked for zeroes before putting to tswap. Usecase when the feature is expected to provide most performance boost: many Windows-based VMs started simultaneously on a Hardware Node with overcommit => on any restart of an overcommitted HN which runs Windows-based VMs. Windows-based VMs are chosen here because Windows is known to rewrite its RAM with zeroes on boot and lazily while it is running. 3. Products Virtuozzo 7 Packages versions (or later): vzkernel-3.10.0-514.26.1.vz7.35.8 4. Testing Start N Windows-based VMs in parallel, wait until they are started - time T. Time T should be significantly less when running a kernel with the feature. N should be chosen so the Hardware Node is overcommitted by memory. Another parameter to monitor: swapout should be much less when running on kernel with the feature enabled. 5. Known issues tswap is a front swap and thus it works only in case physical swap is configured on the Hardware Node. 6. Feature owner Kirill Tkhai <ktk...@virtuozzo.com> -- Best regards, Konstantin Khorenko, Virtuozzo Linux Kernel Team _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel