I tested the change on Azure using Standard L8s_v2 (8 vcpus, 64 GiB memory) VMs using the 5.4 linux-azure kernel on bionic and the 5.8 kernel on groovy.
During my tests the VMs continued to successfully hibernate with the patch and the time needed to save the VM state went down from 25 seconds to around 3 seconds. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-azure in Ubuntu. https://bugs.launchpad.net/bugs/1904458 Title: [linux-azure] Batch hibernate and resume IO requests Status in linux-azure package in Ubuntu: New Status in linux-azure source package in Focal: In Progress Status in linux-azure source package in Groovy: In Progress Bug description: [Impact] Microsoft would like to request the following upstream commit in all releases supported on Azure. This commit improves a signification delay in hibernation/resume: 55c4478a8f0e("PM: hibernate: Batch hibernate and resume IO requests") Details of this commit: Hibernate and resume process submits individual IO requests for each page of the data, so use blk_plug to improve the batching of these requests. Testing this change with hibernate and resumes consistently shows merging of the IO requests and more than an order of magnitude improvement in hibernate and resume speed is observed. One hibernate and resume cycle for 16GB RAM out of 32GB in use takes around 21 minutes before the change, and 1 minutes after the change on a system with limited storage IOPS. [Test Case] Follow the steps described here: https://bugs.launchpad.net/ubuntu/+source/linux- azure/+bug/1880032/comments/14 And compare the time need to save the instance state. [Where problems could occur] Considering the size of the patch and the code it touches, the most likely issues are related to hibernation itself. Considering the hibernation isn't officially support, any hibernation issues should even considered regressions. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1904458/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
