Exactly, Joseph. I'm attaching the exact patch I used for building the test kernel.
** Patch added: "0001-Revert-blk-mq-remove-the-request_list-usage.patch" https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1828248/+attachment/5263471/+files/0001-Revert-blk-mq-remove-the-request_list-usage.patch -- 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/1828248 Title: [linux-azure] Storage performance drop on RAID Status in linux-azure package in Ubuntu: New Status in linux-azure source package in Xenial: Fix Committed Bug description: In Azure, FIO 4k tests are showing performance drops on latest proposed 4.15.0 linux-azure kernels - from 52K IOPS to ~38K IOPS (max value reached on both sequential and random read tests). The setup used is 12 disks in RAID0. The affected kernels are: Ubuntu 14.04 + 4.15.0-1043 Ubuntu 16.04 + 4.15.0-1044 Previous kernel versions had reached max IOPS, ~52K IOPS on both read tests (e.g. 16.04 + 4.15.0-1043 kernel). Right now, it seems like the issue is in the diff from 1043 kernel on trusty vs 1044 kernel on xenial. The 52K IOPS is expected at qdepth=256. The repro cmd (as ran by the automation) is this: fio --size=1023G --direct=1 --ioengine=libaio --filename=/dev/md0 --overwrite=1 --readwrite=randread --bs=4K --runtime=300 --iodepth=32 --numjob=8 --output-format=json --output=/root/FIOLog/jsonLog/fio-result-randread-4K-256td.json --name='repro' To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1828248/+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
