No SATA performance regression observed. ** Tags removed: verification-needed-bionic ** Tags added: verification-done-bionic
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1794165 Title: hisi_sas: Reduce unnecessary spin lock contention Status in linux package in Ubuntu: Fix Committed Status in linux source package in Bionic: Fix Committed Status in linux source package in Cosmic: Fix Committed Bug description: [Impact] The current design of hisi_sas_task_prep() has two critical sections protected by different spin locks. This can lead to unnecessary thrashing. By merging the critical sections under one spin lock, we can avoid this. [Test Case] Use fio to measure performance difference, and verify that there is no performance decrease. Sample config attached. Test on D05 and D06 systems, since both are impacted. [Fix] commit 6cca51ee0aa2540d648ff8698c3889330d897f27 Author: Xiang Chen <chenxian...@hisilicon.com> Date: Wed Jul 18 22:14:31 2018 +0800 scsi: hisi_sas: Tidy hisi_sas_task_prep() [Regression Risk] It's possible that decreasing the lock granularity like this will lead to unforeseen latency issues. However, the additional work done under the new spin lock is just a single list_add_tail() call, which appears to run in constant time. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1794165/+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
