Public bug reported: [Impact] A ~12% performance gain can be achieved with the iperf benchmark by allowing the ixgbe driver to take advantage of PCIe Relaxed Ordering, as observed on the HiSilicon D05 system.
[Test Case] iperf command TBD [Regression Risk] The patchset is careful to only enable Relaxed Ordering if advertised up through the root port. However, it is possible that enabling RO on hardware that supports it could actually regress performance, or that there is hw out there that advertises RO, but has bugs in the implementation. The patch series includes quirks for HW where RO is advertised but known to have issues[*] - but this list maybe incomplete. This would only impact devices w/ drivers that take advantage of RO - currently cxgb4 and (not yet upstream) ixgbe. Also, there is a possibility of a crash caused by a coding error. One such issue has already been found and fixed upstream [**], and is part of this series. The risk of both of these regressions is reduced by the fact that this code is now in an upstream release (v4.13) and has therefore gotten a lot more testing that has not resulted in regressions reports. [*] commit 077fa19c5dfa06a6ae04fb1661680940ff837612 Author: dingtianhong <[email protected]> Date: Tue Aug 15 11:23:25 2017 +0800 PCI: Disable Relaxed Ordering Attributes for AMD A110 commit 87e09cdec4dae08acdb4aa49beb793c19d73e73e Author: dingtianhong <[email protected]> Date: Tue Aug 15 11:23:24 2017 +0800 PCI: Disable Relaxed Ordering for some Intel processors [**] commit 0e405232871d67bf1b238d56b6b3d500e69ebbf3 Author: dingtianhong <[email protected]> Date: Tue Aug 15 23:24:48 2017 +0800 PCI: fix oops when try to find Root Port for a PCI device ** Affects: linux (Ubuntu) Importance: Medium Status: Fix Released ** Affects: linux (Ubuntu Zesty) Importance: Undecided Assignee: dann frazier (dannf) Status: Confirmed ** Also affects: linux (Ubuntu Zesty) Importance: Undecided Status: New ** Changed in: linux (Ubuntu Zesty) Status: New => Confirmed ** Changed in: linux (Ubuntu Zesty) Assignee: (unassigned) => dann frazier (dannf) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1721365 Title: PCIe: Allow drivers to use Relaxed Ordering on capable root ports To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1721365/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
