[SRU] arm64 performance regression in wily 4.2 kernel on m400 due to dropped patch

Bug #1508471 reported by Craig Magina
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Fix Released
Undecided
Craig Magina
Wily
Fix Released
Undecided
Unassigned

Bug Description

[Impact]
Performance Regression.

The copy_{to,from}_user implementations in the Ubuntu kernel are suboptimal. Optimized implementations have been accepted upstream and have shown a significant improvement in network performance. Previous Ubuntu releases included non-upstream versions of these patches, but they were dropped during the wily cycle.

[Test Case]
Generate traffic from one node to another using iperf.

[Regression Risk]
These functions are obviously used heavily throughout the kernel, so a defect here could have significant impact. However, it has been accepted by upstream after some cycles of review, and we have shipped earlier versions of it in every arm64 release prior to wily. The backported patches have also been tested on real arm64 hardware.

Changed in linux (Ubuntu):
status: New → In Progress
assignee: nobody → Craig Magina (craig.magina)
summary: - arm64 performance regression in wily 4.2 kernel on m400 due to dropped
- patch
+ [SRU] arm64 performance regression in wily 4.2 kernel on m400 due to
+ dropped patch
description: updated
dann frazier (dannf)
description: updated
description: updated
Brad Figg (brad-figg)
Changed in linux (Ubuntu):
status: In Progress → Fix Committed
Luis Henriques (henrix)
Changed in linux (Ubuntu Wily):
status: New → Fix Committed
Revision history for this message
Launchpad Janitor (janitor) wrote :
Download full text (32.9 KiB)

This bug was fixed in the package linux - 4.2.0-19.23

---------------
linux (4.2.0-19.23) wily; urgency=low

  [ Luis Henriques ]

  * Release Tracking Bug
    - LP: #1515157

  [ Andy Whitcroft ]

  * [Config] re-enable OSS support and blacklist
    - LP: #1434842

  [ dann frazier ]

  * Revert "[Config] CONFIG_ARM64_ERRATUM_843419=n"
    - LP: #1502946

  [ Paolo Pisati ]

  * [SRU] [Config] armhf: LEDS_TRIGGER_HEARTBEAT=y
    - LP: #1510165

  [ Tim Gardner ]

  * [Config] Add iscsi_ibft and iscsi_boot_sysfs to generic inclusion list
    - LP: #1511006
  * [Config] CONFIG_AUFS_EXPORT=y
    - LP: #1121699

  [ Upstream Kernel Changes ]

  * Revert "KVM: x86: apply guest MTRR virtualization on host reserved
    pages"
    - LP: #1509886
  * Revert "KVM: SVM: use NPT page attributes"
    - LP: #1509886
  * Revert "KVM: SVM: Sync g_pat with guest-written PAT value"
    - LP: #1509886
  * Revert "cgroup: simplify threadgroup locking"
    - LP: #1509886
  * Revert "sched, cgroup: replace signal_struct->group_rwsem with a global
    percpu_rwsem"
    - LP: #1509886
  * Revert "ARM64: unwind: Fix PC calculation"
    - LP: #1514889
  * Revert "serial: 8250_dma: don't bother DMA with small transfers"
    - LP: #1514889
  * Revert "md: allow a partially recovered device to be hot-added to an
    array."
    - LP: #1514889
  * arm64: Change memcpy in kernel to use the copy template file
    - LP: #1508471
  * arm64: copy_to-from-in_user optimization using copy template
    - LP: #1508471
  * Input: elan_i2c - enable ELAN0600 acpi panels
    - LP: #1439111
  * e1000e: Fix tight loop implementation of systime read algorithm
  * arm: KVM: Fix incorrect device to IPA mapping
    - LP: #1509886
  * KVM: vmx: fix VPID is 0000H in non-root operation
    - LP: #1509886
  * kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd
    - LP: #1509886
  * kvm: fix zero length mmio searching
    - LP: #1509886
  * kvm: factor out core eventfd assign/deassign logic
    - LP: #1509886
  * kvm: fix double free for fast mmio eventfd
    - LP: #1509886
  * arm: KVM: Disable virtual timer even if the guest is not using it
    - LP: #1509886
  * kvm: svm: reset mmu on VCPU reset
    - LP: #1509886
  * KVM: x86: trap AMD MSRs for the TSeg base and mask
    - LP: #1509886
  * KVM: PPC: Book3S: Take the kvm->srcu lock in
    kvmppc_h_logical_ci_load/store()
    - LP: #1509886
  * KVM: PPC: Book3S HV: Pass the correct trap argument to
    kvmhv_commence_exit
    - LP: #1509886
  * time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of
    abs64()
    - LP: #1509886
  * target/iscsi: Fix np_ip bracket issue by removing np_ip
    - LP: #1509886
  * scsi: fix scsi_error_handler vs. scsi_host_dev_release race
    - LP: #1509886
  * target: Attach EXTENDED_COPY local I/O descriptors to xcopy_pt_sess
    - LP: #1509886
  * target: Fix PR registration + APTPL RCU conversion regression
    - LP: #1509886
  * iser-target: remove command with state ISTATE_REMOVE
    - LP: #1509886
  * iser-target: Put the reference on commands waiting for unsol data
    - LP: #1509886
  * toshiba_acpi: Fix hotkeys registration on some toshiba models
    - LP: #1509886
  *...

Changed in linux (Ubuntu):
status: Fix Committed → Fix Released
Revision history for this message
Luis Henriques (henrix) wrote :

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-wily' to 'verification-done-wily'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

tags: added: verification-needed-wily
tags: added: verification-done-wily
removed: verification-needed-wily
Revision history for this message
Launchpad Janitor (janitor) wrote :
Download full text (32.9 KiB)

This bug was fixed in the package linux - 4.2.0-19.23

---------------
linux (4.2.0-19.23) wily; urgency=low

  [ Luis Henriques ]

  * Release Tracking Bug
    - LP: #1515157

  [ Andy Whitcroft ]

  * [Config] re-enable OSS support and blacklist
    - LP: #1434842

  [ dann frazier ]

  * Revert "[Config] CONFIG_ARM64_ERRATUM_843419=n"
    - LP: #1502946

  [ Paolo Pisati ]

  * [SRU] [Config] armhf: LEDS_TRIGGER_HEARTBEAT=y
    - LP: #1510165

  [ Tim Gardner ]

  * [Config] Add iscsi_ibft and iscsi_boot_sysfs to generic inclusion list
    - LP: #1511006
  * [Config] CONFIG_AUFS_EXPORT=y
    - LP: #1121699

  [ Upstream Kernel Changes ]

  * Revert "KVM: x86: apply guest MTRR virtualization on host reserved
    pages"
    - LP: #1509886
  * Revert "KVM: SVM: use NPT page attributes"
    - LP: #1509886
  * Revert "KVM: SVM: Sync g_pat with guest-written PAT value"
    - LP: #1509886
  * Revert "cgroup: simplify threadgroup locking"
    - LP: #1509886
  * Revert "sched, cgroup: replace signal_struct->group_rwsem with a global
    percpu_rwsem"
    - LP: #1509886
  * Revert "ARM64: unwind: Fix PC calculation"
    - LP: #1514889
  * Revert "serial: 8250_dma: don't bother DMA with small transfers"
    - LP: #1514889
  * Revert "md: allow a partially recovered device to be hot-added to an
    array."
    - LP: #1514889
  * arm64: Change memcpy in kernel to use the copy template file
    - LP: #1508471
  * arm64: copy_to-from-in_user optimization using copy template
    - LP: #1508471
  * Input: elan_i2c - enable ELAN0600 acpi panels
    - LP: #1439111
  * e1000e: Fix tight loop implementation of systime read algorithm
  * arm: KVM: Fix incorrect device to IPA mapping
    - LP: #1509886
  * KVM: vmx: fix VPID is 0000H in non-root operation
    - LP: #1509886
  * kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd
    - LP: #1509886
  * kvm: fix zero length mmio searching
    - LP: #1509886
  * kvm: factor out core eventfd assign/deassign logic
    - LP: #1509886
  * kvm: fix double free for fast mmio eventfd
    - LP: #1509886
  * arm: KVM: Disable virtual timer even if the guest is not using it
    - LP: #1509886
  * kvm: svm: reset mmu on VCPU reset
    - LP: #1509886
  * KVM: x86: trap AMD MSRs for the TSeg base and mask
    - LP: #1509886
  * KVM: PPC: Book3S: Take the kvm->srcu lock in
    kvmppc_h_logical_ci_load/store()
    - LP: #1509886
  * KVM: PPC: Book3S HV: Pass the correct trap argument to
    kvmhv_commence_exit
    - LP: #1509886
  * time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of
    abs64()
    - LP: #1509886
  * target/iscsi: Fix np_ip bracket issue by removing np_ip
    - LP: #1509886
  * scsi: fix scsi_error_handler vs. scsi_host_dev_release race
    - LP: #1509886
  * target: Attach EXTENDED_COPY local I/O descriptors to xcopy_pt_sess
    - LP: #1509886
  * target: Fix PR registration + APTPL RCU conversion regression
    - LP: #1509886
  * iser-target: remove command with state ISTATE_REMOVE
    - LP: #1509886
  * iser-target: Put the reference on commands waiting for unsol data
    - LP: #1509886
  * toshiba_acpi: Fix hotkeys registration on some toshiba models
    - LP: #1509886
  *...

Changed in linux (Ubuntu Wily):
status: Fix Committed → Fix Released
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