Enable ftrace function profiler

Bug #570389 reported by Chase Douglas on 2010-04-26
16
This bug affects 2 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Wishlist
Chase Douglas
Lucid
Wishlist
Chase Douglas
Maverick
Wishlist
Chase Douglas

Bug Description

SRU Justification:

Impact: Without function profiling we may have a more difficult time resolving performance issues.

How Addressed: The ftrace function profiler is turned on in the common kernel configs.

Reproduction: No ftrace function profiling is possible on current Ubuntu 10.04 LTS kernel. If it were, the file /sys/kernel/debug/tracing/function_profile_enabled would exist.

Regression Potential: Enabling this functionality is an added bonus to Ubuntu that should not cause any regressions. Further, regressions should be localized to the ftrace subsystem, which will not affect the vast majority of users.

=====

The ftrace framework has profiling capabilities that will be useful in
tracking desktop responsiveness. As an example, profiling can tell us
how many times an ISR is run, and how long the average run time is.

This option will not have any performance impact. When turned on at
runtime, a small performance impact may be seen, and a few hundred KB
per cpu of buffer pages will be allocated and used.

Extremely brief overview:

echo 1 > /sys/kernel/debug/tracing/function_profile_enabled
... run tests ...
echo 0 > /sys/kernel/debug/tracing/function_profile_enabled
cat /sys/kernel/debug/tracing/trace_stat/function0 (suffix: cpu #)

Chase Douglas (chasedouglas) wrote :
Changed in linux (Ubuntu):
assignee: nobody → Chase Douglas (chasedouglas)
status: New → In Progress
importance: Undecided → Wishlist
milestone: none → lucid-updates
Andy Whitcroft (apw) on 2010-05-04
Changed in linux (Ubuntu):
status: In Progress → Fix Committed
Changed in linux (Ubuntu Lucid):
status: New → Fix Committed
importance: Undecided → Wishlist
Changed in linux (Ubuntu):
status: Fix Committed → In Progress
Changed in linux (Ubuntu Lucid):
assignee: nobody → Chase Douglas (chasedouglas)
milestone: none → lucid-updates
Changed in linux (Ubuntu):
milestone: lucid-updates → none
Martin Pitt (pitti) on 2010-06-11
Changed in linux (Ubuntu Maverick):
milestone: none → maverick-alpha-2

Accepted linux into lucid-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

tags: added: verification-needed
Chase Douglas (chasedouglas) wrote :

I've verified that the function profiler works correctly in the new package.

tags: added: verification-done
removed: verification-needed
Changed in linux (Ubuntu Maverick):
status: In Progress → Fix Released
Chase Douglas (chasedouglas) wrote :

The function profiler is already turned on in Maverick.

Launchpad Janitor (janitor) wrote :
Download full text (25.2 KiB)

This bug was fixed in the package linux - 2.6.32-23.37

---------------
linux (2.6.32-23.37) lucid-proposed; urgency=low

  [ Alex Deucher ]

  * SAUCE: drm/radeon/kms/atom: fix dual-link DVI on DCE3.2/4.0
    - LP: #564559

  [ Andy Whitcroft ]

  * [Config] ports -- build in dm-mod to enable LVM boot
    - LP: #560717
  * tools -- fix perf version extraction for multi-part flavours
    - LP: #555130
  * SAUCE: ACPI: EC: Allow multibyte access to EC (v3)
    - LP: #526354
  * [Config] enforce -- ensure dm_mod is built-in for LVM
    - LP: #560717
  * update to ubuntu-debian:7e708d33054c373faf41da23b73e8b48c342d958
    - LP: #570500, #576274

  [ Chase Douglas ]

  * Revert "(pre-stable): input: ALPS - Add signature for HP Pavilion dm3
    laptops"
    - LP: #550625
  * Enable ftrace function profiler
    - LP: #570389
  * enforce CONFIG_TMPFS_POSIX_ACL=y
    - LP: #575940

  [ Leann Ogasawara ]

  * Revert "staging/comdi -- disable"
    - LP: #563436
  * [Config] Enable multicast routing for sparc
    - LP: #416266
  * [Config] Add ahci.ko to virtual sub-flavour
    - LP: #570542

  [ Stefan Bader ]

  * Revert "SAUCE: drm/i915: Disable FBC on 915GM and 945GM"
    - LP: #588832

  [ Tim Gardner ]

  * ubuntu: rtl8192se -- update to version 0015.0127.2010
    - LP: #567016
  * [Config] Add atl1c to nic-modules udeb
    - LP: #557130

  [ Upstream Kernel Changes ]

  * Revert "(pre-stable) iwlwifi: fix nfreed--"
    - LP: #575853
  * Revert "backlight: mbp_nvidia_bl - add five more MacBook variants"
    - LP: #575853
  * Revert "(pre-stable) pata_via: Add VIA VX900 support"
    - LP: #575853
  * Revert "(pre-stable) x86-32, resume: do a global tlb flush in S4
    resume"
    - LP: #575853
  * Revert "x86: disable IOMMUs on kernel crash"
    - LP: #575853
  * Revert "sunrpc: fix peername failed on closed listener"
    - LP: #575853
  * Revert "sunrpc: move the close processing after do recvfrom method"
    - LP: #575853
  * Revert "(pre-stable) drm/edid: allow certain bogus edids to hit a fixup
    path rather than fail"
    - LP: #575853
  * Revert "drm/radeon/kms: don't print error on -ERESTARTSYS."
    - LP: #575853
  * Revert "ath9k: fix lockdep warning when unloading module" on stable
    kernels
    - LP: #588832
  * Staging: comedi: removed "depricated" from COMEDI_CB_BLOCK
    - LP: #483343
  * fat: fix buffer overflow in vfat_create_shortname()
    - LP: #575853
  * xfs: simplify inode teardown
    - LP: #575853
  * xfs: fix mmap_sem/iolock inversion in xfs_free_eofblocks
    - LP: #575853
  * xfs: I/O completion handlers must use NOFS allocations
    - LP: #575853
  * xfs: Wrapped journal record corruption on read at recovery
    - LP: #575853
  * xfs: Fix error return for fallocate() on XFS
    - LP: #575853
  * xfs: check for not fully initialized inodes in xfs_ireclaim
    - LP: #575853
  * xfs: fix timestamp handling in xfs_setattr
    - LP: #575853
  * xfs: Don't flush stale inodes
    - LP: #575853
  * xfs: Ensure we force all busy extents in range to disk
    - LP: #575853
  * xfs: reclaim inodes under a write lock
    - LP: #575853
  * xfs: Avoid inodes in reclaim when flushing from inode cache
    - LP: #575853
  * xfs: recla...

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