23 Oct, 2009

1 commit


13 Mar, 2009

1 commit


26 Jul, 2008

1 commit

  • There haave been several areas in the kernel where an int has been used for
    flags in local_irq_save() and friends instead of a long. This can cause some
    hard to debug problems on some architectures.

    This patch adds a typecheck inside the irqsave and restore functions to flag
    these cases.

    [akpm@linux-foundation.org: coding-style fixes]
    [akpm@linux-foundation.org: build fix]
    Signed-off-by: Steven Rostedt
    Cc: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Steven Rostedt
     

24 May, 2008

2 commits

  • Add preempt off timings. A lot of kernel core code is taken from the RT patch
    latency trace that was written by Ingo Molnar.

    This adds "preemptoff" and "preemptirqsoff" to /debugfs/tracing/available_tracers

    Now instead of just tracing irqs off, preemption off can be selected
    to be recorded.

    When this is selected, it shares the same files as irqs off timings.
    One can either trace preemption off, irqs off, or one or the other off.

    By echoing "preemptoff" into /debugfs/tracing/current_tracer, recording
    of preempt off only is performed. "irqsoff" will only record the time
    irqs are disabled, but "preemptirqsoff" will take the total time irqs
    or preemption are disabled. Runtime switching of these options is now
    supported by simpling echoing in the appropriate trace name into
    /debugfs/tracing/current_tracer.

    Signed-off-by: Steven Rostedt
    Signed-off-by: Ingo Molnar
    Signed-off-by: Thomas Gleixner

    Steven Rostedt
     
  • This patch adds latency tracing for critical timings
    (how long interrupts are disabled for).

    "irqsoff" is added to /debugfs/tracing/available_tracers

    Note:
    tracing_max_latency
    also holds the max latency for irqsoff (in usecs).
    (default to large number so one must start latency tracing)

    tracing_thresh
    threshold (in usecs) to always print out if irqs off
    is detected to be longer than stated here.
    If irq_thresh is non-zero, then max_irq_latency
    is ignored.

    Here's an example of a trace with ftrace_enabled = 0

    =======
    preemption latency trace v1.1.5 on 2.6.24-rc7
    Signed-off-by: Ingo Molnar
    --------------------------------------------------------------------
    latency: 100 us, #3/3, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
    -----------------
    | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0)
    -----------------
    => started at: _spin_lock_irqsave+0x2a/0xb7
    => ended at: _spin_unlock_irqrestore+0x32/0x5f

    _------=> CPU#
    / _-----=> irqs-off
    | / _----=> need-resched
    || / _---=> hardirq/softirq
    ||| / _--=> preempt-depth
    |||| /
    ||||| delay
    cmd pid ||||| time | caller
    \ / ||||| \ | /
    swapper-0 1d.s3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000])
    swapper-0 1d.s3 100us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000])
    swapper-0 1d.s3 100us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f)

    vim:ft=help
    =======

    And this is a trace with ftrace_enabled == 1

    =======
    preemption latency trace v1.1.5 on 2.6.24-rc7
    --------------------------------------------------------------------
    latency: 102 us, #12/12, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
    -----------------
    | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0)
    -----------------
    => started at: _spin_lock_irqsave+0x2a/0xb7
    => ended at: _spin_unlock_irqrestore+0x32/0x5f

    _------=> CPU#
    / _-----=> irqs-off
    | / _----=> need-resched
    || / _---=> hardirq/softirq
    ||| / _--=> preempt-depth
    |||| /
    ||||| delay
    cmd pid ||||| time | caller
    \ / ||||| \ | /
    swapper-0 1dNs3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000])
    swapper-0 1dNs3 46us : e1000_read_phy_reg+0x16/0x225 [e1000] (e1000_update_stats+0x5e2/0x64c [e1000])
    swapper-0 1dNs3 46us : e1000_swfw_sync_acquire+0x10/0x99 [e1000] (e1000_read_phy_reg+0x49/0x225 [e1000])
    swapper-0 1dNs3 46us : e1000_get_hw_eeprom_semaphore+0x12/0xa6 [e1000] (e1000_swfw_sync_acquire+0x36/0x99 [e1000])
    swapper-0 1dNs3 47us : __const_udelay+0x9/0x47 (e1000_read_phy_reg+0x116/0x225 [e1000])
    swapper-0 1dNs3 47us+: __delay+0x9/0x50 (__const_udelay+0x45/0x47)
    swapper-0 1dNs3 97us : preempt_schedule+0xc/0x84 (__delay+0x4e/0x50)
    swapper-0 1dNs3 98us : e1000_swfw_sync_release+0xc/0x55 [e1000] (e1000_read_phy_reg+0x211/0x225 [e1000])
    swapper-0 1dNs3 99us+: e1000_put_hw_eeprom_semaphore+0x9/0x35 [e1000] (e1000_swfw_sync_release+0x50/0x55 [e1000])
    swapper-0 1dNs3 101us : _spin_unlock_irqrestore+0xe/0x5f (e1000_update_stats+0x641/0x64c [e1000])
    swapper-0 1dNs3 102us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000])
    swapper-0 1dNs3 102us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f)

    vim:ft=help
    =======

    Signed-off-by: Steven Rostedt
    Signed-off-by: Ingo Molnar
    Signed-off-by: Thomas Gleixner

    Steven Rostedt
     

20 Apr, 2008

1 commit

  • irqs_disabled() uses flags internally, use _flags to avoid shadowing
    code calling into this macro.

    Introduced between 2.6.25-rc3 and -rc4

    Fixes the sparse warning:
    arch/x86/mm/pageattr.c:383:21: warning: symbol 'flags' shadows an earlier one
    arch/x86/mm/pageattr.c:369:16: originally declared here

    Signed-off-by: Harvey Harrison
    Signed-off-by: Ingo Molnar
    Signed-off-by: Thomas Gleixner

    Harvey Harrison
     

04 Jul, 2006

1 commit

  • Accurate hard-IRQ-flags and softirq-flags state tracing.

    This allows us to attach extra functionality to IRQ flags on/off
    events (such as trace-on/off).

    Signed-off-by: Ingo Molnar
    Signed-off-by: Arjan van de Ven
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar