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81d68a96a3
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Steven Rostedt 81d68a96a3 ftrace: trace irq disabled critical timings 
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 <mingo@elte.hu>
--------------------------------------------------------------------
 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 <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:32:46 +02:00
..
acpi
asm-alpha asm-{alpha,h8300,um,v850,xtensa}/param.h: unbreak HZ for userspace 2008-05-14 19:11:14 -07:00
asm-arm Merge branch 'omap-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6 2008-05-17 22:56:29 +01:00
asm-avr32 avr32: types: use <asm-generic/int-*.h> for the avr32 architecture 2008-05-02 16:18:20 -07:00
asm-blackfin Blackfin serial driver: add extra IRQ flag for 8250 serial driver 2008-05-17 18:21:57 +08:00
asm-cris cris: types: use <asm-generic/int-*.h> for the cris architecture 2008-05-02 16:18:20 -07:00
asm-frv read_barrier_depends arch fixlets 2008-05-14 10:05:18 -07:00
asm-generic types: add C99-style constructors to <asm-generic/int-*.h> 2008-05-02 16:18:42 -07:00
asm-h8300 asm-{alpha,h8300,um,v850,xtensa}/param.h: unbreak HZ for userspace 2008-05-14 19:11:14 -07:00
asm-ia64 KVM: ia64: Set KVM_IOAPIC_NUM_PINS to 48 2008-05-18 14:34:16 +03:00
asm-m32r m32r: types: use <asm-generic/int-*.h> for the m32r architecture 2008-05-02 16:18:21 -07:00
asm-m68k m68k: Prefix ISA type with ISA_TYPE_ 2008-05-18 13:28:50 -07:00
asm-m68knommu m68knommu: rework definition of HZ 2008-05-01 08:08:36 -07:00
asm-mips [MIPS] Get rid of __ilog2 2008-05-12 16:46:55 +01:00
asm-mn10300 MN10300: Make cpu_relax() invoke barrier() 2008-05-08 10:49:39 -07:00
asm-parisc parisc: use conditional macro for 64-bit wide ops 2008-05-15 11:03:43 -04:00
asm-powerpc [POWERPC] Fix uninitialized variable bug in copy_{to|from}_user 2008-05-15 20:49:52 +10:00
asm-ppc [POWERPC] ppc: More compile fixes 2008-05-12 22:57:51 +10:00
asm-s390 [S390] s390dbf: Use const char * for dbf name. 2008-05-15 16:52:39 +02:00
asm-sh sh: use the common ascii hex helpers 2008-05-16 15:09:08 +09:00
asm-sparc sparc: remove CVS keywords 2008-05-20 00:33:44 -07:00
asm-sparc64 sparc64: Add global register dumping facility. 2008-05-20 00:33:45 -07:00
asm-um asm-{alpha,h8300,um,v850,xtensa}/param.h: unbreak HZ for userspace 2008-05-14 19:11:14 -07:00
asm-v850 asm-{alpha,h8300,um,v850,xtensa}/param.h: unbreak HZ for userspace 2008-05-14 19:11:14 -07:00
asm-x86 ftrace: trace irq disabled critical timings 2008-05-23 20:32:46 +02:00
asm-xtensa asm-{alpha,h8300,um,v850,xtensa}/param.h: unbreak HZ for userspace 2008-05-14 19:11:14 -07:00
crypto [CRYPTO] api: Fix scatterwalk_sg_chain 2008-05-01 18:22:28 +08:00
keys
linux ftrace: trace irq disabled critical timings 2008-05-23 20:32:46 +02:00
math-emu
media Fix a deadlock in the bttv driver 2008-05-20 10:12:26 -07:00
mtd
net Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/linville/wireless-2.6 2008-05-19 16:29:40 -07:00
pcmcia
rdma IB: expand ib_umem_get() prototype 2008-04-29 08:06:12 -07:00
rxrpc
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2008-05-02 13:52:35 -07:00
sound [ALSA] ASoC: build fix for snd_soc_info_bool_ext 2008-05-13 14:47:44 +02:00
video fbdev: platforming hecubafb and n411 2008-04-28 08:58:41 -07:00
xen xen: add balloon driver 2008-04-24 23:57:33 +02:00
Kbuild