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https://github.com/edk2-porting/linux-next.git
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81d68a96a3
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>
82 lines
1.8 KiB
ArmAsm
82 lines
1.8 KiB
ArmAsm
/*
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* Save registers before calling assembly functions. This avoids
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* disturbance of register allocation in some inline assembly constructs.
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* Copyright 2001,2002 by Andi Kleen, SuSE Labs.
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* Added trace_hardirqs callers - Copyright 2007 Steven Rostedt, Red Hat, Inc.
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* Subject to the GNU public license, v.2. No warranty of any kind.
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*/
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#include <linux/linkage.h>
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#include <asm/dwarf2.h>
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#include <asm/calling.h>
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#include <asm/rwlock.h>
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/* rdi: arg1 ... normal C conventions. rax is saved/restored. */
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.macro thunk name,func
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.globl \name
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\name:
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CFI_STARTPROC
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SAVE_ARGS
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call \func
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jmp restore
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CFI_ENDPROC
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.endm
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/* rdi: arg1 ... normal C conventions. rax is passed from C. */
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.macro thunk_retrax name,func
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.globl \name
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\name:
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CFI_STARTPROC
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SAVE_ARGS
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call \func
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jmp restore_norax
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CFI_ENDPROC
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.endm
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.section .sched.text, "ax"
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#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM
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thunk rwsem_down_read_failed_thunk,rwsem_down_read_failed
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thunk rwsem_down_write_failed_thunk,rwsem_down_write_failed
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thunk rwsem_wake_thunk,rwsem_wake
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thunk rwsem_downgrade_thunk,rwsem_downgrade_wake
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#endif
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#ifdef CONFIG_TRACE_IRQFLAGS
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/* put return address in rdi (arg1) */
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.macro thunk_ra name,func
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.globl \name
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\name:
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CFI_STARTPROC
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SAVE_ARGS
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/* SAVE_ARGS pushs 9 elements */
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/* the next element would be the rip */
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movq 9*8(%rsp), %rdi
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call \func
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jmp restore
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CFI_ENDPROC
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.endm
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thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller
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thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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thunk lockdep_sys_exit_thunk,lockdep_sys_exit
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#endif
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/* SAVE_ARGS below is used only for the .cfi directives it contains. */
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CFI_STARTPROC
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SAVE_ARGS
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restore:
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RESTORE_ARGS
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ret
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CFI_ENDPROC
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CFI_STARTPROC
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SAVE_ARGS
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restore_norax:
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RESTORE_ARGS 1
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ret
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CFI_ENDPROC
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