forked from Minki/linux
15e6cb3673
Impact: add new tracing plugin which can trace full (entry+exit) function calls This tracer uses the low level function return ftrace plugin to measure the execution time of the kernel functions. The first field is the caller of the function, the second is the measured function, and the last one is the execution time in nanoseconds. - v3: - HAVE_FUNCTION_RET_TRACER have been added. Each arch that support ftrace return should enable it. - ftrace_return_stub becomes ftrace_stub. - CONFIG_FUNCTION_RET_TRACER depends now on CONFIG_FUNCTION_TRACER - Return traces printing can be used for other tracers on trace.c - Adapt to the new tracing API (no more ctrl_update callback) - Correct the check of "disabled" during insertion. - Minor changes... Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
220 lines
6.3 KiB
Plaintext
220 lines
6.3 KiB
Plaintext
#
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# Architectures that offer an FUNCTION_TRACER implementation should
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# select HAVE_FUNCTION_TRACER:
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#
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config NOP_TRACER
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bool
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config HAVE_FUNCTION_TRACER
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bool
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config HAVE_FUNCTION_RET_TRACER
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bool
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config HAVE_FUNCTION_TRACE_MCOUNT_TEST
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bool
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help
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This gets selected when the arch tests the function_trace_stop
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variable at the mcount call site. Otherwise, this variable
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is tested by the called function.
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config HAVE_DYNAMIC_FTRACE
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bool
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config HAVE_FTRACE_MCOUNT_RECORD
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bool
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config TRACER_MAX_TRACE
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bool
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config RING_BUFFER
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bool
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config TRACING
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bool
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select DEBUG_FS
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select RING_BUFFER
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select STACKTRACE if STACKTRACE_SUPPORT
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select TRACEPOINTS
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select NOP_TRACER
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menu "Tracers"
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config FUNCTION_TRACER
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bool "Kernel Function Tracer"
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depends on HAVE_FUNCTION_TRACER
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depends on DEBUG_KERNEL
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select FRAME_POINTER
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select TRACING
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select CONTEXT_SWITCH_TRACER
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help
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Enable the kernel to trace every kernel function. This is done
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by using a compiler feature to insert a small, 5-byte No-Operation
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instruction to the beginning of every kernel function, which NOP
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sequence is then dynamically patched into a tracer call when
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tracing is enabled by the administrator. If it's runtime disabled
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(the bootup default), then the overhead of the instructions is very
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small and not measurable even in micro-benchmarks.
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config FUNCTION_RET_TRACER
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bool "Kernel Function return Tracer"
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depends on !DYNAMIC_FTRACE
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depends on HAVE_FUNCTION_RET_TRACER
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depends on FUNCTION_TRACER
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help
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Enable the kernel to trace a function at its return.
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It's first purpose is to trace the duration of functions.
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This is done by setting the current return address on the thread
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info structure of the current task.
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config IRQSOFF_TRACER
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bool "Interrupts-off Latency Tracer"
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default n
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depends on TRACE_IRQFLAGS_SUPPORT
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depends on GENERIC_TIME
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depends on DEBUG_KERNEL
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select TRACE_IRQFLAGS
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select TRACING
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select TRACER_MAX_TRACE
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help
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This option measures the time spent in irqs-off critical
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sections, with microsecond accuracy.
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The default measurement method is a maximum search, which is
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disabled by default and can be runtime (re-)started
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via:
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echo 0 > /debugfs/tracing/tracing_max_latency
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(Note that kernel size and overhead increases with this option
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enabled. This option and the preempt-off timing option can be
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used together or separately.)
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config PREEMPT_TRACER
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bool "Preemption-off Latency Tracer"
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default n
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depends on GENERIC_TIME
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depends on PREEMPT
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depends on DEBUG_KERNEL
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select TRACING
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select TRACER_MAX_TRACE
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help
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This option measures the time spent in preemption off critical
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sections, with microsecond accuracy.
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The default measurement method is a maximum search, which is
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disabled by default and can be runtime (re-)started
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via:
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echo 0 > /debugfs/tracing/tracing_max_latency
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(Note that kernel size and overhead increases with this option
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enabled. This option and the irqs-off timing option can be
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used together or separately.)
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config SYSPROF_TRACER
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bool "Sysprof Tracer"
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depends on X86
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select TRACING
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help
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This tracer provides the trace needed by the 'Sysprof' userspace
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tool.
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config SCHED_TRACER
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bool "Scheduling Latency Tracer"
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depends on DEBUG_KERNEL
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select TRACING
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select CONTEXT_SWITCH_TRACER
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select TRACER_MAX_TRACE
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help
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This tracer tracks the latency of the highest priority task
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to be scheduled in, starting from the point it has woken up.
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config CONTEXT_SWITCH_TRACER
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bool "Trace process context switches"
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depends on DEBUG_KERNEL
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select TRACING
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select MARKERS
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help
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This tracer gets called from the context switch and records
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all switching of tasks.
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config BOOT_TRACER
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bool "Trace boot initcalls"
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depends on DEBUG_KERNEL
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select TRACING
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select CONTEXT_SWITCH_TRACER
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help
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This tracer helps developers to optimize boot times: it records
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the timings of the initcalls and traces key events and the identity
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of tasks that can cause boot delays, such as context-switches.
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Its aim is to be parsed by the /scripts/bootgraph.pl tool to
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produce pretty graphics about boot inefficiencies, giving a visual
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representation of the delays during initcalls - but the raw
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/debug/tracing/trace text output is readable too.
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( Note that tracing self tests can't be enabled if this tracer is
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selected, because the self-tests are an initcall as well and that
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would invalidate the boot trace. )
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config STACK_TRACER
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bool "Trace max stack"
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depends on HAVE_FUNCTION_TRACER
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depends on DEBUG_KERNEL
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select FUNCTION_TRACER
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select STACKTRACE
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help
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This special tracer records the maximum stack footprint of the
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kernel and displays it in debugfs/tracing/stack_trace.
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This tracer works by hooking into every function call that the
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kernel executes, and keeping a maximum stack depth value and
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stack-trace saved. Because this logic has to execute in every
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kernel function, all the time, this option can slow down the
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kernel measurably and is generally intended for kernel
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developers only.
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Say N if unsure.
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config DYNAMIC_FTRACE
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bool "enable/disable ftrace tracepoints dynamically"
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depends on FUNCTION_TRACER
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depends on HAVE_DYNAMIC_FTRACE
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depends on DEBUG_KERNEL
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default y
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help
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This option will modify all the calls to ftrace dynamically
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(will patch them out of the binary image and replaces them
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with a No-Op instruction) as they are called. A table is
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created to dynamically enable them again.
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This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise
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has native performance as long as no tracing is active.
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The changes to the code are done by a kernel thread that
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wakes up once a second and checks to see if any ftrace calls
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were made. If so, it runs stop_machine (stops all CPUS)
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and modifies the code to jump over the call to ftrace.
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config FTRACE_MCOUNT_RECORD
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def_bool y
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depends on DYNAMIC_FTRACE
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depends on HAVE_FTRACE_MCOUNT_RECORD
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config FTRACE_SELFTEST
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bool
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config FTRACE_STARTUP_TEST
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bool "Perform a startup test on ftrace"
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depends on TRACING && DEBUG_KERNEL && !BOOT_TRACER
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select FTRACE_SELFTEST
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help
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This option performs a series of startup tests on ftrace. On bootup
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a series of tests are made to verify that the tracer is
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functioning properly. It will do tests on all the configured
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tracers of ftrace.
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endmenu
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