116444a8aSArnaldo Carvalho de Melo# 216444a8aSArnaldo Carvalho de Melo# Architectures that offer an FTRACE implementation should select HAVE_FTRACE: 316444a8aSArnaldo Carvalho de Melo# 416444a8aSArnaldo Carvalho de Meloconfig HAVE_FTRACE 516444a8aSArnaldo Carvalho de Melo bool 6bc0c38d1SSteven Rostedt 7352ad25aSSteven Rostedtconfig TRACER_MAX_TRACE 8352ad25aSSteven Rostedt bool 9352ad25aSSteven Rostedt 10bc0c38d1SSteven Rostedtconfig TRACING 11bc0c38d1SSteven Rostedt bool 12bc0c38d1SSteven Rostedt select DEBUG_FS 13bc0c38d1SSteven Rostedt 141b29b018SSteven Rostedtconfig FTRACE 151b29b018SSteven Rostedt bool "Kernel Function Tracer" 161b29b018SSteven Rostedt depends on DEBUG_KERNEL && HAVE_FTRACE 171b29b018SSteven Rostedt select FRAME_POINTER 181b29b018SSteven Rostedt select TRACING 1935e8e302SSteven Rostedt select CONTEXT_SWITCH_TRACER 201b29b018SSteven Rostedt help 211b29b018SSteven Rostedt Enable the kernel to trace every kernel function. This is done 221b29b018SSteven Rostedt by using a compiler feature to insert a small, 5-byte No-Operation 231b29b018SSteven Rostedt instruction to the beginning of every kernel function, which NOP 241b29b018SSteven Rostedt sequence is then dynamically patched into a tracer call when 251b29b018SSteven Rostedt tracing is enabled by the administrator. If it's runtime disabled 261b29b018SSteven Rostedt (the bootup default), then the overhead of the instructions is very 271b29b018SSteven Rostedt small and not measurable even in micro-benchmarks. 2835e8e302SSteven Rostedt 2981d68a96SSteven Rostedtconfig IRQSOFF_TRACER 3081d68a96SSteven Rostedt bool "Interrupts-off Latency Tracer" 3181d68a96SSteven Rostedt default n 3281d68a96SSteven Rostedt depends on TRACE_IRQFLAGS_SUPPORT 3381d68a96SSteven Rostedt depends on GENERIC_TIME 3481d68a96SSteven Rostedt select TRACE_IRQFLAGS 3581d68a96SSteven Rostedt select TRACING 3681d68a96SSteven Rostedt select TRACER_MAX_TRACE 3781d68a96SSteven Rostedt help 3881d68a96SSteven Rostedt This option measures the time spent in irqs-off critical 3981d68a96SSteven Rostedt sections, with microsecond accuracy. 4081d68a96SSteven Rostedt 4181d68a96SSteven Rostedt The default measurement method is a maximum search, which is 4281d68a96SSteven Rostedt disabled by default and can be runtime (re-)started 4381d68a96SSteven Rostedt via: 4481d68a96SSteven Rostedt 4581d68a96SSteven Rostedt echo 0 > /debugfs/tracing/tracing_max_latency 4681d68a96SSteven Rostedt 47*6cd8a4bbSSteven Rostedt (Note that kernel size and overhead increases with this option 48*6cd8a4bbSSteven Rostedt enabled. This option and the preempt-off timing option can be 49*6cd8a4bbSSteven Rostedt used together or separately.) 50*6cd8a4bbSSteven Rostedt 51*6cd8a4bbSSteven Rostedtconfig PREEMPT_TRACER 52*6cd8a4bbSSteven Rostedt bool "Preemption-off Latency Tracer" 53*6cd8a4bbSSteven Rostedt default n 54*6cd8a4bbSSteven Rostedt depends on GENERIC_TIME 55*6cd8a4bbSSteven Rostedt depends on PREEMPT 56*6cd8a4bbSSteven Rostedt select TRACING 57*6cd8a4bbSSteven Rostedt select TRACER_MAX_TRACE 58*6cd8a4bbSSteven Rostedt help 59*6cd8a4bbSSteven Rostedt This option measures the time spent in preemption off critical 60*6cd8a4bbSSteven Rostedt sections, with microsecond accuracy. 61*6cd8a4bbSSteven Rostedt 62*6cd8a4bbSSteven Rostedt The default measurement method is a maximum search, which is 63*6cd8a4bbSSteven Rostedt disabled by default and can be runtime (re-)started 64*6cd8a4bbSSteven Rostedt via: 65*6cd8a4bbSSteven Rostedt 66*6cd8a4bbSSteven Rostedt echo 0 > /debugfs/tracing/tracing_max_latency 67*6cd8a4bbSSteven Rostedt 68*6cd8a4bbSSteven Rostedt (Note that kernel size and overhead increases with this option 69*6cd8a4bbSSteven Rostedt enabled. This option and the irqs-off timing option can be 70*6cd8a4bbSSteven Rostedt used together or separately.) 71*6cd8a4bbSSteven Rostedt 72352ad25aSSteven Rostedtconfig SCHED_TRACER 73352ad25aSSteven Rostedt bool "Scheduling Latency Tracer" 74352ad25aSSteven Rostedt depends on DEBUG_KERNEL 75352ad25aSSteven Rostedt select TRACING 76352ad25aSSteven Rostedt select CONTEXT_SWITCH_TRACER 77352ad25aSSteven Rostedt select TRACER_MAX_TRACE 78352ad25aSSteven Rostedt help 79352ad25aSSteven Rostedt This tracer tracks the latency of the highest priority task 80352ad25aSSteven Rostedt to be scheduled in, starting from the point it has woken up. 81352ad25aSSteven Rostedt 8235e8e302SSteven Rostedtconfig CONTEXT_SWITCH_TRACER 8335e8e302SSteven Rostedt bool "Trace process context switches" 8435e8e302SSteven Rostedt depends on DEBUG_KERNEL 8535e8e302SSteven Rostedt select TRACING 8635e8e302SSteven Rostedt select MARKERS 8735e8e302SSteven Rostedt help 8835e8e302SSteven Rostedt This tracer gets called from the context switch and records 8935e8e302SSteven Rostedt all switching of tasks. 9035e8e302SSteven Rostedt 91