X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=init%2FKconfig;h=706728be312f5506a8d3fd20b51d33bf9186144e;hb=57c0c15b5244320065374ad2c54f4fbec77a6428;hp=3f7e60995c80714888df391cd8b91ef0f5982306;hpb=fc8e1ead9314cf0e0f1922e661428b93d3a50d88;p=deliverable%2Flinux.git diff --git a/init/Kconfig b/init/Kconfig index 3f7e60995c80..706728be312f 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -316,38 +316,28 @@ choice prompt "RCU Implementation" default TREE_RCU -config CLASSIC_RCU - bool "Classic RCU" - help - This option selects the classic RCU implementation that is - designed for best read-side performance on non-realtime - systems. - - Select this option if you are unsure. - config TREE_RCU bool "Tree-based hierarchical RCU" help This option selects the RCU implementation that is designed for very large SMP system with hundreds or - thousands of CPUs. + thousands of CPUs. It also scales down nicely to + smaller systems. -config PREEMPT_RCU - bool "Preemptible RCU" +config TREE_PREEMPT_RCU + bool "Preemptable tree-based hierarchical RCU" depends on PREEMPT help - This option reduces the latency of the kernel by making certain - RCU sections preemptible. Normally RCU code is non-preemptible, if - this option is selected then read-only RCU sections become - preemptible. This helps latency, but may expose bugs due to - now-naive assumptions about each RCU read-side critical section - remaining on a given CPU through its execution. + This option selects the RCU implementation that is + designed for very large SMP systems with hundreds or + thousands of CPUs, but for which real-time response + is also required. endchoice config RCU_TRACE bool "Enable tracing for RCU" - depends on TREE_RCU || PREEMPT_RCU + depends on TREE_RCU || TREE_PREEMPT_RCU help This option provides tracing in RCU which presents stats in debugfs for debugging RCU implementation. @@ -359,7 +349,7 @@ config RCU_FANOUT int "Tree-based hierarchical RCU fanout value" range 2 64 if 64BIT range 2 32 if !64BIT - depends on TREE_RCU + depends on TREE_RCU || TREE_PREEMPT_RCU default 64 if 64BIT default 32 if !64BIT help @@ -374,7 +364,7 @@ config RCU_FANOUT config RCU_FANOUT_EXACT bool "Disable tree-based hierarchical RCU auto-balancing" - depends on TREE_RCU + depends on TREE_RCU || TREE_PREEMPT_RCU default n help This option forces use of the exact RCU_FANOUT value specified, @@ -387,18 +377,12 @@ config RCU_FANOUT_EXACT Say N if unsure. config TREE_RCU_TRACE - def_bool RCU_TRACE && TREE_RCU + def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) select DEBUG_FS help - This option provides tracing for the TREE_RCU implementation, - permitting Makefile to trivially select kernel/rcutree_trace.c. - -config PREEMPT_RCU_TRACE - def_bool RCU_TRACE && PREEMPT_RCU - select DEBUG_FS - help - This option provides tracing for the PREEMPT_RCU implementation, - permitting Makefile to trivially select kernel/rcupreempt_trace.c. + This option provides tracing for the TREE_RCU and + TREE_PREEMPT_RCU implementations, permitting Makefile to + trivially select kernel/rcutree_trace.c. endmenu # "RCU Subsystem" @@ -931,31 +915,36 @@ config AIO by some high performance threaded applications. Disabling this option saves about 7k. -config HAVE_PERF_COUNTERS +config HAVE_PERF_EVENTS bool help See tools/perf/design.txt for details. -menu "Performance Counters" +menu "Kernel Performance Events And Counters" -config PERF_COUNTERS - bool "Kernel Performance Counters" - default y if PROFILING - depends on HAVE_PERF_COUNTERS +config PERF_EVENTS + bool "Kernel performance events and counters" + default y if (PROFILING || PERF_COUNTERS) + depends on HAVE_PERF_EVENTS select ANON_INODES help - Enable kernel support for performance counter hardware. + Enable kernel support for various performance events provided + by software and hardware. - Performance counters are special hardware registers available - on most modern CPUs. These registers count the number of certain + Software events are supported either build-in or via the + use of generic tracepoints. + + Most modern CPUs support performance events via performance + counter registers. These registers count the number of certain types of hw events: such as instructions executed, cachemisses suffered, or branches mis-predicted - without slowing down the kernel or applications. These registers can also trigger interrupts when a threshold number of events have passed - and can thus be used to profile the code that runs on that CPU. - The Linux Performance Counter subsystem provides an abstraction of - these hardware capabilities, available via a system call. It + The Linux Performance Event subsystem provides an abstraction of + these software and hardware cevent apabilities, available via a + system call and used by the "perf" utility in tools/perf/. It provides per task and per CPU counters, and it provides event capabilities on top of those. @@ -963,17 +952,29 @@ config PERF_COUNTERS config EVENT_PROFILE bool "Tracepoint profiling sources" - depends on PERF_COUNTERS && EVENT_TRACING + depends on PERF_EVENTS && EVENT_TRACING default y help - Allow the use of tracepoints as software performance counters. + Allow the use of tracepoints as software performance events. - When this is enabled, you can create perf counters based on + When this is enabled, you can create perf events based on tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID found in debugfs://tracing/events/*/*/id. (The -e/--events option to the perf tool can parse and interpret symbolic tracepoints, in the subsystem:tracepoint_name format.) +config PERF_COUNTERS + bool "Kernel performance counters (old config option)" + depends on HAVE_PERF_EVENTS + help + This config has been obsoleted by the PERF_EVENTS + config option - please see that one for details. + + It has no effect on the kernel whether you enable + it or not, it is a compatibility placeholder. + + Say N if unsure. + endmenu config VM_EVENT_COUNTERS