1 2config PRINTK_TIME 3 bool "Show timing information on printks" 4 help 5 Selecting this option causes timing information to be 6 included in printk output. This allows you to measure 7 the interval between kernel operations, including bootup 8 operations. This is useful for identifying long delays 9 in kernel startup. 10 11 12config DEBUG_KERNEL 13 bool "Kernel debugging" 14 help 15 Say Y here if you are developing drivers or trying to debug and 16 identify kernel problems. 17 18config MAGIC_SYSRQ 19 bool "Magic SysRq key" 20 depends on DEBUG_KERNEL && !UML 21 help 22 If you say Y here, you will have some control over the system even 23 if the system crashes for example during kernel debugging (e.g., you 24 will be able to flush the buffer cache to disk, reboot the system 25 immediately or dump some status information). This is accomplished 26 by pressing various keys while holding SysRq (Alt+PrintScreen). It 27 also works on a serial console (on PC hardware at least), if you 28 send a BREAK and then within 5 seconds a command keypress. The 29 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y 30 unless you really know what this hack does. 31 32config LOG_BUF_SHIFT 33 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL 34 range 12 21 35 default 17 if ARCH_S390 36 default 16 if X86_NUMAQ || IA64 37 default 15 if SMP 38 default 14 39 help 40 Select kernel log buffer size as a power of 2. 41 Defaults and Examples: 42 17 => 128 KB for S/390 43 16 => 64 KB for x86 NUMAQ or IA-64 44 15 => 32 KB for SMP 45 14 => 16 KB for uniprocessor 46 13 => 8 KB 47 12 => 4 KB 48 49config SCHEDSTATS 50 bool "Collect scheduler statistics" 51 depends on DEBUG_KERNEL && PROC_FS 52 help 53 If you say Y here, additional code will be inserted into the 54 scheduler and related routines to collect statistics about 55 scheduler behavior and provide them in /proc/schedstat. These 56 stats may be useful for both tuning and debugging the scheduler 57 If you aren't debugging the scheduler or trying to tune a specific 58 application, you can say N to avoid the very slight overhead 59 this adds. 60 61config DEBUG_SLAB 62 bool "Debug memory allocations" 63 depends on DEBUG_KERNEL 64 help 65 Say Y here to have the kernel do limited verification on memory 66 allocation as well as poisoning memory on free to catch use of freed 67 memory. This can make kmalloc/kfree-intensive workloads much slower. 68 69config DEBUG_PREEMPT 70 bool "Debug preemptible kernel" 71 depends on DEBUG_KERNEL && PREEMPT 72 default y 73 help 74 If you say Y here then the kernel will use a debug variant of the 75 commonly used smp_processor_id() function and will print warnings 76 if kernel code uses it in a preemption-unsafe way. Also, the kernel 77 will detect preemption count underflows. 78 79config DEBUG_SPINLOCK 80 bool "Spinlock debugging" 81 depends on DEBUG_KERNEL 82 help 83 Say Y here and build SMP to catch missing spinlock initialization 84 and certain other kinds of spinlock errors commonly made. This is 85 best used in conjunction with the NMI watchdog so that spinlock 86 deadlocks are also debuggable. 87 88config DEBUG_SPINLOCK_SLEEP 89 bool "Sleep-inside-spinlock checking" 90 depends on DEBUG_KERNEL 91 help 92 If you say Y here, various routines which may sleep will become very 93 noisy if they are called with a spinlock held. 94 95config DEBUG_KOBJECT 96 bool "kobject debugging" 97 depends on DEBUG_KERNEL 98 help 99 If you say Y here, some extra kobject debugging messages will be sent 100 to the syslog. 101 102config DEBUG_HIGHMEM 103 bool "Highmem debugging" 104 depends on DEBUG_KERNEL && HIGHMEM 105 help 106 This options enables addition error checking for high memory systems. 107 Disable for production systems. 108 109config DEBUG_BUGVERBOSE 110 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED 111 depends on BUG 112 depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || (X86 && !X86_64) || FRV 113 default !EMBEDDED 114 help 115 Say Y here to make BUG() panics output the file name and line number 116 of the BUG call as well as the EIP and oops trace. This aids 117 debugging but costs about 70-100K of memory. 118 119config DEBUG_INFO 120 bool "Compile the kernel with debug info" 121 depends on DEBUG_KERNEL 122 help 123 If you say Y here the resulting kernel image will include 124 debugging info resulting in a larger kernel image. 125 Say Y here only if you plan to debug the kernel. 126 127 If unsure, say N. 128 129config DEBUG_IOREMAP 130 bool "Enable ioremap() debugging" 131 depends on DEBUG_KERNEL && PARISC 132 help 133 Enabling this option will cause the kernel to distinguish between 134 ioremapped and physical addresses. It will print a backtrace (at 135 most one every 10 seconds), hopefully allowing you to see which 136 drivers need work. Fixing all these problems is a prerequisite 137 for turning on USE_HPPA_IOREMAP. The warnings are harmless; 138 the kernel has enough information to fix the broken drivers 139 automatically, but we'd like to make it more efficient by not 140 having to do that. 141 142config DEBUG_FS 143 bool "Debug Filesystem" 144 depends on DEBUG_KERNEL 145 help 146 debugfs is a virtual file system that kernel developers use to put 147 debugging files into. Enable this option to be able to read and 148 write to these files. 149 150 If unsure, say N. 151 152config FRAME_POINTER 153 bool "Compile the kernel with frame pointers" 154 depends on DEBUG_KERNEL && ((X86 && !X86_64) || CRIS || M68K || M68KNOMMU || FRV) 155 help 156 If you say Y here the resulting kernel image will be slightly larger 157 and slower, but it will give very useful debugging information. 158 If you don't debug the kernel, you can say N, but we may not be able 159 to solve problems without frame pointers. 160 161