3 bool "Show timing information on printks"
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
13 bool "Magic SysRq key"
16 If you say Y here, you will have some control over the system even
17 if the system crashes for example during kernel debugging (e.g., you
18 will be able to flush the buffer cache to disk, reboot the system
19 immediately or dump some status information). This is accomplished
20 by pressing various keys while holding SysRq (Alt+PrintScreen). It
21 also works on a serial console (on PC hardware at least), if you
22 send a BREAK and then within 5 seconds a command keypress. The
23 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
24 unless you really know what this hack does.
27 bool "Kernel debugging"
29 Say Y here if you are developing drivers or trying to debug and
30 identify kernel problems.
33 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
36 default 16 if X86_NUMAQ || IA64
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
45 14 => 16 KB for uniprocessor
49 config DETECT_SOFTLOCKUP
50 bool "Detect Soft Lockups"
51 depends on DEBUG_KERNEL
54 Say Y here to enable the kernel to detect "soft lockups",
55 which are bugs that cause the kernel to loop in kernel
56 mode for more than 10 seconds, without giving other tasks a
59 When a soft-lockup is detected, the kernel will print the
60 current stack trace (which you should report), but the
61 system will stay locked up. This feature has negligible
64 (Note that "hard lockups" are separate type of bugs that
65 can be detected via the NMI-watchdog, on platforms that
69 bool "Collect scheduler statistics"
70 depends on DEBUG_KERNEL && PROC_FS
72 If you say Y here, additional code will be inserted into the
73 scheduler and related routines to collect statistics about
74 scheduler behavior and provide them in /proc/schedstat. These
75 stats may be useful for both tuning and debugging the scheduler
76 If you aren't debugging the scheduler or trying to tune a specific
77 application, you can say N to avoid the very slight overhead
81 bool "Debug slab memory allocations"
82 depends on DEBUG_KERNEL && SLAB
84 Say Y here to have the kernel do limited verification on memory
85 allocation as well as poisoning memory on free to catch use of freed
86 memory. This can make kmalloc/kfree-intensive workloads much slower.
88 config DEBUG_SLAB_LEAK
89 bool "Memory leak debugging"
93 bool "Debug preemptible kernel"
94 depends on DEBUG_KERNEL && PREEMPT
97 If you say Y here then the kernel will use a debug variant of the
98 commonly used smp_processor_id() function and will print warnings
99 if kernel code uses it in a preemption-unsafe way. Also, the kernel
100 will detect preemption count underflows.
103 bool "Mutex debugging, deadlock detection"
105 depends on DEBUG_KERNEL
107 This allows mutex semantics violations and mutex related deadlocks
108 (lockups) to be detected and reported automatically.
110 config DEBUG_RT_MUTEXES
111 bool "RT Mutex debugging, deadlock detection"
113 depends on DEBUG_KERNEL && RT_MUTEXES
115 This allows rt mutex semantics violations and rt mutex related
116 deadlocks (lockups) to be detected and reported automatically.
121 depends on DEBUG_RT_MUTEXES
123 config RT_MUTEX_TESTER
124 bool "Built-in scriptable tester for rt-mutexes"
125 depends on RT_MUTEXES
128 This option enables a rt-mutex tester.
130 config DEBUG_SPINLOCK
131 bool "Spinlock debugging"
132 depends on DEBUG_KERNEL
134 Say Y here and build SMP to catch missing spinlock initialization
135 and certain other kinds of spinlock errors commonly made. This is
136 best used in conjunction with the NMI watchdog so that spinlock
137 deadlocks are also debuggable.
139 config DEBUG_SPINLOCK_SLEEP
140 bool "Sleep-inside-spinlock checking"
141 depends on DEBUG_KERNEL
143 If you say Y here, various routines which may sleep will become very
144 noisy if they are called with a spinlock held.
147 bool "kobject debugging"
148 depends on DEBUG_KERNEL
150 If you say Y here, some extra kobject debugging messages will be sent
154 bool "Highmem debugging"
155 depends on DEBUG_KERNEL && HIGHMEM
157 This options enables addition error checking for high memory systems.
158 Disable for production systems.
160 config DEBUG_BUGVERBOSE
161 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
163 depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
166 Say Y here to make BUG() panics output the file name and line number
167 of the BUG call as well as the EIP and oops trace. This aids
168 debugging but costs about 70-100K of memory.
171 bool "Compile the kernel with debug info"
172 depends on DEBUG_KERNEL
174 If you say Y here the resulting kernel image will include
175 debugging info resulting in a larger kernel image.
176 Say Y here only if you plan to debug the kernel.
181 bool "Debug Filesystem"
184 debugfs is a virtual file system that kernel developers use to put
185 debugging files into. Enable this option to be able to read and
186 write to these files.
192 depends on DEBUG_KERNEL
194 Enable this to turn on extended checks in the virtual-memory system
195 that may impact performance.
200 bool "Compile the kernel with frame pointers"
201 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
202 default y if DEBUG_INFO && UML
204 If you say Y here the resulting kernel image will be slightly larger
205 and slower, but it might give very useful debugging information on
206 some architectures or if you use external debuggers.
207 If you don't debug the kernel, you can say N.
210 bool "Compile the kernel with frame unwind information"
211 depends on !IA64 && !PARISC
212 depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
214 If you say Y here the resulting kernel image will be slightly larger
215 but not slower, and it will give very useful debugging information.
216 If you don't debug the kernel, you can say N, but we may not be able
217 to solve problems without frame unwind information or frame pointers.
220 bool "Stack unwind support"
221 depends on UNWIND_INFO
224 This enables more precise stack traces, omitting all unrelated
225 occurrences of pointers into kernel code from the dump.
227 config FORCED_INLINING
228 bool "Force gcc to inline functions marked 'inline'"
229 depends on DEBUG_KERNEL
232 This option determines if the kernel forces gcc to inline the functions
233 developers have marked 'inline'. Doing so takes away freedom from gcc to
234 do what it thinks is best, which is desirable for the gcc 3.x series of
235 compilers. The gcc 4.x series have a rewritten inlining algorithm and
236 disabling this option will generate a smaller kernel there. Hopefully
237 this algorithm is so good that allowing gcc4 to make the decision can
238 become the default in the future, until then this option is there to
241 config RCU_TORTURE_TEST
242 tristate "torture tests for RCU"
243 depends on DEBUG_KERNEL
246 This option provides a kernel module that runs torture tests
247 on the RCU infrastructure. The kernel module may be built
248 after the fact on the running kernel to be tested, if desired.
250 Say Y here if you want RCU torture tests to start automatically
251 at boot time (you probably don't).
252 Say M if you want the RCU torture tests to build as a module.
253 Say N if you are unsure.