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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
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
Ingo Molnar8446f1d2005-09-06 15:16:27 -070049config DETECT_SOFTLOCKUP
50 bool "Detect Soft Lockups"
51 depends on DEBUG_KERNEL
52 default y
53 help
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
57 chance to run.
58
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
62 overhead.
63
64 (Note that "hard lockups" are separate type of bugs that
65 can be detected via the NMI-watchdog, on platforms that
66 support it.)
67
Linus Torvalds1da177e2005-04-16 15:20:36 -070068config SCHEDSTATS
69 bool "Collect scheduler statistics"
70 depends on DEBUG_KERNEL && PROC_FS
71 help
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
78 this adds.
79
80config DEBUG_SLAB
81 bool "Debug memory allocations"
82 depends on DEBUG_KERNEL
83 help
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.
87
88config DEBUG_PREEMPT
89 bool "Debug preemptible kernel"
90 depends on DEBUG_KERNEL && PREEMPT
91 default y
92 help
93 If you say Y here then the kernel will use a debug variant of the
94 commonly used smp_processor_id() function and will print warnings
95 if kernel code uses it in a preemption-unsafe way. Also, the kernel
96 will detect preemption count underflows.
97
98config DEBUG_SPINLOCK
99 bool "Spinlock debugging"
100 depends on DEBUG_KERNEL
101 help
102 Say Y here and build SMP to catch missing spinlock initialization
103 and certain other kinds of spinlock errors commonly made. This is
104 best used in conjunction with the NMI watchdog so that spinlock
105 deadlocks are also debuggable.
106
107config DEBUG_SPINLOCK_SLEEP
108 bool "Sleep-inside-spinlock checking"
109 depends on DEBUG_KERNEL
110 help
111 If you say Y here, various routines which may sleep will become very
112 noisy if they are called with a spinlock held.
113
114config DEBUG_KOBJECT
115 bool "kobject debugging"
116 depends on DEBUG_KERNEL
117 help
118 If you say Y here, some extra kobject debugging messages will be sent
119 to the syslog.
120
121config DEBUG_HIGHMEM
122 bool "Highmem debugging"
123 depends on DEBUG_KERNEL && HIGHMEM
124 help
125 This options enables addition error checking for high memory systems.
126 Disable for production systems.
127
128config DEBUG_BUGVERBOSE
129 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700130 depends on BUG
Brian Gerst0d078f62005-10-30 14:59:20 -0800131 depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 default !EMBEDDED
133 help
134 Say Y here to make BUG() panics output the file name and line number
135 of the BUG call as well as the EIP and oops trace. This aids
136 debugging but costs about 70-100K of memory.
137
138config DEBUG_INFO
139 bool "Compile the kernel with debug info"
140 depends on DEBUG_KERNEL
141 help
142 If you say Y here the resulting kernel image will include
143 debugging info resulting in a larger kernel image.
144 Say Y here only if you plan to debug the kernel.
145
146 If unsure, say N.
147
148config DEBUG_IOREMAP
149 bool "Enable ioremap() debugging"
150 depends on DEBUG_KERNEL && PARISC
151 help
152 Enabling this option will cause the kernel to distinguish between
153 ioremapped and physical addresses. It will print a backtrace (at
154 most one every 10 seconds), hopefully allowing you to see which
155 drivers need work. Fixing all these problems is a prerequisite
156 for turning on USE_HPPA_IOREMAP. The warnings are harmless;
157 the kernel has enough information to fix the broken drivers
158 automatically, but we'd like to make it more efficient by not
159 having to do that.
160
161config DEBUG_FS
162 bool "Debug Filesystem"
Adrian Bunk3348e052005-07-29 12:14:28 -0700163 depends on DEBUG_KERNEL && SYSFS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 help
165 debugfs is a virtual file system that kernel developers use to put
166 debugging files into. Enable this option to be able to read and
167 write to these files.
168
169 If unsure, say N.
170
171config FRAME_POINTER
172 bool "Compile the kernel with frame pointers"
Andi Kleenaeb39982005-09-12 18:49:25 +0200173 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700174 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 help
176 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800177 and slower, but it might give very useful debugging information on
178 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200179 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180