1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 menu "GCOV-based kernel profiling" 2 menu "GCOV-based kernel profiling"
3 3
4 config GCOV_KERNEL 4 config GCOV_KERNEL
5 bool "Enable gcov-based kernel profili 5 bool "Enable gcov-based kernel profiling"
6 depends on DEBUG_FS 6 depends on DEBUG_FS
7 depends on !ARCH_WANTS_NO_INSTR || CC_ 7 depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR
8 select CONSTRUCTORS 8 select CONSTRUCTORS
9 default n 9 default n
10 help 10 help
11 This option enables gcov-based code pr 11 This option enables gcov-based code profiling (e.g. for code coverage
12 measurements). 12 measurements).
13 13
14 If unsure, say N. 14 If unsure, say N.
15 15
16 Additionally specify CONFIG_GCOV_PROFI 16 Additionally specify CONFIG_GCOV_PROFILE_ALL=y to get profiling data
17 for the entire kernel. To enable profi 17 for the entire kernel. To enable profiling for specific files or
18 directories, add a line similar to the 18 directories, add a line similar to the following to the respective
19 Makefile: 19 Makefile:
20 20
21 For a single file (e.g. main.o): 21 For a single file (e.g. main.o):
22 GCOV_PROFILE_main.o := y 22 GCOV_PROFILE_main.o := y
23 23
24 For all files in one directory: 24 For all files in one directory:
25 GCOV_PROFILE := y 25 GCOV_PROFILE := y
26 26
27 To exclude files from being profiled e 27 To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
28 is specified, use: 28 is specified, use:
29 29
30 GCOV_PROFILE_main.o := n 30 GCOV_PROFILE_main.o := n
31 and: 31 and:
32 GCOV_PROFILE := n 32 GCOV_PROFILE := n
33 33
34 Note that the debugfs filesystem has t 34 Note that the debugfs filesystem has to be mounted to access
35 profiling data. 35 profiling data.
36 36
37 config ARCH_HAS_GCOV_PROFILE_ALL 37 config ARCH_HAS_GCOV_PROFILE_ALL
38 def_bool n 38 def_bool n
39 39
40 config GCOV_PROFILE_ALL 40 config GCOV_PROFILE_ALL
41 bool "Profile entire Kernel" 41 bool "Profile entire Kernel"
42 depends on !COMPILE_TEST 42 depends on !COMPILE_TEST
43 depends on GCOV_KERNEL 43 depends on GCOV_KERNEL
44 depends on ARCH_HAS_GCOV_PROFILE_ALL 44 depends on ARCH_HAS_GCOV_PROFILE_ALL
45 default n 45 default n
46 help 46 help
47 This options activates profiling for t 47 This options activates profiling for the entire kernel.
48 48
49 If unsure, say N. 49 If unsure, say N.
50 50
51 Note that a kernel compiled with profi 51 Note that a kernel compiled with profiling flags will be significantly
52 larger and run slower. Also be sure to 52 larger and run slower. Also be sure to exclude files from profiling
53 which are not linked to the kernel ima 53 which are not linked to the kernel image to prevent linker errors.
54 54
55 endmenu 55 endmenu
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