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Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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| Original file line number | Diff line number | Diff line change |
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@@ -48,6 +48,7 @@ dutil.h | |
| changes-v1.13 | ||
| changes-v1.16 | ||
| changes-v1.17 | ||
| changes-v1.18 | ||
| COPYING | ||
| NEWS | ||
| README | ||
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,117 @@ | ||
| v1.18: | ||
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| - Use type information to pretty print raw data from stdin, all | ||
| documented in the man pages, further information in the csets. | ||
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| TLDRish: this almost completely deciphers a perf.data file: | ||
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| $ pahole ~/bin/perf --header=perf_file_header \ | ||
| -C 'perf_file_attr(range=attrs),perf_event_header(range=data,sizeof,type,type_enum=perf_event_type+perf_user_event_type)' < perf.data | ||
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| What the above command line does: | ||
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| This will state that a 'struct perf_file_header' is available in BTF or DWARF | ||
| in the ~/bin/perf file and that at the start of stdin it should be used to decode | ||
| sizeof(struct perf_file_header) bytes, pretty printing it according to its members. | ||
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| Furthermore, that header can be referenced later in the command line, for instance | ||
| that 'range=data' means that in the header, it expects a 'range' member in | ||
| 'struct perf_file_header' to be used: | ||
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| $ pahole ~/bin/perf --header=perf_file_header < perf.data | ||
| { | ||
| .magic = 3622385352885552464, | ||
| .size = 104, | ||
| .attr_size = 136, | ||
| .attrs = { | ||
| .offset = 296, | ||
| .size = 136, | ||
| }, | ||
| .data = { | ||
| .offset = 432, | ||
| .size = 14688, | ||
| }, | ||
| .event_types = { | ||
| .offset = 0, | ||
| .size = 0, | ||
| }, | ||
| .adds_features = { 376537084, 0, 0, 0 }, | ||
| }, | ||
| $ | ||
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| That 'range' field is expected to have 'offset' and 'size' fields, so that | ||
| it can go on decoding a number of 'struct perf_event_header' entries. | ||
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| That 'sizeof' in turn expects that in 'struct perf_event_header' there is a | ||
| 'size' field stating how long that particular record is, one can also use | ||
| 'sizeof=some_other_member_name'. | ||
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| This supports variable sized records and then the 'type' field expects there | ||
| is a 'struct perf_event_type' member named 'type' (again, type=something_else | ||
| may be used. Finally, the value in the 'type' field is used to lookup an entry | ||
| in the set formed by the two enumerations specified in the 'type_enum=' argument. | ||
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| If we look at these enums we'll see that its entries have names that can be, | ||
| when lowercased, point to structs containing the layout for the variable sized | ||
| record, which allows it to cast and produce the right pretty printed output. | ||
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| I.e. using the kernel BTF info we get: | ||
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| $ pahole perf_event_type | ||
| enum perf_event_type { | ||
| PERF_RECORD_MMAP = 1, | ||
| PERF_RECORD_LOST = 2, | ||
| PERF_RECORD_COMM = 3, | ||
| PERF_RECORD_EXIT = 4, | ||
| PERF_RECORD_THROTTLE = 5, | ||
| PERF_RECORD_UNTHROTTLE = 6, | ||
| PERF_RECORD_FORK = 7, | ||
| PERF_RECORD_READ = 8, | ||
| PERF_RECORD_SAMPLE = 9, | ||
| PERF_RECORD_MMAP2 = 10, | ||
| PERF_RECORD_AUX = 11, | ||
| PERF_RECORD_ITRACE_START = 12, | ||
| PERF_RECORD_LOST_SAMPLES = 13, | ||
| PERF_RECORD_SWITCH = 14, | ||
| PERF_RECORD_SWITCH_CPU_WIDE = 15, | ||
| PERF_RECORD_NAMESPACES = 16, | ||
| PERF_RECORD_KSYMBOL = 17, | ||
| PERF_RECORD_BPF_EVENT = 18, | ||
| PERF_RECORD_CGROUP = 19, | ||
| PERF_RECORD_TEXT_POKE = 20, | ||
| PERF_RECORD_MAX = 21, | ||
| }; | ||
| $ | ||
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| That is the same as in ~/bin/perf, and, if we get one of these and ask for | ||
| that struct: | ||
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| $ pahole -C perf_record_mmap ~/bin/perf | ||
| struct perf_record_mmap { | ||
| struct perf_event_header header; /* 0 8 */ | ||
| __u32 pid; /* 8 4 */ | ||
| __u32 tid; /* 12 4 */ | ||
| __u64 start; /* 16 8 */ | ||
| __u64 len; /* 24 8 */ | ||
| __u64 pgoff; /* 32 8 */ | ||
| char filename[4096]; /* 40 4096 */ | ||
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| /* size: 4136, cachelines: 65, members: 7 */ | ||
| /* last cacheline: 40 bytes */ | ||
| }; | ||
| $ | ||
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| Many other options were introduced to work with this, including --count, | ||
| --skip, etc, look at the man page for details. | ||
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| - Store percpu variables in vmlinux BTF. This can be disabled when debugging | ||
| kernel features being developed to use it. | ||
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| - pahole now should be segfault free when handling gdb test suit DWARF | ||
| files, including ADA, FORTRAN, rust and dwp compressed files, the | ||
| later being just flatly refused, that got left for v1.19. | ||
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| - Bail out on partial units for now, avoiding segfaults and providing warning | ||
| to user, hopefully will be addressed in v1.19. | ||
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| Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> |
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@@ -2,7 +2,7 @@ | |
| %define libver 1 | ||
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| Name: dwarves | ||
| Version: 1.17 | ||
| Version: 1.18 | ||
| Release: 1%{?dist} | ||
| License: GPLv2 | ||
| Summary: Debugging Information Manipulation Tools (pahole & friends) | ||
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@@ -39,7 +39,13 @@ One example of pfunct usage is in the fullcircle tool, a shell that drivers | |
| pfunct to generate compileable code out of a .o file and then build it using | ||
| gcc, with the same compiler flags, and then use codiff to make sure the | ||
| original .o file and the new one generated from debug info produces the same | ||
| debug info. | ||
| debug info.pick | ||
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| Pahole also can be used to use all this type information to pretty print raw data | ||
| according to command line directions. | ||
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| Headers can have its data format described from debugging info and offsets from | ||
| it can be used to further format a number of records. | ||
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| The btfdiff utility compares the output of pahole from BTF and DWARF to make | ||
| sure they produce the same results. | ||
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@@ -73,7 +79,7 @@ rm -Rf %{buildroot} | |
| %files | ||
| %doc README.ctracer | ||
| %doc README.btf | ||
| %doc changes-v1.17 | ||
| %doc changes-v1.18 | ||
| %doc NEWS | ||
| %{_bindir}/btfdiff | ||
| %{_bindir}/codiff | ||
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@@ -128,6 +134,13 @@ rm -Rf %{buildroot} | |
| %{_libdir}/%{libname}_reorganize.so | ||
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| %changelog | ||
| * Fri Oct 02 2020 Arnaldo Carvalho de Melo <[email protected]> - 1.18-1 | ||
| - New release: 1.18 | ||
| - Use debugging info to pretty print raw data | ||
| - Store percpu variables in vmlinux BTF. | ||
| - Fixes to address segfaults on the gdb testsuite binaries | ||
| - Bail out on partial units for now, avoiding segfaults and providing warning to user. | ||
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| * Fri Mar 13 2020 Arnaldo Carvalho de Melo <[email protected]> - 1.17-1 | ||
| - New release: 1.17 | ||
| - Support raw BTF as available in /sys/kernel/btf/vmlinux. | ||
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