kernel/linux.git/tools/perf/util/annotate.h, branch v5.9.2

perf tools: Replace zero-length array with flexible-array

2020-05-28T13:03:27+00:00

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Gustavo A. R. Silva Cc: Ian Rogers Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20200515172926.GA31976@embeddedor Signed-off-by: Arnaldo Carvalho de Melo

perf report: Support interactive annotation of code without symbols

2020-03-24T12:36:33+00:00

For perf report on stripped binaries it is currently impossible to do annotation. The annotation state is all tied to symbols, but there are either no symbols, or symbols are not covering all the code. We should support the annotation functionality even without symbols. This patch fakes a symbol and the symbol name is the string of address. After that, we just follow current annotation working flow. For example, 1. perf report Overhead Command Shared Object Symbol 20.67% div libc-2.27.so [.] __random_r 17.29% div libc-2.27.so [.] __random 10.59% div div [.] 0x0000000000000628 9.25% div div [.] 0x0000000000000612 6.11% div div [.] 0x0000000000000645 2. Select the line of "10.59% div div [.] 0x0000000000000628" and ENTER. Annotate 0x0000000000000628 Zoom into div thread Zoom into div DSO (use the 'k' hotkey to zoom directly into the kernel) Browse map details Run scripts for samples of symbol [0x0000000000000628] Run scripts for all samples Switch to another data file in PWD Exit 3. Select the "Annotate 0x0000000000000628" and ENTER. Percent│ │ │ │ Disassembly of section .text: │ │ 0000000000000628 <.text+0x68>: │ divsd %xmm4,%xmm0 │ divsd %xmm3,%xmm1 │ movsd (%rsp),%xmm2 │ addsd %xmm1,%xmm0 │ addsd %xmm2,%xmm0 │ movsd %xmm0,(%rsp) Now we can see the dump of object starting from 0x628. v5: --- Remove the hotkey 'a' implementation from this patch. It will be moved to a separate patch. v4: --- 1. Support the hotkey 'a'. When we press 'a' on address, now it supports the annotation. 2. Change the patch title from "Support interactive annotation of code without symbols" to "perf report: Support interactive annotation of code without symbols" v3: --- Keep just the ANNOTATION_DUMMY_LEN, and remove the opts->annotate_dummy_len since it's the "maybe in future we will provide" feature. v2: --- Fix a crash issue when annotating an address in "unknown" object. The steps to reproduce this issue: perf record -e cycles:u ls perf report 75.29% ls ld-2.27.so [.] do_lookup_x 23.64% ls ld-2.27.so [.] __GI___tunables_init 1.04% ls [unknown] [k] 0xffffffff85c01210 0.03% ls ld-2.27.so [.] _start When annotating 0xffffffff85c01210, the crash happens. v2 adds checking for ms->map in add_annotate_opt(). If the object is "unknown", ms->map is NULL. Committer notes: Renamed new_annotate_sym() to symbol__new_unresolved(). Use PRIx64 to fix this issue in some 32-bit arches: ui/browsers/hists.c: In function 'symbol__new_unresolved': ui/browsers/hists.c:2474:38: error: format '%lx' expects argument of type 'long unsigned int', but argument 5 has type 'u64' {aka 'long long unsigned int'} [-Werror=format=] snprintf(name, sizeof(name), "%-#.*lx", BITS_PER_LONG / 4, addr); ~~~~~~^ ~~~~ %-#.*llx Signed-off-by: Jin Yao Tested-by: Arnaldo Carvalho de Melo Tested-by: Ravi Bangoria Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: Kan Liang Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20200227043939.4403-3-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Get rid of annotation->nr_jumps

2020-03-04T13:34:10+00:00

The 'nr_jumps' field in 'struct annotation' is not used since it's inception in commit 2402e4a936a0 ("perf annotate browser: Show 'jumpy' functions"). Get rid of it. Signed-off-by: Ravi Bangoria Acked-by: Jiri Olsa Cc: Ian Rogers Cc: Jin Yao Cc: Namhyung Kim Cc: Song Liu Link: http://lore.kernel.org/lkml/20200204045233.474937-7-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Simplify disasm_line allocation and freeing code

2020-02-27T14:07:13+00:00

We are allocating disasm_line object in annotation_line__new() instead of disasm_line__new(). Similarly annotation_line__delete() is actually freeing disasm_line object as well. This complexity is because of privsize. But we don't need privsize anymore so get rid of privsize and simplify disasm_line allocation and freeing code. Signed-off-by: Ravi Bangoria Acked-by: Jiri Olsa Cc: Ian Rogers Cc: Jin Yao Cc: Namhyung Kim Cc: Song Liu Link: http://lore.kernel.org/lkml/20200204045233.474937-3-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Remove privsize from symbol__annotate() args

2020-02-27T14:06:14+00:00

privsize is passed as 0 from all the symbol__annotate() callers. Remove it from argument list. Signed-off-by: Ravi Bangoria Acked-by: Jiri Olsa Cc: Ian Rogers Cc: Jin Yao Cc: Namhyung Kim Cc: Song Liu Link: http://lore.kernel.org/lkml/20200204045233.474937-2-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Make perf config effective

2020-02-27T13:44:59+00:00

perf default config set by user in [annotate] section is totally ignored by annotate code. Fix it. Before: $ ./perf config annotate.hide_src_code=true annotate.show_nr_jumps=true annotate.show_nr_samples=true $ ./perf annotate shash │ unsigned h = 0; │ movl $0x0,-0xc(%rbp) │ while (*s) │ ↓ jmp 44 │ h = 65599 * h + *s++; 11.33 │24: mov -0xc(%rbp),%eax 43.50 │ imul $0x1003f,%eax,%ecx │ mov -0x18(%rbp),%rax After: │ movl $0x0,-0xc(%rbp) │ ↓ jmp 44 1 │1 24: mov -0xc(%rbp),%eax 4 │ imul $0x1003f,%eax,%ecx │ mov -0x18(%rbp),%rax Note that we have removed show_nr_samples and show_total_period from annotation_options because they are not used. Instead of them we use symbol_conf.show_nr_samples and symbol_conf.show_total_period. Committer testing: Using 'perf annotate --stdio2' to use the TUI rendering but emitting the output to stdio: # perf config # # perf config annotate.hide_src_code=true # perf config annotate.hide_src_code=true # # perf config annotate.show_nr_jumps=true # perf config annotate.show_nr_samples=true # perf config annotate.hide_src_code=true annotate.show_nr_jumps=true annotate.show_nr_samples=true # # Before: # perf annotate --stdio2 ObjectInstance::weak_pointer_was_finalized Samples: 1 of event 'cycles', 4000 Hz, Event count (approx.): 830873, [percent: local period] ObjectInstance::weak_pointer_was_finalized() /usr/lib64/libgjs.so.0.0.0 Percent 00000000000609f0 : endbr64 cmpq $0x0,0x20(%rdi) ↓ je 10 xor %eax,%eax ← retq xchg %ax,%ax 100.00 10: push %rbp cmpq $0x0,0x18(%rdi) mov %rdi,%rbp ↓ jne 20 1b: xor %eax,%eax pop %rbp ← retq nop 20: lea 0x18(%rdi),%rdi → callq JS_UpdateWeakPointerAfterGC(JS::Heap /dev/null Samples: 1 of event 'cycles', 4000 Hz, Event count (approx.): 830873, [percent: local period] ObjectInstance::weak_pointer_was_finalized() /usr/lib64/libgjs.so.0.0.0 Samples endbr64 cmpq $0x0,0x20(%rdi) ↓ je 10 xor %eax,%eax ← retq xchg %ax,%ax 1 1 10: push %rbp cmpq $0x0,0x18(%rdi) mov %rdi,%rbp ↓ jne 20 1 1b: xor %eax,%eax pop %rbp ← retq nop 1 20: lea 0x18(%rdi),%rdi → callq JS_UpdateWeakPointerAfterGC(JS::Heap /dev/null Samples: 1 of event 'cycles', 4000 Hz, Event count (approx.): 830873, [percent: local period] ObjectInstance::weak_pointer_was_finalized() /usr/lib64/libgjs.so.0.0.0 Samples endbr64 cmpq $0x0,0x20(%rdi) ↓ je 10 xor %eax,%eax ← retq xchg %ax,%ax 1 10: push %rbp cmpq $0x0,0x18(%rdi) mov %rdi,%rbp ↓ jne 20 1b: xor %eax,%eax pop %rbp ← retq nop 20: lea 0x18(%rdi),%rdi → callq JS_UpdateWeakPointerAfterGC(JS::Heap Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexey Budankov Cc: Changbin Du Cc: Ian Rogers Cc: Jin Yao Cc: Jiri Olsa Cc: Leo Yan Cc: Namhyung Kim Cc: Song Liu Cc: Taeung Song Cc: Thomas Richter Cc: Yisheng Xie Link: http://lore.kernel.org/lkml/20200213064306.160480-6-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Fix --show-total-period for tui/stdio2

2020-02-27T13:44:40+00:00

perf annotate --show-total-period does not really show total period. The reason is we have two separate variables for the same purpose. One is in symbol_conf.show_total_period and another is annotation_options.show_total_period. We save command line option in symbol_conf.show_total_period but uses annotation_option.show_total_period while rendering tui/stdio2 browser. Though, we copy symbol_conf.show_total_period to annotation__default_options.show_total_period but that is not really effective as we don't use annotation__default_options once we copy default options to dynamic variable annotate.opts in cmd_annotate(). Instead of all these complication, keep only one variable and use it all over. symbol_conf.show_total_period is used by perf report/top as well. So let's kill annotation_options.show_total_period. On a side note, I've kept annotation_options.show_total_period definition because it's still used by perf-config code. Follow up patch to fix perf-config for annotate will remove annotation_options.show_total_period. Signed-off-by: Ravi Bangoria Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexey Budankov Cc: Changbin Du Cc: Ian Rogers Cc: Jin Yao Cc: Jiri Olsa Cc: Leo Yan Cc: Namhyung Kim Cc: Song Liu Cc: Taeung Song Cc: Thomas Richter Cc: Yisheng Xie Link: http://lore.kernel.org/lkml/20200213064306.160480-3-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Support --prefix/--prefix-strip

2020-01-14T15:02:19+00:00

The objdump utility has useful --prefix / --prefix-strip options to allow changing source code file names hardcoded into executables' debug info. Add options to 'perf report', 'perf top' and 'perf annotate', which are then passed to objdump. $ mkdir foo $ echo 'main() { for (;;); }' > foo/foo.c $ gcc -g foo/foo.c foo/foo.c:1:1: warning: return type defaults to ‘int’ [-Wimplicit-int] 1 | main() { for (;;); } | ^~~~ $ perf record ./a.out ^C[ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.230 MB perf.data (5721 samples) ] $ mv foo bar $ perf annotate $ perf annotate --prefix=/home/ak/lsrc/git/bar --prefix-strip=5 Signed-off-by: Andi Kleen Tested-by: Jiri Olsa LPU-Reference: 20200107210444.214071-1-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Pass a 'map_symbol' in places receiving a pair of 'map' and 'symbol' pointers

2019-11-12T11:20:53+00:00

We are already passing things like: symbol__annotate(ms->sym, ms->map, ...) So shorten the signature of such functions to receive the 'map_symbol' pointer. This also paves the way to having the 'struct map_groups' pointer in the 'struct map_symbol' so that we can get rid of 'struct map'->groups. Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-23yx8v1t41nzpkpi7rdrozww@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf diff: Report noisy for cycles diff

2019-10-11T13:57:00+00:00

This patch prints the stddev and hist for the cycles diff of program block. It can help us to understand if the cycles is noisy or not. This patch is inspired by Andi Kleen's patch: https://lwn.net/Articles/600471/ We create new option '--cycles-hist'. Example: perf record -b ./div perf record -b ./div perf diff -c cycles # Baseline [Program Block Range] Cycles Diff Shared Object Symbol # ........ .......................................................... .... ................. ............................ # 46.72% [div.c:40 -> div.c:40] 0 div [.] main 46.72% [div.c:42 -> div.c:44] 0 div [.] main 46.72% [div.c:42 -> div.c:39] 0 div [.] main 20.54% [random_r.c:357 -> random_r.c:394] 1 libc-2.27.so [.] __random_r 20.54% [random_r.c:357 -> random_r.c:380] 0 libc-2.27.so [.] __random_r 20.54% [random_r.c:388 -> random_r.c:388] 0 libc-2.27.so [.] __random_r 20.54% [random_r.c:388 -> random_r.c:391] 0 libc-2.27.so [.] __random_r 17.04% [random.c:288 -> random.c:291] 0 libc-2.27.so [.] __random 17.04% [random.c:291 -> random.c:291] 0 libc-2.27.so [.] __random 17.04% [random.c:293 -> random.c:293] 0 libc-2.27.so [.] __random 17.04% [random.c:295 -> random.c:295] 0 libc-2.27.so [.] __random 17.04% [random.c:295 -> random.c:295] 0 libc-2.27.so [.] __random 17.04% [random.c:298 -> random.c:298] 0 libc-2.27.so [.] __random 8.40% [div.c:22 -> div.c:25] 0 div [.] compute_flag 8.40% [div.c:27 -> div.c:28] 0 div [.] compute_flag 5.14% [rand.c:26 -> rand.c:27] 0 libc-2.27.so [.] rand 5.14% [rand.c:28 -> rand.c:28] 0 libc-2.27.so [.] rand 2.15% [rand@plt+0 -> rand@plt+0] 0 div [.] rand@plt 0.00% [kernel.kallsyms] [k] __x86_indirect_thunk_rax 0.00% [do_mmap+714 -> do_mmap+732] -10 [kernel.kallsyms] [k] do_mmap 0.00% [do_mmap+737 -> do_mmap+765] 1 [kernel.kallsyms] [k] do_mmap 0.00% [do_mmap+262 -> do_mmap+299] 0 [kernel.kallsyms] [k] do_mmap 0.00% [__x86_indirect_thunk_r15+0 -> __x86_indirect_thunk_r15+0] 7 [kernel.kallsyms] [k] __x86_indirect_thunk_r15 0.00% [native_sched_clock+0 -> native_sched_clock+119] -1 [kernel.kallsyms] [k] native_sched_clock 0.00% [native_write_msr+0 -> native_write_msr+16] -13 [kernel.kallsyms] [k] native_write_msr When we enable the option '--cycles-hist', the output is perf diff -c cycles --cycles-hist # Baseline [Program Block Range] Cycles Diff stddev/Hist Shared Object Symbol # ........ .......................................................... .... ................. ................. ............................ # 46.72% [div.c:40 -> div.c:40] 0 ± 37.8% ▁█▁▁██▁█ div [.] main 46.72% [div.c:42 -> div.c:44] 0 ± 49.4% ▁▁▂█▂▂▂▂ div [.] main 46.72% [div.c:42 -> div.c:39] 0 ± 24.1% ▃█▂▄▁▃▂▁ div [.] main 20.54% [random_r.c:357 -> random_r.c:394] 1 ± 33.5% ▅▂▁█▃▁▂▁ libc-2.27.so [.] __random_r 20.54% [random_r.c:357 -> random_r.c:380] 0 ± 39.4% ▁▁█▁██▅▁ libc-2.27.so [.] __random_r 20.54% [random_r.c:388 -> random_r.c:388] 0 libc-2.27.so [.] __random_r 20.54% [random_r.c:388 -> random_r.c:391] 0 ± 41.2% ▁▃▁▂█▄▃▁ libc-2.27.so [.] __random_r 17.04% [random.c:288 -> random.c:291] 0 ± 48.8% ▁▁▁▁███▁ libc-2.27.so [.] __random 17.04% [random.c:291 -> random.c:291] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random 17.04% [random.c:293 -> random.c:293] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random 17.04% [random.c:295 -> random.c:295] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random 17.04% [random.c:295 -> random.c:295] 0 libc-2.27.so [.] __random 17.04% [random.c:298 -> random.c:298] 0 ± 75.6% ▃█▁▁▁▁▁▁ libc-2.27.so [.] __random 8.40% [div.c:22 -> div.c:25] 0 ± 42.1% ▁▃▁▁███▁ div [.] compute_flag 8.40% [div.c:27 -> div.c:28] 0 ± 41.8% ██▁▁▄▁▁▄ div [.] compute_flag 5.14% [rand.c:26 -> rand.c:27] 0 ± 37.8% ▁▁▁████▁ libc-2.27.so [.] rand 5.14% [rand.c:28 -> rand.c:28] 0 libc-2.27.so [.] rand 2.15% [rand@plt+0 -> rand@plt+0] 0 div [.] rand@plt 0.00% [kernel.kallsyms] [k] __x86_indirect_thunk_rax 0.00% [do_mmap+714 -> do_mmap+732] -10 [kernel.kallsyms] [k] do_mmap 0.00% [do_mmap+737 -> do_mmap+765] 1 [kernel.kallsyms] [k] do_mmap 0.00% [do_mmap+262 -> do_mmap+299] 0 [kernel.kallsyms] [k] do_mmap 0.00% [__x86_indirect_thunk_r15+0 -> __x86_indirect_thunk_r15+0] 7 [kernel.kallsyms] [k] __x86_indirect_thunk_r15 0.00% [native_sched_clock+0 -> native_sched_clock+119] -1 ± 38.5% ▄█▁ [kernel.kallsyms] [k] native_sched_clock 0.00% [native_write_msr+0 -> native_write_msr+16] -13 ± 47.1% ▁█▇▃▁▁ [kernel.kallsyms] [k] native_write_msr v8: --- Rebase to perf/core branch v7: --- 1. v6 got Jiri's ACK. 2. Rebase to latest perf/core branch. v6: --- 1. Jiri provides better code for using data__hpp_register() in ui_init(). Use this code in v6. v5: --- 1. Refine the use of data__hpp_register() in ui_init() according to Jiri's suggestion. v4: --- 1. Rename the new option from '--noisy' to '--cycles-hist' 2. Remove the option '-n'. 3. Only update the spark value and stats when '--cycles-hist' is enabled. 4. Remove the code of printing '..'. v3: --- 1. Move the histogram to a separate column 2. Move the svals[] out of struct stats v2: --- Jiri got a compile error, CC builtin-diff.o builtin-diff.c: In function ‘compute_cycles_diff’: builtin-diff.c:712:10: error: taking the absolute value of unsigned type ‘u64’ {aka ‘long unsigned int’} has no effect [-Werror=absolute-value] 712 | labs(pair->block_info->cycles_spark[i] - | ^~~~ Because the result of u64 - u64 is still u64. Now we change the type of cycles_spark[] to s64. Signed-off-by: Jin Yao Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: Kan Liang Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20190925011446.30678-1-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo