kernel/linux.git/tools/perf/util/annotate.c, branch v6.13.2

perf annotate: Use an array for the disassembler preference

2025-02-08T09:02:13+00:00

[ Upstream commit bde4ccfd5ab5361490514fc4af7497989cfbee17 ] Prior to this change a string was used which could cause issues with an unrecognized disassembler in symbol__disassembler. Change to initializing an array of perf_disassembler enum values. If a value already exists then adding it a second time is ignored to avoid array out of bounds problems present in the previous code, it also allows a statically sized array and removes memory allocation needs. Errors in the disassembler string are reported when the config is parsed during perf annotate or perf top start up. If the array is uninitialized after processing the config file the default llvm, capstone then objdump values are added but without a need to parse a string. Fixes: a6e8a58de629 ("perf disasm: Allow configuring what disassemblers to use") Closes: https://lore.kernel.org/lkml/CAP-5=fUdfCyxmEiTpzS2uumUp3-SyQOseX2xZo81-dQtWXj6vA@mail.gmail.com/ Signed-off-by: Ian Rogers Tested-by: Namhyung Kim Link: https://lore.kernel.org/r/20250124043856.1177264-1-irogers@google.com Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf disasm: Allow configuring what disassemblers to use

2024-11-13T19:27:35+00:00

The perf tools annotation code used for a long time parsing the output of binutils's objdump (or its reimplementations, like llvm's) to then parse and augment it with samples, allow navigation, etc. More recently disassemblers from the capstone and llvm (libraries, not parsing the output of tools using those libraries to mimic binutils's objdump output) were introduced. So when all those methods are available, there is a static preference for a series of attempts of disassembling a binary, with the 'llvm, capstone, objdump' sequence being hard coded. This patch allows users to change that sequence, specifying via a 'perf config' 'annotate.disassemblers' entry which and in what order disassemblers should be attempted. As alluded to in the comments in the source code of this series, this flexibility is useful for users and developers alike, elliminating the requirement to rebuild the tool with some specific set of libraries to see how the output of disassembling would be for one of these methods. root@x1:~# rm -f ~/.perfconfig root@x1:~# perf annotate -v --stdio2 update_load_avg symbol__disassemble: filename=/usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux, sym=update_load_avg, start=0xffffffffb6148fe0, en> annotating [0x6ff7170] /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux : [0x7407ca0] update_load_avg Disassembled with llvm annotate.disassemblers=llvm,capstone,objdump Samples: 66 of event 'cpu_atom/cycles/P', 10000 Hz, Event count (approx.): 5185444, [percent: local period] update_load_avg() /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux Percent 0xffffffff81148fe0 : 1.61 pushq %r15 pushq %r14 1.00 pushq %r13 movl %edx,%r13d 1.90 pushq %r12 pushq %rbp movq %rsi,%rbp pushq %rbx movq %rdi,%rbx subq $0x18,%rsp 15.14 movl 0x1a4(%rdi),%eax root@x1:~# perf config annotate.disassemblers=capstone root@x1:~# cat ~/.perfconfig # this file is auto-generated. [annotate] disassemblers = capstone root@x1:~# root@x1:~# perf annotate -v --stdio2 update_load_avg Disassembled with capstone annotate.disassemblers=capstone Samples: 66 of event 'cpu_atom/cycles/P', 10000 Hz, Event count (approx.): 5185444, [percent: local period] update_load_avg() /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux Percent 0xffffffff81148fe0 : 1.61 pushq %r15 pushq %r14 1.00 pushq %r13 movl %edx,%r13d 1.90 pushq %r12 pushq %rbp movq %rsi,%rbp pushq %rbx movq %rdi,%rbx subq $0x18,%rsp 15.14 movl 0x1a4(%rdi),%eax root@x1:~# perf config annotate.disassemblers=objdump,capstone root@x1:~# perf config annotate.disassemblers annotate.disassemblers=objdump,capstone root@x1:~# cat ~/.perfconfig # this file is auto-generated. [annotate] disassemblers = objdump,capstone root@x1:~# perf annotate -v --stdio2 update_load_avg Executing: objdump --start-address=0xffffffff81148fe0 \ --stop-address=0xffffffff811497aa \ -d --no-show-raw-insn -S -C "$1" Disassembled with objdump annotate.disassemblers=objdump,capstone Samples: 66 of event 'cpu_atom/cycles/P', 10000 Hz, Event count (approx.): 5185444, [percent: local period] update_load_avg() /usr/lib/debug/lib/modules/6.11.4-201.fc40.x86_64/vmlinux Percent Disassembly of section .text: ffffffff81148fe0 : #define DO_ATTACH 0x4 ffffffff81148fe0 : #define DO_ATTACH 0x4 #define DO_DETACH 0x8 /* Update task and its cfs_rq load average */ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { 1.61 push %r15 push %r14 1.00 push %r13 mov %edx,%r13d 1.90 push %r12 push %rbp mov %rsi,%rbp push %rbx mov %rdi,%rbx sub $0x18,%rsp } /* rq->task_clock normalized against any time this cfs_rq has spent throttled */ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { if (unlikely(cfs_rq->throttle_count)) 15.14 mov 0x1a4(%rdi),%eax root@x1:~# After adding a way to select the disassembler from the command line a 'perf test' comparing the output of the various diassemblers should be introduced, to test these codebases. Acked-by: Ian Rogers Cc: Adrian Hunter Cc: Athira Rajeev Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Steinar H. Gunderson Link: https://lore.kernel.org/r/20241111151734.1018476-4-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf dwarf-regs: Pass accurate disassembly machine to get_dwarf_regnum

2024-11-09T16:39:13+00:00

Rather than pass 0/EM_NONE, use the value computed in the disasm struct arch. Switch the EM_NONE case to EM_HOST, rewriting EM_NONE if it were passed to get_dwarf_regnum. Pass a flags value as architectures like csky need the flags to determine the ABI variant. Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Ian Rogers Cc: Anup Patel Cc: Yang Jihong Cc: Palmer Dabbelt Cc: David S. Miller Cc: Albert Ou Cc: Shenlin Liang Cc: Nick Terrell Cc: Guilherme Amadio Cc: Steinar H. Gunderson Cc: Changbin Du Cc: Alexander Lobakin Cc: Przemek Kitszel Cc: Huacai Chen Cc: Guo Ren Cc: Masahiro Yamada Cc: Will Deacon Cc: James Clark Cc: Mike Leach Cc: Chen Pei Cc: Leo Yan Cc: Oliver Upton Cc: Aditya Gupta Cc: Kajol Jain Cc: Athira Rajeev Cc: linux-arm-kernel@lists.infradead.org Cc: linux-riscv@lists.infradead.org Cc: Bibo Mao Cc: John Garry Cc: Atish Patra Cc: Dima Kogan Cc: Paul Walmsley Cc: Dr. David Alan Gilbert Cc: linux-csky@vger.kernel.org Link: https://lore.kernel.org/r/20241108234606.429459-6-irogers@google.com Signed-off-by: Namhyung Kim

perf env: Find correct branch counter info on hybrid

2024-09-11T16:08:46+00:00

No event is printed in the "Branch Counter" column on hybrid machines. For example, $ perf record -e "{cpu_core/branch-instructions/pp,cpu_core/branches/}:S" -j any,counter $ perf report --total-cycles # Branch counter abbr list: # cpu_core/branch-instructions/pp = A # cpu_core/branches/ = B # '-' No event occurs # '+' Event occurrences may be lost due to branch counter saturated # # Sampled Cycles% Sampled Cycles Avg Cycles% Avg Cycles Branch Counter # ............... .............. ........... .......... .............. 44.54% 727.1K 0.00% 1 |+ |+ | 36.31% 592.7K 0.00% 2 |+ |+ | 17.83% 291.1K 0.00% 1 |+ |+ | The branch counter information (br_cntr_width and br_cntr_nr) in the perf_env is retrieved from the CPU_PMU_CAPS. However, the CPU_PMU_CAPS is not available on hybrid machines. Without the width information, the number of occurrences of an event cannot be calculated. For a hybrid machine, the caps information should be retrieved from the PMU_CAPS, and stored in the perf_env->pmu_caps. Add a perf_env__find_br_cntr_info() to return the correct branch counter information from the corresponding fields. Committer notes: While testing I couldn't s ee those "Branch counter" columns enabled by pressing 'B' on the TUI, after reporting it to the list Kan explained the situation: For a hybrid client, the "Branch Counter" feature is only supported starting from the just released Lunar Lake. Perf falls back to only "ANY" on your Raptor Lake. The "The branch counter is not available" message is expected. Here is the 'perf evlist' result from my Lunar Lake machine, # perf evlist -v cpu_core/branch-instructions/pp: type: 4 (cpu_core), size: 136, config: 0xc4 (branch-instructions), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|READ|PERIOD|BRANCH_STACK|IDENTIFIER, read_format: ID|GROUP|LOST, disabled: 1, freq: 1, enable_on_exec: 1, precise_ip: 2, sample_id_all: 1, exclude_guest: 1, branch_sample_type: ANY|COUNTERS # Fixes: 6f9d8d1de2c61288 ("perf script: Add branch counters") Reviewed-by: Ian Rogers Signed-off-by: Kan Liang Cc: Adrian Hunter Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Link: https://lore.kernel.org/r/20240909184201.553519-1-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Treat 'call' instruction as stack operation

2024-09-10T20:32:47+00:00

I found some portion of mem-store events sampled on CALL instruction which has no memory access. But it actually saves a return address into stack. It should be considered as a stack operation like RET instruction. Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240909214251.3033827-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Display the branch counter histogram

2024-08-14T13:20:40+00:00

Display the branch counter histogram in the annotation view. Press 'B' to display the branch counter's abbreviation list as well. Samples: 1M of events 'anon group { branch-instructions:ppp, branch-misses }', 4000 Hz, Event count (approx.): f3 /home/sdp/test/tchain_edit [Percent: local period] Percent │ IPC Cycle Branch Counter (Average IPC: 1.39, IPC Coverage: 29.4%) │ 0000000000401755 : 0.00 0.00 │ endbr64 │ push %rbp │ mov %rsp,%rbp │ movl $0x0,-0x4(%rbp) 0.00 0.00 │1.33 3 |A |- | ↓ jmp 25 11.03 11.03 │ 11: mov -0x4(%rbp),%eax │ and $0x1,%eax │ test %eax,%eax 17.13 17.13 │2.41 1 |A |- | ↓ je 21 │ addl $0x1,-0x4(%rbp) 21.84 21.84 │2.22 2 |AA |- | ↓ jmp 25 17.13 17.13 │ 21: addl $0x1,-0x4(%rbp) 21.84 21.84 │ 25: cmpl $0x270f,-0x4(%rbp) 11.03 11.03 │0.61 3 |A |- | ↑ jle 11 │ nop │ pop %rbp 0.00 0.00 │0.24 20 |AA |B | ← ret Originally-by: Tinghao Zhang Reviewed-by: Andi Kleen Signed-off-by: Kan Liang Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Stephane Eranian Link: https://lore.kernel.org/r/20240813160208.2493643-8-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf report: Display the branch counter histogram

2024-08-14T13:20:40+00:00

Reusing the existing --total-cycles option to display the branch counters. Add a new PERF_HPP_REPORT__BLOCK_BRANCH_COUNTER to display the logged branch counter events. They are shown right after all the cycle-related annotations. Extend the 'struct block_info' to store and pass the branch counter related information. The annotation_br_cntr_entry() is to print the histogram of each branch counter event. If the number of logged events is less than 4, the exact number of the abbr name is printed. Otherwise, using '+' to stands for more than 3 events. Assume the number of logged events is less than 4. The annotation_br_cntr_abbr_list() prints the branch counter's abbreviation list. Press 'B' to display the list in the TUI mode. $ perf record -e "{branch-instructions:ppp,branch-misses}:S" -j any,counter $ perf report --total-cycles --stdio # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 1M of events 'anon group { branch-instructions:ppp, branch-misses }' # Event count (approx.): 1610046 # # Branch counter abbr list: # branch-instructions:ppp = A # branch-misses = B # '-' No event occurs # '+' Event occurrences may be lost due to branch counter saturated # # Sampled Cycles% Sampled Cycles Avg Cycles% Avg Cycles Branch Counter [Program Block Range] # ............... .............. ........... .......... .............. .................. # 57.55% 2.5M 0.00% 3 |A |- | ... 25.27% 1.1M 0.00% 2 |AA |- | ... 15.61% 667.2K 0.00% 1 |A |- | ... 0.16% 6.9K 0.81% 575 |A |- | ... 0.16% 6.8K 1.38% 977 |AA |- | ... 0.16% 6.8K 0.04% 28 |AA |B | ... 0.15% 6.6K 1.33% 946 |A |- | ... 0.11% 4.5K 0.06% 46 |AAA+|- | ... 0.10% 4.4K 0.88% 624 |A |- | ... 0.09% 3.7K 0.74% 524 |AAA+|B | ... With -v applied, # Sampled Cycles% Sampled Cycles Avg Cycles% Avg Cycles Branch Counter [Program Block Range] # ............... .............. ........... .......... .............. .................. # 57.55% 2.5M 0.00% 3 A=1 ,B=- ... 25.27% 1.1M 0.00% 2 A=2 ,B=- ... 15.61% 667.2K 0.00% 1 A=1 ,B=- ... 0.16% 6.9K 0.81% 575 A=1 ,B=- ... 0.16% 6.8K 1.38% 977 A=2 ,B=- ... 0.16% 6.8K 0.04% 28 A=2 ,B=1 ... 0.15% 6.6K 1.33% 946 A=1 ,B=- ... 0.11% 4.5K 0.06% 46 A=3+,B=- ... 0.10% 4.4K 0.88% 624 A=1 ,B=- ... 0.09% 3.7K 0.74% 524 A=3+,B=1 ... Reviewed-by: Andi Kleen Signed-off-by: Kan Liang Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Stephane Eranian Link: https://lore.kernel.org/r/20240813160208.2493643-7-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Save branch counters for each block

2024-08-14T13:20:40+00:00

When annotating a basic block, it's useful to display the occurrences of other events in the block. The branch counter feature is only available for newer Intel platforms. So a dedicated option to display the branch counters is not introduced. Reuse the existing --total-cycles option, which triggers the annotation of a basic block and displays the cycle-related annotation. When the branch counters information is available, the branch counters are automatically appended after all the cycle-related annotation. Accounting the branch counters as well when accounting the cycles in hist__account_cycles(). In 'struct annotated_branch', introduce a br_cntr array to save the accumulation of each branch counter. In a sample, all the branch counters for a branch are saved in a u64 space. Because the saturation of a branch counter is small, e.g., for Intel Sierra Forest, the saturation is only 3. Add ANNOTATION__BR_CNTR_SATURATED_FLAG to indicate if a branch counter once saturated. That can be used to indicate a potential event lost because of the saturation. Reviewed-by: Andi Kleen Signed-off-by: Kan Liang Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Stephane Eranian Link: https://lore.kernel.org/r/20240813160208.2493643-5-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Cache debuginfo for data type profiling

2024-08-08T12:34:43+00:00

In find_data_type(), it creates and deletes a debug info whenver it tries to find data type for a sample. This is inefficient and it most likely accesses the same binary again and again. Let's add a single entry cache the debug info structure for the last DSO. Depending on sample data, it usually gives me 2~3x (and sometimes more) speed ups. Note that this will introduce a little difference in the output due to the order of checking stack operations. It used to check the stack ops before checking the availability of debug info but I moved it after the symbol check. So it'll report stack operations in DSOs without debug info as unknown. But I think it's ok and better to have the checking near the caching logic. Committer testing: root@x1:~# perf mem record -a sleep 5s root@x1:~# perf evlist cpu_atom/mem-loads,ldlat=30/P cpu_atom/mem-stores/P dummy:u root@x1:~# diff -u before after --- before 2024-08-08 09:33:53.880780784 -0300 +++ after 2024-08-08 09:35:13.917325041 -0300 @@ -81,8 +81,8 @@ # Overhead Data Type # ........ ......... # - 55.43% (unknown) - 11.61% (stack operation) + 55.56% (unknown) + 11.48% (stack operation) 4.93% struct pcpu_hot 3.26% unsigned int 2.48% struct Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Athira Rajeev Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240805234648.1453689-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add --skip-empty option

2024-08-05T19:14:01+00:00

Like in 'perf report', we want to hide empty events in the 'perf annotate' output. This is consistent when the option is set in perf report. For example, the following command would use 3 events including dummy. $ perf mem record -a -- perf test -w noploop $ perf evlist cpu/mem-loads,ldlat=30/P cpu/mem-stores/P dummy:u Just using perf annotate with --group will show the all 3 events. $ perf annotate --group --stdio | head Percent | Source code & Disassembly of ... -------------------------------------------------------------- : 0 0xe060 <_dl_relocate_object>: 0.00 0.00 0.00 : e060: pushq %rbp 0.00 0.00 0.00 : e061: movq %rsp, %rbp 0.00 0.00 0.00 : e064: pushq %r15 0.00 0.00 0.00 : e066: movq %rdi, %r15 0.00 0.00 0.00 : e069: pushq %r14 0.00 0.00 0.00 : e06b: pushq %r13 0.00 0.00 0.00 : e06d: movl %edx, %r13d Now with --skip-empty, it'll hide the last dummy event. $ perf annotate --group --stdio --skip-empty | head Percent | Source code & Disassembly of ... ------------------------------------------------------ : 0 0xe060 <_dl_relocate_object>: 0.00 0.00 : e060: pushq %rbp 0.00 0.00 : e061: movq %rsp, %rbp 0.00 0.00 : e064: pushq %r15 0.00 0.00 : e066: movq %rdi, %r15 0.00 0.00 : e069: pushq %r14 0.00 0.00 : e06b: pushq %r13 0.00 0.00 : e06d: movl %edx, %r13d Committer testing: root@x1:~# perf evlist cpu_atom/mem-loads,ldlat=30/P cpu_atom/mem-stores/P dummy:u root@x1:~# Before: root@x1:~# perf annotate --group --stdio2 do_lookup_x | head -25 Samples: 20 of events 'cpu_atom/mem-loads,ldlat=30/P, cpu_atom/mem-stores/P, dummy:u', 4000 Hz, Event count (approx.): 769079, [percent: local period] do_lookup_x() /usr/lib64/ld-linux-x86-64.so.2 Percent 0x9900 : pushq %rbp movq %rsp,%rbp pushq %r15 pushq %r14 pushq %r13 pushq %r12 pushq %rbx subq $0x88,%rsp movq %rdi,-0x50(%rbp) movl 8(%r9),%edi movq 0x10(%rbp),%r12 movq 0x28(%rbp),%r10 movq %rdx,-0x70(%rbp) movq %rcx,-0x58(%rbp) movq %rdi,%r11 0.00 5.73 0.00 movq %r8,-0x68(%rbp) movq (%r9),%r8 movl %esi,%eax 8.30 0.00 0.00 movl 0x30(%rbp),%r9d movl %esi,%r15d shrl $6, %eax movq %r8,%r13 root@x1:~# After: root@x1:~# perf annotate --group --skip-empty --stdio2 do_lookup_x | head -25 Samples: 20 of events 'cpu_atom/mem-loads,ldlat=30/P, cpu_atom/mem-stores/P', 4000 Hz, Event count (approx.): 769079, [percent: local period] do_lookup_x() /usr/lib64/ld-linux-x86-64.so.2 Percent 0x9900 : pushq %rbp movq %rsp,%rbp pushq %r15 pushq %r14 pushq %r13 pushq %r12 pushq %rbx subq $0x88,%rsp movq %rdi,-0x50(%rbp) movl 8(%r9),%edi movq 0x10(%rbp),%r12 movq 0x28(%rbp),%r10 movq %rdx,-0x70(%rbp) movq %rcx,-0x58(%rbp) movq %rdi,%r11 0.00 5.73 movq %r8,-0x68(%rbp) movq (%r9),%r8 movl %esi,%eax 8.30 0.00 movl 0x30(%rbp),%r9d movl %esi,%r15d shrl $6, %eax movq %r8,%r13 root@x1:~# Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240803211332.1107222-6-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo