kernel/linux.git/tools/perf/Documentation, branch v6.19.11

perf timechart: Add record support for output perf.data path

2025-12-03T19:07:23+00:00

The '-o' option exists for the SVG creation but not for `perf timechart record`. Add to better allow testing. Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tools: Merge deferred user callchains

2025-12-03T05:59:14+00:00

Save samples with deferred callchains in a separate list and deliver them after merging the user callchains. If users don't want to merge they can set tool->merge_deferred_callchains to false to prevent the behavior. With previous result, now perf script will show the merged callchains. $ perf script ... pwd 2312 121.163435: 249113 cpu/cycles/P: ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms]) ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms]) ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms]) ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms]) ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms]) ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms]) ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms]) 7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) ... The old output can be get using --no-merge-callchain option. Also perf report can get the user callchain entry at the end. $ perf report --no-children --stdio -q -S __build_id_parse.isra.0 # symbol: __build_id_parse.isra.0 8.40% pwd [kernel.kallsyms] | ---__build_id_parse.isra.0 perf_event_mmap mprotect_fixup do_mprotect_pkey __x64_sys_mprotect do_syscall_64 entry_SYSCALL_64_after_hwframe mprotect _dl_sysdep_start _dl_start_user Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf record: Add --call-graph fp,defer option for deferred callchains

2025-12-03T05:59:13+00:00

Add a new callchain record mode option for deferred callchains. For now it only works with FP (frame-pointer) mode. And add the missing feature detection logic to clear the flag on old kernels. $ perf record --call-graph fp,defer -vv true ... ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|CALLCHAIN|PERIOD read_format ID|LOST disabled 1 inherit 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 sample_id_all 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 defer_callchain 1 defer_output 1 ------------------------------------------------------------ sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -22 switching off deferred callchain support Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf docs: arm-spe: Document new SPE filtering features

2025-11-24T20:20:07+00:00

FEAT_SPE_EFT and FEAT_SPE_FDS etc have new user facing format attributes so document them. Also document existing 'event_filter' bits that were missing from the doc and the fact that latency values are stored in the weight field. Reviewed-by: Leo Yan Tested-by: Leo Yan Reviewed-by: Ian Rogers Signed-off-by: James Clark Acked-by: Peter Zijlstra (Intel) Signed-off-by: Namhyung Kim

perf build: Remove NO_AUXTRACE build option

2025-11-14T07:03:11+00:00

The NO_AUXTRACE build option was used when the __get_cpuid feature test failed or if it was provided on the command line. The option no longer avoids a dependency on a library and so having the option is just adding complexity to the code base. Remove the option CONFIG_AUXTRACE from Build files and HAVE_AUXTRACE_SUPPORT by assuming it is always defined. Signed-off-by: Ian Rogers Reviewed-by: James Clark Signed-off-by: Namhyung Kim

perf c2c: Add annotation support to perf c2c report

2025-10-19T03:49:59+00:00

Perf c2c report currently specified the code address and source:line information in the cacheline browser, while it is lack of annotation support like perf report to directly show the disassembly code for the particular symbol shared that same cacheline. This patches add a key 'a' binding to the cacheline browser which reuse the annotation browser to show the disassembly view for easier analysis of cacheline contentions. Signed-off-by: Tianyou Li Reviewed-by: Dapeng Mi Reviewed-by: Thomas Falcon Reviewed-by: Jiebin Sun Reviewed-by: Pan Deng Reviewed-by: Zhiguo Zhou Reviewed-by: Wangyang Guo Tested-by: Ravi Bangoria Signed-off-by: Namhyung Kim

perf docs: Document building with Clang

2025-10-06T19:49:25+00:00

Add example commands for building perf with Clang. Since recent Android NDK releases use Clang as the default compiler, a separate Android specific document is no longer needed; point to the general build documentation instead. Signed-off-by: Leo Yan Reviewed-by: Ian Rogers Link: https://lore.kernel.org/r/20251006-perf_build_android_ndk-v3-9-4305590795b2@arm.com Cc: Palmer Dabbelt Cc: Albert Ou Cc: Alexandre Ghiti Cc: Nick Desaulniers Cc: Justin Stitt Cc: Bill Wendling Cc: Adrian Hunter Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: Nathan Chancellor Cc: James Clark Cc: linux-riscv@lists.infradead.org Cc: llvm@lists.linux.dev Cc: Paul Walmsley Cc: linux-kernel@vger.kernel.org Cc: linux-perf-users@vger.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf check: Add libLLVM feature

2025-10-06T18:24:13+00:00

Advertise when perf is built with the HAVE_LIBLLVM_SUPPORT option. Committer testing: $ perf -vv | grep LLVM libLLVM: [ on ] # HAVE_LIBLLVM_SUPPORT $ And the form to use in scripts, notably the tools/perf/tests/shell/ 'perf test' ones: $ perf check feature libllvm libLLVM: [ on ] # HAVE_LIBLLVM_SUPPORT $ perf check -q feature libllvm && echo LLVM is present LLVM is present $ perf check -q feature liballvm && echo ALLVM is present $ Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Andi Kleen Cc: Athira Rajeev Cc: Bill Wendling Cc: Charlie Jenkins Cc: Collin Funk Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Eric Biggers Cc: Haibo Xu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Justin Stitt Cc: Li Huafei Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Song Liu Cc: Stephen Brennan Signed-off-by: Arnaldo Carvalho de Melo

perf record: Add ratio-to-prev term

2025-10-03T19:49:51+00:00

Provide ratio-to-prev term which allows the user to set the event sample period of two events corresponding to a desired ratio. If using on an Intel x86 platform with Auto Counter Reload support, also set corresponding event's config2 attribute with a bitmask which counters to reset and which counters to sample if the desired ratio is met or exceeded. On other platforms, only the sample period is affected by the ratio-to-prev term. Reviewed-by: Ian Rogers Signed-off-by: Thomas Falcon Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Dapeng Mi Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix duplicated words in documentation and comments

2025-10-01T12:44:02+00:00

- "the the" - "in in" - "a a" Reviewed-by: Ian Rogers Signed-off-by: Markus Heidelberg Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo