kernel/linux.git/tools/perf/util/thread.h, branch v7.2-rc1

perf env, dso, thread: Add _endian variants for e_machine helpers

2026-06-03T19:45:21+00:00

Add perf_arch_is_big_endian(), dso__read_e_machine_endian(), dso__e_machine_endian(), and thread__e_machine_endian() to support bi-endianness and cross-architecture analysis without breaking the existing API. These helpers allow querying the absolute endianness of a DSO or thread, which is required for tools like Capstone that need to set the correct disassembly mode. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Alexander Gordeev Cc: Heiko Carstens Cc: Honglei Wang Cc: Jan Polensky Cc: Sumanth Korikkar Cc: Thomas Richter Cc: Vasily Gorbik Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Add optional e_flags output argument to thread__e_machine

2026-01-26T21:21:20+00:00

The e_flags are needed to accurately compute complete perf register information for CSKY. Add the ability to read and have this value associated with a thread. This change doesn't wire up the use of the e_flags except in disasm where use already exists but just wasn't set up yet. Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Chun-Tse Shao Cc: Guo Ren Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Stephen Brennan Cc: Swapnil Sapkal Cc: Tianyou Li Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Ensure comm_lock held for comm_list

2025-06-11T20:40:31+00:00

perf callchain: Always populate the addr_location map when adding IP

2025-05-31T11:58:30+00:00

Dropping symbols also meant the callchain maps wasn't populated, but the callchain map is needed to find the DSO. Plumb the symbols option better, falling back to thread__find_map() rather than thread__find_symbol() when symbols are disabled. Fixes: 02b2705017d2e5ad ("perf callchain: Allow symbols to be optional when resolving a callchain") Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Athira Rajeev Cc: Ben Gainey Cc: Chaitanya S Prakash Cc: Charlie Jenkins Cc: Chun-Tse Shao Cc: Colin Ian King Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Graham Woodward Cc: Howard Chu Cc: Ilkka Koskinen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Kajol Jain Cc: Kan Liang Cc: Krzysztof Łopatowski Cc: Leo Yan Cc: Levi Yun Cc: Li Huafei Cc: linux-arm-kernel@lists.infradead.org Cc: Mark Rutland Cc: Martin Liška Cc: Masami Hiramatsu Cc: Matt Fleming Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Song Liu Cc: Steinar H. Gunderson Cc: Stephen Brennan Cc: Steve Clevenger Cc: Thomas Falcon Cc: Veronika Molnarova Cc: Weilin Wang Cc: Will Deacon Cc: Yicong Yang Cc: Yujie Liu Cc: Zhongqiu Han Cc: Zixian Cai Link: https://lore.kernel.org/r/20250529044000.759937-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

Revert "perf thread: Ensure comm_lock held for comm_list"

2025-05-28T15:59:17+00:00

This reverts commit 8f454c95817d15ee529d58389612ea4b34f5ffb3. 'perf top' is freezing on exit sometimes, bisected to this one, revert. Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Bill Wendling Cc: Chaitanya S Prakash Cc: Fei Lang Cc: Howard Chu Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Justin Stitt Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Stephen Brennan Link: https://lore.kernel.org/r/aDcyvvOKZkRYbjul@x1 Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Ensure comm_lock held for comm_list

2025-05-21T18:07:13+00:00

Add thread safety annotations for comm_list and add locking for two instances where the list is accessed without the lock held (in contradiction to ____thread__set_comm()). Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Bill Wendling Cc: Chaitanya S Prakash Cc: Fei Lang Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Justin Stitt Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Stephen Brennan Link: https://lore.kernel.org/r/20250519224645.1810891-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Add support for reading the e_machine type for a thread

2025-03-21T05:58:05+00:00

First try to read the e_machine from the dsos associated with the thread's maps. If live use the executable from /proc/pid/exe and read the e_machine from the ELF header. On failure use EM_HOST. Change builtin-trace syscall functions to pass e_machine from the thread rather than EM_HOST, so that in later patches when syscalltbl can use the e_machine the system calls are specific to the architecture. Signed-off-by: Ian Rogers Reviewed-by: Namhyung Kim Acked-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/r/20250319050741.269828-8-irogers@google.com Signed-off-by: Namhyung Kim

perf callchain: Fix stitch LBR memory leaks

2024-08-08T20:30:27+00:00

The 'struct callchain_cursor_node' has a 'struct map_symbol' whose maps and map members are reference counted. Ensure these values use a _get routine to increment the reference counts and use map_symbol__exit() to release the reference counts. Do similar for 'struct thread's prev_lbr_cursor, but save the size of the prev_lbr_cursor array so that it may be iterated. Ensure that when stitch_nodes are placed on the free list the map_symbols are exited. Fix resolve_lbr_callchain_sample() by replacing list_replace_init() to list_splice_init(), so the whole list is moved and nodes aren't leaked. A reproduction of the memory leaks is possible with a leak sanitizer build in the perf report command of: ``` $ perf record -e cycles --call-graph lbr perf test -w thloop $ perf report --stitch-lbr ``` Reviewed-by: Kan Liang Fixes: ff165628d72644e3 ("perf callchain: Stitch LBR call stack") Signed-off-by: Ian Rogers [ Basic tests after applying the patch, repeating the example above ] Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Anne Macedo Cc: Changbin Du Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240808054644.1286065-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Move machine's threads into its own abstraction

2024-03-04T06:51:44+00:00

Move thread_rb_node into the machine.c file. This hides the implementation of threads from the rest of the code allowing for it to be refactored. Locking discipline is tightened up in this change. As the lock is now encapsulated in threads, the findnew function requires holding it (as it already did in machine). Rather than do conditionals with locks based on whether the thread should be created (which could potentially be error prone with a read lock match with a write unlock), have a separate threads__find that won't create the thread and only holds the read lock. This effectively duplicates the findnew logic, with the existing findnew logic only operating under a write lock assuming creation is necessary as a previous find failed. The creation may still fail with the write lock due to another thread. The duplication is removed in a later next patch that delegates the implementation to hashtable. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Yang Jihong Cc: Oliver Upton Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240301053646.1449657-5-irogers@google.com

perf: util: use capstone disasm engine to show assembly instructions

2024-02-21T02:06:48+00:00

Currently, the instructions of samples are shown as raw hex strings which are hard to read. x86 has a special option '--xed' to disassemble the hex string via intel XED tool. Here we use capstone as our disassembler engine to give more friendly instructions. We select libcapstone because capstone can provide more insn details. Perf will fallback to raw instructions if libcapstone is not available. The advantages compared to XED tool: * Support arm, arm64, x86-32, x86_64 (more could be supported), xed only for x86_64. * Immediate address operands are shown as symbol+offs. Signed-off-by: Changbin Du Reviewed-by: Adrian Hunter Cc: changbin.du@gmail.com Cc: Thomas Richter Cc: Andi Kleen Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240217074046.4100789-3-changbin.du@huawei.com