kernel/git/next/linux-next.git/tools/perf/Documentation, branch master

tools: Port perf ui from GTK 2 to GTK 4

2026-09-09T20:00:04+00:00

Port straight to GTK 4 rather than GTK 3, since GTK 4 is where new development happens and GTK 3 is old itself now. GTK 4 drops GtkContainer, GdkScreen, and the gtk_main()/ gtk_dialog_run() family perf's GTK UI relied on. Containers get per-widget setters (gtk_box_append() and friends), monitor geometry comes from GdkMonitor instead of GdkScreen, and the main and error-dialog loops become explicit GMainLoops quit from the "close-request" and "response" signals. Widgets are visible by default now, so gtk_widget_show_all()/set_no_show_all() go away, and the remaining gtk_widget_show()/gtk_widget_hide() calls become gtk_widget_set_visible() (with a small wrapper where "response" needs to pass gtk_widget_hide() as a callback, since it no longer exists as a plain function). gtk_ui_progress__finish() skips destroying a progress dialog that was never created, since gtk_window_destroy() asserts on NULL where the old widget destroy tolerated it. Two spots the GTK 2 to GTK 3 port had missed (builtin-annotate.c, ui/gtk/setup.c still using HAVE_GTK2_SUPPORT and gtk_main_quit()) are fixed to match. Runtime fallout from the new signal-driven loops: the error dialog's nested loop hung if the parent window closed (GTK_DIALOG_DESTROY_WITH_PARENT destroys without emitting "response"); gtk_info_bar_get_content_area() is gone, breaking GTK_INFO_BAR_SUPPORT; the progress dialog's static widget pointers dangled after a manual close; perf_gtk__error() and the warning functions reused an exhausted va_list when vasprintf() failed. The error loop is tracked in a list instead of a single pointer, since perf_gtk__error() can be called re-entrantly (the dialog isn't modal) and a lone global leaked the outer loop when that happened. The list is only ever touched from the main thread: perf_gtk__error() updates it while handling a dialog, and SIGINT/SIGQUIT/SIGTERM are deferred to a GLib source via g_unix_signal_add() rather than calling perf_gtk__exit() straight out of a real signal handler, so quitting on those signals is serialized with the list update instead of racing it from signal-handler context. SIGSEGV/SIGFPE keep a real handler, since they're synchronous faults with no "later" to defer to, but it's pared down to reporting and reraising the default disposition (perf_gtk__fatal_signal()): there's no safe way to run GTK/GLib code from the faulting context. stdarg.h, stdio.h, and string.h are now included explicitly where used (util.c, hists.c, annotate.c) rather than relying on transitive includes, which musl doesn't guarantee. The gtk4-infobar feature check is dropped: GtkInfoBar has existed unconditionally since GTK 3.10, so the check can only ever pass, and it was failing outright here anyway since gtk_info_bar_new() is deprecated and the check treats deprecation warnings as errors. HAVE_GTK_INFO_BAR_SUPPORT and its statusbar-only fallback go away; the info bar is now built unconditionally. Signed-off-by: Matt Turner Link: https://lore.kernel.org/r/20260908-perf-gtk2-v8-1-e90d5d155f0d@gmail.com [ Fixed up some patch fuzz ] [ Removed gtk2 from FEATURES_DISPLAY, it is opt-in use 'make VF=1' to see if it was detected ] Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add support for displaying weights in annotate

2026-09-04T21:20:29+00:00

Add support for showing all the three possible per IP weights in annotate. The weights are shown by defaults if any are non zero. This is useful, especially with the new insn lat statistics, but also for all the existing weights. Add a hotkey to the interactive browser to turn them off (w), as well as a perf annotate command line option. The weights are stored unconditionally in the sym_hist_entry, which will increase memory consumption somewhat. Reviewed-by: Namhyung Kim Assisted-by: omp:GPT-5.6-Luna Signed-off-by: Andi Kleen Signed-off-by: Arnaldo Carvalho de Melo

perf tools top: Add --weight option

2026-09-04T21:20:06+00:00

Add a -W/--weight option to perf top to collect weights too. Useful with follow on patches. Reviewed-by: Namhyung Kim Assisted-by: omp:GPT-5.6-Luna Signed-off-by: Andi Kleen Signed-off-by: Arnaldo Carvalho de Melo

perf tools record: Modernize -W man page

2026-09-04T21:19:16+00:00

Modernize the -W / --weight description in the manpage to cover more cases that are supported now. Reviewed-by: Namhyung Kim Signed-off-by: Andi Kleen Signed-off-by: Arnaldo Carvalho de Melo

perf c2c: document function view in perf-c2c man page

2026-08-17T23:04:06+00:00

Describe the function view hierarchy (read-side function -> contending writer function -> shared cachelines), the per-level indentation, and the keys, with a worked example. Document that reliable function attribution requires `iaddr` in `--coalesce`, that the reader and writer may be the same function, and why the coalesced function view cannot distinguish same-thread from different-thread accesses in that case. Also document that verbose mode includes code addresses in function rows. Signed-off-by: Jiebin Sun Reviewed-by: Tianyou Li Reviewed-by: Wangyang Guo Reviewed-by: Ian Rogers Cc: Dapeng Mi Cc: James Clark Cc: Thomas Falcon Signed-off-by: Namhyung Kim

perf sched latency: Add histogram and time interval options

2026-08-07T17:56:23+00:00

While 'perf sched latency' reports task runtime and delay statistics (average and maximum delay), it does not provide a visual representation of how task wait times are distributed across latency ranges between snapshots (start and finish of the analysis window). The --histogram option collects CPU wait latencies (time between when a task becomes runnable and when it gets scheduled onto a CPU) into 22 latency buckets, displaying an ASCII bar chart distribution. The --hist-mode option configures the bucketing scheme: - log (default). Logarithmic latency buckets ranging from sub-microsecond (< 1 us) up to >= 1.05 seconds - linear. Equal-width linear latency buckets (i.e., 100 us steps up to >= 2.1 ms) The --time option allows filtering trace event processing to a specific time interval [start,stop]. Example histogram output excerpt: ❯ sudo perf sched latency --histogram --CPU 0 CPU Wait Latency Distribution Histogram (between snapshots) (total samples: 36114) ------------------------------------------------------------------- Latency Range | Count | Pct | Histogram Graph ------------------------------------------------------------------- < 1 us | 17 | 0.0% | # 2 - 4 us | 673 | 1.9% | # 4 - 8 us | 6237 | 17.3% | ###### 8 - 16 us | 3224 | 8.9% | ### 16 - 32 us | 1388 | 3.8% | # 32 - 64 us | 709 | 2.0% | # 64 - 128 us | 690 | 1.9% | # 128 - 256 us | 789 | 2.2% | # 256 - 512 us | 541 | 1.5% | # 512 - 1024 us | 2256 | 6.2% | ## 1 - 2 ms | 3577 | 9.9% | ### 2 - 4 ms | 13259 | 36.7% | ############## 4 - 8 ms | 2523 | 7.0% | ## 8 - 16 ms | 222 | 0.6% | # 16 - 32 ms | 10 | 0.0% | # >= 1.05 s | 3 | 0.0% | # ------------------------------------------------------------------- Reviewed-by: Ian Rogers Signed-off-by: Aaron Tomlin Signed-off-by: Namhyung Kim

perf trace: Add --bitmask-list command-line option

2026-07-24T05:59:42+00:00

Introduce a new '--bitmask-list' command-line option for 'perf trace'. When this option is specified, the formatting of cpumasks is delegated to bitmap_scnprintf(), enabling cpumasks to be displayed as a condensed, human-readable list (e.g., "0,2-5,7") instead of the default hexadecimal representation. An example is provided below: ❯ sudo ./perf trace --show-cpu --bitmask-list --event ipi:ipi_send_cpumask --max-event 5 0.000 [000] Xorg/1434 ipi:ipi_send_cpumask(cpumask: 2-3,6, callsite: 0xffffffff9994f8e4, callback: 0xffffffff9994fdd0) 694.527 [002] chrome/2894 ipi:ipi_send_cpumask(cpumask: 1,3-5, callsite: 0xffffffff9994f8e4, callback: 0xffffffff9994fdd0) 2666.608 [003] Chrome_ChildIO/2948 ipi:ipi_send_cpumask(cpumask: 4,7, callsite: 0xffffffff9994f8e4, callback: 0xffffffff9994fdd0) 2673.638 [000] Chrome_IOThrea/2920 ipi:ipi_send_cpumask(cpumask: 2-5, callsite: 0xffffffff9994f8e4, callback: 0xffffffff9994fdd0) 2714.228 [005] chrome/3375 ipi:ipi_send_cpumask(cpumask: 0-4,6-7, callsite: 0xffffffff9994f8e4, callback: 0xffffffff9994fdd0) Signed-off-by: Aaron Tomlin Signed-off-by: Namhyung Kim

perf stat: Add --hide-zero-events option to suppress zero-count events

2026-07-20T04:49:30+00:00

When monitoring a large number of events (e.g., with wildcards such as --event 'syscalls:sys_enter_*'), many matched events will return a count of zero. This clutters the output, making it difficult to spot the active events. Add a new option --hide-zero-events to suppress printing events that have a count of zero. To prevent formatting and diagnostic issues, the zero-skipping logic implements the following rules: 1. In metric-only mode (i.e., --metric-only), columns must remain aligned in the output grid. We evaluate config->metric_only first to avoid skipping zero-valued columns, preventing values from shifting left and aligning under incorrect headers 2. For explicitly requested events, we ensure they are not silently hidden if they are unsupported. We only hide a zero-count event if counter->supported is true, ensuring that unsupported explicit events still report "" Signed-off-by: Aaron Tomlin Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf doc: Fix mmap failure checks in topdown example

2026-07-15T18:16:41+00:00

Use MAP_FAILED instead of NULL to detect mmap errors, and fix the slots_p variable name typo in the sample code. Signed-off-by: Hongfu Li Signed-off-by: Namhyung Kim

perf test: Add Arm CoreSight callchain test

2026-07-03T23:52:00+00:00

Add a CoreSight shell test for synthesized callchains. The test uses the new callchain workload to generate trace and decodes it with synthesis callchain. It then verifies that the instruction samples show the expected callchain push and pop. Use control FIFOs so tracing starts only around the workload, which keeps the trace data small. The test is limited to with the cs_etm event available and root permission. After: perf test 138 -vvv 138: CoreSight synthesized callchain: ---- start ---- test child forked, pid 35581 Callchain flow matched: l1=4642868 l2=4642880 l3=4642895 l4=4642919 l5=4670494 l6=4670500 l7=4670520 ---- end(0) ---- 138: CoreSight synthesized callchain : Ok Assisted-by: Codex:GPT-5.5 Reviewed-by: James Clark Signed-off-by: Leo Yan Signed-off-by: Namhyung Kim