kernel/git/stable/linux.git/tools/perf/util, branch master

perf evlist: Warn when 'sleep' workload is used without system-wide (-a) option

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

A common mistake when trying to record system-wide profiles for a given duration is running commands like 'perf record sleep 1' or 'perf stat sleep 1' without passing '-a' / '--all-cpus'. When '-a' is omitted, perf defaults to per-process monitoring of the sleep process itself, which does not collect system-wide activity and records very few events. Add a warning in evlist__prepare_workload() when the workload executable is 'sleep' and system-wide mode is not enabled. Assisted-by: Antigravity:gemini-3.6-flash Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf c2c: add function view browser UI and cacheline detail

2026-08-17T23:04:05+00:00

Add the browser front end: create/run/delete the hist_browser and add the title. The d shortcut opens the existing per-cacheline detail view for the selected level-3 cacheline. Level-3 entries retain the source cacheline index, so the shortcut can locate the original entry without relying on a potentially ambiguous virtual address. Report a warning when the common model rejects a cacheline coalescing field list without `iaddr`. Without it, the detail histograms may already have merged samples from different functions and cannot support reliable function attribution. Keep visible-row accounting local to the function view by wrapping the generic browser refresh callback and recounting the currently reachable hierarchy before each redraw. This keeps navigation correct when a level-1 row is collapsed while level-3 descendants remain expanded, without adding C2C-specific hooks to the shared hist_browser. Also handle Ctrl-C like the other function-view exit keys. Keep callchains hidden while the function browser runs, restoring the user's setting while opening the cacheline detail view. Wire the builder into perf_c2c__browse_function_view(). 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 c2c: build and finalize the function view hierarchy

2026-08-17T23:04:05+00:00

Add the builder that walks the top-level cacheline entries and, for each read-side function, correlates the functions that write the same lines (level 2) and the specific cachelines they contend over (level 3) within each retained detail histogram. Aggregate the write traffic per contending function, resort by store count, and prune writers/functions with no contention. The finalize pass then computes the Cycles % denominator from the surviving level-1 entries after pruning, so the column shows each function's share of the functions retained in the table rather than of the whole recording -- the semantics documented for Cycles % in perf-c2c.txt. Expose c2c_function__build() and c2c_function__reset() for the TUI front end added by the next patch. The builder requires iaddr in the cacheline coalescing fields and returns the completed hists through an output argument. Validate the inputs before replacing an existing model. Function-view entries do not carry callchains. Suppress callchain handling while building and tearing down the model so the common API does not depend on the caller's current callchain setting. 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 c2c: add function view hierarchy entry creation

2026-08-17T23:04:05+00:00

Add the entry-creation layer: owned-reference child allocation and insertion, and the level-1/2/3 lookup-or-create functions keyed by function symbol (level 1 read-side, level 2 writer) and by the source cacheline's existing index (level 3). Give synthetic children normal entry operations and acquire their thread and map-symbol references. This lets the hierarchy teardown use hist_entry__delete() for the common fields while the function-view free callback handles the private child tree and containing allocation. Reuse cacheline_idx to preserve the source entry identity without adding function-view-only state. Add c2c_function__find_cacheline() to locate the original cacheline entry by the same index. These are driven by the hierarchy builder in the next patch and are __maybe_unused until then. 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 c2c: add function view stats merge and memory management

2026-08-17T23:04:05+00:00

Add the per-entry stats/cstats aggregation helpers and hierarchy teardown. Child common fields are released through hist_entry__delete(), while the function-view free callback handles the private child tree and containing allocation. Also add a helper for pruning writer entries with no stores or cacheline children. These are used by the entry-creation and builder patches that follow and are __maybe_unused until then. 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 c2c: add HPP list parsing for function view columns

2026-08-17T23:04:05+00:00

Add the parser that builds the function view's local HPP output and sort lists from field strings. This includes dimension lookup, comparator wrappers, c2c_fmt allocation, and the initialization entry points used by the hierarchy builder. The generic perf_hpp__setup_output_field() registers formats on the global perf_hpp_list. Using it here would leave the function view's local list without output columns and modify the cacheline view's list instead. Add c2c_function_hists__setup_output_field() to append sort keys to the local output list. 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 c2c: add column rendering for function view

2026-08-17T23:04:05+00:00

Add renderers for the function view's Cycles %, Store count, and hierarchy identity columns. The identity column renders the read-side function, contending writer, or cacheline, with indentation for the hierarchy level. Also add width and header helpers, estimated-cycle calculation, comparators, and the dimension table that ties them together. Clamp the identity renderer's returned length to its local buffer before using it for pointer and padding calculations. This handles snprintf-style would-have-been lengths without changing normal output. The next patch connects these dimensions to the view's HPP lists, so the symbols used only there are temporarily marked __maybe_unused. 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 c2c: add function view model skeleton

2026-08-17T23:03:42+00:00

Add the initial common model for the c2c function view: model state and small helpers shared by the hierarchy construction and formatting added in later patches. Build the model from util/ so it remains independent of the TUI and command-private symbols. 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 c2c: extract shared data structures into util/c2c.h

2026-08-17T22:07:08+00:00

The function browser belongs in libperf-ui.a, but that archive is also linked into python/perf.so, where builtin command objects are unavailable. The browser therefore cannot depend on types or callbacks owned by builtin-c2c.c. Move c2c_hists, compute_stats, c2c_hist_entry, and the shared column formatting definitions from builtin-c2c.c to a new util/c2c.h. Move c2c_fmt_free() and c2c_fmt_equal() to a new util/c2c.c. Keep struct perf_c2c, the command instance, and perf_c2c__browse_cacheline() private to builtin-c2c.c. No functional change. 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 dso: Replace assert with runtime check in dso__read_symbol()

2026-08-15T13:37:14+00:00

dso__read_symbol() asserts that len <= jited_prog_len, where len comes from sym->end - sym->start (parsed from PERF_RECORD_KSYMBOL in perf.data). Both values originate from untrusted file input. With NDEBUG (production builds), the assert is compiled out, allowing an out-of-bounds heap read when the BPF program buffer is accessed. Without NDEBUG, a crafted perf.data crashes perf with an assertion failure. Replace the assert with a runtime bounds check that returns NULL with an appropriate error code, matching the existing error handling pattern in this function. Fixes: aa04707f507e ("perf dso: Support BPF programs in dso__read_symbol()") Reported-by: sashiko-bot Reviewed-by: Ian Rogers Cc: Song Liu Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim