kernel/git/stable/linux.git/tools/perf/util/c2c-function.c, branch master

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