[PATCH v9 8/9] perf c2c: add function view browser UI and cacheline detail

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 <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Dapeng Mi <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Falcon <[email protected]>
Reviewed-by: Tianyou Li <[email protected]>
Reviewed-by: Wangyang Guo <[email protected]>
---
 tools/perf/builtin-c2c.c              |  10 ++
 tools/perf/ui/browsers/Build          |   1 +
 tools/perf/ui/browsers/c2c-function.c | 209 ++++++++++++++++++++++++++
 tools/perf/util/c2c.h                 |  22 +++
 4 files changed, 242 insertions(+)
 create mode 100644 tools/perf/ui/browsers/c2c-function.c

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 16b00a36fdfc..715b75d42f2a 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -2745,11 +2745,18 @@ perf_c2c_browser__new(struct hists *hists)
 
 static int perf_c2c__hists_browse(struct hists *hists)
 {
+	struct c2c_function_view_args func_args = {
+		.cl_hists	  = &c2c.hists,
+		.cl_sort	  = c2c.cl_sort,
+		.symbol_full	  = c2c.symbol_full,
+		.browse_cacheline = perf_c2c__browse_cacheline,
+	};
 	struct hist_browser *browser;
 	int key = -1;
 	static const char help[] =
 	" d             Display cacheline details \n"
 	" ENTER         Toggle callchains (if present) \n"
+	" TAB           Switch to function view\n"
 	" q             Quit \n";
 
 	browser = perf_c2c_browser__new(hists);
@@ -2771,6 +2778,9 @@ static int perf_c2c__hists_browse(struct hists *hists)
 		case 'd':
 			perf_c2c__browse_cacheline(browser->he_selection);
 			break;
+		case '\t':
+			perf_c2c__browse_function_view(&func_args);
+			break;
 		case '?':
 			ui_browser__help_window(&browser->b, help);
 			break;
diff --git a/tools/perf/ui/browsers/Build b/tools/perf/ui/browsers/Build
index a07489e44765..ae67a2161f7d 100644
--- a/tools/perf/ui/browsers/Build
+++ b/tools/perf/ui/browsers/Build
@@ -5,3 +5,4 @@ perf-ui-y += map.o
 perf-ui-y += scripts.o
 perf-ui-y += header.o
 perf-ui-y += res_sample.o
+perf-ui-y += c2c-function.o
diff --git a/tools/perf/ui/browsers/c2c-function.c b/tools/perf/ui/browsers/c2c-function.c
new file mode 100644
index 000000000000..3d23e9d84981
--- /dev/null
+++ b/tools/perf/ui/browsers/c2c-function.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * C2C function browser - TUI front end for function-level sharing analysis
+ */
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <sys/ttydefaults.h>
+#include <linux/rbtree.h>
+#include <linux/zalloc.h>
+
+#include "../browser.h"
+#include "../keysyms.h"
+#include "../libslang.h"
+#include "../ui.h"
+#include "../../util/c2c.h"
+#include "../../util/debug.h"
+#include "../../util/hist.h"
+#include "../../util/symbol.h"
+#include "hists.h"
+
+struct c2c_function_browser {
+	struct hist_browser	hb;
+	unsigned int		(*orig_refresh)(struct ui_browser *browser);
+	int			(*browse_cacheline)(struct hist_entry *he);
+};
+
+/*
+ * Count visible entries in @root, descending only through visible, unfolded
+ * parents. Match hists__filter_entries(), which drives generic browser
+ * navigation, so the count cannot include rows the browser skips.
+ */
+static u64
+c2c_function__nr_visible_rows(struct rb_root_cached *root, float min_pcnt)
+{
+	struct rb_node *nd;
+	u64 rows = 0;
+
+	for (nd = rb_first_cached(root); nd; nd = rb_next(nd)) {
+		struct hist_entry *he = rb_entry(nd, struct hist_entry, rb_node);
+
+		/*
+		 * The generic refresh folds filtered parents and therefore hides
+		 * their subtree. A percentage-rejected parent is merely skipped;
+		 * if it is unfolded, qualifying descendants are still rendered.
+		 */
+		if (he->filtered)
+			continue;
+
+		if (hist_entry__get_percent_limit(he) >= min_pcnt)
+			rows++;
+		if (he->has_children && he->unfolded)
+			rows += c2c_function__nr_visible_rows(&he->hroot_out,
+							     min_pcnt);
+	}
+	return rows;
+}
+
+static void
+c2c_function_browser__update_nr_entries(struct c2c_function_browser *browser)
+{
+	u64 nr_entries;
+
+	nr_entries = c2c_function__nr_visible_rows(&browser->hb.hists->entries,
+						   browser->hb.min_pcnt);
+	browser->hb.nr_non_filtered_entries = nr_entries;
+	browser->hb.b.nr_entries = nr_entries;
+}
+
+static unsigned int c2c_function_browser__refresh(struct ui_browser *ui_browser)
+{
+	struct hist_browser *hist_browser = container_of(ui_browser, struct hist_browser, b);
+	struct c2c_function_browser *browser;
+
+	browser = container_of(hist_browser, struct c2c_function_browser, hb);
+	c2c_function_browser__update_nr_entries(browser);
+	return browser->orig_refresh(ui_browser);
+}
+
+static int c2c_function_browser__title(struct hist_browser *browser,
+				       char *bf, size_t size)
+{
+	scnprintf(bf, size,
+		  "Shared Data Functions Table     (%" PRIu64 " entries, sorted on Cycles %%)",
+		  browser->hists->nr_non_filtered_entries);
+	return 0;
+}
+
+static struct c2c_function_browser *
+c2c_function_browser__new(struct hists *hists,
+			  int (*browse_cacheline)(struct hist_entry *he))
+{
+	struct c2c_function_browser *browser;
+
+	if (!hists)
+		return NULL;
+
+	browser = zalloc(sizeof(*browser));
+	if (!browser)
+		return NULL;
+
+	hist_browser__init(&browser->hb, hists);
+	browser->orig_refresh = browser->hb.b.refresh;
+	browser->hb.b.refresh = c2c_function_browser__refresh;
+	browser->browse_cacheline = browse_cacheline;
+
+	browser->hb.title = c2c_function_browser__title;
+	browser->hb.c2c_filter = true;
+	browser->hb.show_headers = true;
+	/* Keep title line count consistent with forcing headers on. */
+	browser->hb.b.extra_title_lines = hists->hpp_list->nr_header_lines;
+	browser->hb.min_pcnt = 0.0;
+
+	return browser;
+}
+
+static void c2c_function_browser__delete(struct c2c_function_browser *browser)
+{
+	free(browser);
+}
+
+static int
+c2c_browser__browse_cacheline(struct c2c_function_browser *browser,
+			      struct hist_entry *he_selection)
+{
+	struct hist_entry *he = c2c_function__find_cacheline(he_selection);
+
+	return he ? browser->browse_cacheline(he) : -1;
+}
+
+int perf_c2c__browse_function_view(struct c2c_function_view_args *args)
+{
+	struct c2c_function_browser *browser;
+	struct hists *hists;
+	bool saved_use_callchain = symbol_conf.use_callchain;
+	int key, ret;
+	static const char help[] =
+	" d             Display details for the selected level-3 cacheline\n"
+	" e/+           Expand/collapse the selected entry\n"
+	" TAB/ESC/q/^C  Return to the cacheline view\n";
+
+	if (!args || !args->cl_hists || !args->browse_cacheline)
+		return -EINVAL;
+
+	/*
+	 * Function view does not display callchains; cacheline detail temporarily
+	 * restores them.
+	 */
+	symbol_conf.use_callchain = false;
+
+	ret = c2c_function__build(args->cl_hists, args->cl_sort,
+				  args->symbol_full, &hists);
+	if (ret) {
+		if (ret == -EOPNOTSUPP)
+			ui__warning("The function view requires iaddr in --coalesce.\n");
+		else
+			ui__error("Failed to build function view hierarchy (ret=%d)\n", ret);
+		goto out;
+	}
+
+	browser = c2c_function_browser__new(hists, args->browse_cacheline);
+	if (!browser) {
+		ret = -ENOMEM;
+		goto out_reset;
+	}
+
+	/* Reset abort key so we can receive Ctrl-C as a key. */
+	SLang_reset_tty();
+	SLang_init_tty(0, 0, 0);
+	SLtty_set_suspend_state(true);
+
+	while (1) {
+		c2c_function_browser__update_nr_entries(browser);
+		key = hist_browser__run(&browser->hb, "? - help", true, 0);
+
+		switch (key) {
+		case 'q':
+		case K_TAB:
+		case K_ESC:
+		case CTRL('c'):
+			goto browser_done;
+		case 'd':
+			/* Cacheline detail honors the user's callchain setting. */
+			symbol_conf.use_callchain = saved_use_callchain;
+			c2c_browser__browse_cacheline(browser, browser->hb.he_selection);
+			/*
+			 * Preserve any toggle made in the detail view, then
+			 * re-disable callchain for the function view.
+			 */
+			saved_use_callchain = symbol_conf.use_callchain;
+			symbol_conf.use_callchain = false;
+			break;
+		case '?':
+			ui_browser__help_window(&browser->hb.b, help);
+			break;
+		default:
+			break;
+		}
+	}
+
+browser_done:
+	c2c_function_browser__delete(browser);
+out_reset:
+	c2c_function__reset();
+out:
+	symbol_conf.use_callchain = saved_use_callchain;
+	return ret;
+}
diff --git a/tools/perf/util/c2c.h b/tools/perf/util/c2c.h
index 6548b9ba81f1..53f024e25d99 100644
--- a/tools/perf/util/c2c.h
+++ b/tools/perf/util/c2c.h
@@ -110,4 +110,26 @@ void c2c_function__reset(void);
 /* Valid only between a successful build and c2c_function__reset(). */
 struct hist_entry *c2c_function__find_cacheline(struct hist_entry *he);
 
+/* Inputs and TUI callback supplied by the c2c command. */
+struct c2c_function_view_args {
+	/* Source cacheline histograms used by the common model. */
+	struct c2c_hists	*cl_hists;
+	/* --coalesce field list, used to require iaddr. */
+	const char		*cl_sort;
+	/* Do not cap long symbol names. */
+	bool			 symbol_full;
+	/* Open the cacheline detail view for @he. */
+	int			(*browse_cacheline)(struct hist_entry *he);
+};
+
+#ifdef HAVE_SLANG_SUPPORT
+int perf_c2c__browse_function_view(struct c2c_function_view_args *args);
+#else
+static inline int
+perf_c2c__browse_function_view(struct c2c_function_view_args *args __maybe_unused)
+{
+	return 0;
+}
+#endif
+
 #endif /* __PERF_UTIL_C2C_H */
-- 
2.52.0