xref: /linux/tools/perf/ui/browsers/hists.c (revision e8e684a58b9bddde3fdb1a65cd26eb7a3e1e746e)

#include <stdio.h>
#include "../libslang.h"
#include <stdlib.h>
#include <string.h>
#include <linux/rbtree.h>

#include "../../util/evsel.h"
#include "../../util/evlist.h"
#include "../../util/hist.h"
#include "../../util/pstack.h"
#include "../../util/sort.h"
#include "../../util/util.h"
#include "../../arch/common.h"

#include "../browser.h"
#include "../helpline.h"
#include "../util.h"
#include "../ui.h"
#include "map.h"

struct hist_browser {
	struct ui_browser   b;
	struct hists	    *hists;
	struct hist_entry   *he_selection;
	struct map_symbol   *selection;
	int		     print_seq;
	bool		     show_dso;
	float		     min_pcnt;
	u64		     nr_pcnt_entries;
};

extern void hist_browser__init_hpp(void);

static int hists__browser_title(struct hists *hists, char *bf, size_t size,
				const char *ev_name);

static void hist_browser__refresh_dimensions(struct hist_browser *browser)
{
	/* 3 == +/- toggle symbol before actual hist_entry rendering */
	browser->b.width = 3 + (hists__sort_list_width(browser->hists) +
			     sizeof("[k]"));
}

static void hist_browser__reset(struct hist_browser *browser)
{
	browser->b.nr_entries = browser->hists->nr_entries;
	hist_browser__refresh_dimensions(browser);
	ui_browser__reset_index(&browser->b);
}

static char tree__folded_sign(bool unfolded)
{
	return unfolded ? '-' : '+';
}

static char map_symbol__folded(const struct map_symbol *ms)
{
	return ms->has_children ? tree__folded_sign(ms->unfolded) : ' ';
}

static char hist_entry__folded(const struct hist_entry *he)
{
	return map_symbol__folded(&he->ms);
}

static char callchain_list__folded(const struct callchain_list *cl)
{
	return map_symbol__folded(&cl->ms);
}

static void map_symbol__set_folding(struct map_symbol *ms, bool unfold)
{
	ms->unfolded = unfold ? ms->has_children : false;
}

static int callchain_node__count_rows_rb_tree(struct callchain_node *node)
{
	int n = 0;
	struct rb_node *nd;

	for (nd = rb_first(&node->rb_root); nd; nd = rb_next(nd)) {
		struct callchain_node *child = rb_entry(nd, struct callchain_node, rb_node);
		struct callchain_list *chain;
		char folded_sign = ' '; /* No children */

		list_for_each_entry(chain, &child->val, list) {
			++n;
			/* We need this because we may not have children */
			folded_sign = callchain_list__folded(chain);
			if (folded_sign == '+')
				break;
		}

		if (folded_sign == '-') /* Have children and they're unfolded */
			n += callchain_node__count_rows_rb_tree(child);
	}

	return n;
}

static int callchain_node__count_rows(struct callchain_node *node)
{
	struct callchain_list *chain;
	bool unfolded = false;
	int n = 0;

	list_for_each_entry(chain, &node->val, list) {
		++n;
		unfolded = chain->ms.unfolded;
	}

	if (unfolded)
		n += callchain_node__count_rows_rb_tree(node);

	return n;
}

static int callchain__count_rows(struct rb_root *chain)
{
	struct rb_node *nd;
	int n = 0;

	for (nd = rb_first(chain); nd; nd = rb_next(nd)) {
		struct callchain_node *node = rb_entry(nd, struct callchain_node, rb_node);
		n += callchain_node__count_rows(node);
	}

	return n;
}

static bool map_symbol__toggle_fold(struct map_symbol *ms)
{
	if (!ms)
		return false;

	if (!ms->has_children)
		return false;

	ms->unfolded = !ms->unfolded;
	return true;
}

static void callchain_node__init_have_children_rb_tree(struct callchain_node *node)
{
	struct rb_node *nd = rb_first(&node->rb_root);

	for (nd = rb_first(&node->rb_root); nd; nd = rb_next(nd)) {
		struct callchain_node *child = rb_entry(nd, struct callchain_node, rb_node);
		struct callchain_list *chain;
		bool first = true;

		list_for_each_entry(chain, &child->val, list) {
			if (first) {
				first = false;
				chain->ms.has_children = chain->list.next != &child->val ||
							 !RB_EMPTY_ROOT(&child->rb_root);
			} else
				chain->ms.has_children = chain->list.next == &child->val &&
							 !RB_EMPTY_ROOT(&child->rb_root);
		}

		callchain_node__init_have_children_rb_tree(child);
	}
}

static void callchain_node__init_have_children(struct callchain_node *node)
{
	struct callchain_list *chain;

	list_for_each_entry(chain, &node->val, list)
		chain->ms.has_children = !RB_EMPTY_ROOT(&node->rb_root);

	callchain_node__init_have_children_rb_tree(node);
}

static void callchain__init_have_children(struct rb_root *root)
{
	struct rb_node *nd;

	for (nd = rb_first(root); nd; nd = rb_next(nd)) {
		struct callchain_node *node = rb_entry(nd, struct callchain_node, rb_node);
		callchain_node__init_have_children(node);
	}
}

static void hist_entry__init_have_children(struct hist_entry *he)
{
	if (!he->init_have_children) {
		he->ms.has_children = !RB_EMPTY_ROOT(&he->sorted_chain);
		callchain__init_have_children(&he->sorted_chain);
		he->init_have_children = true;
	}
}

static bool hist_browser__toggle_fold(struct hist_browser *browser)
{
	if (map_symbol__toggle_fold(browser->selection)) {
		struct hist_entry *he = browser->he_selection;

		hist_entry__init_have_children(he);
		browser->hists->nr_entries -= he->nr_rows;

		if (he->ms.unfolded)
			he->nr_rows = callchain__count_rows(&he->sorted_chain);
		else
			he->nr_rows = 0;
		browser->hists->nr_entries += he->nr_rows;
		browser->b.nr_entries = browser->hists->nr_entries;

		return true;
	}

	/* If it doesn't have children, no toggling performed */
	return false;
}

static int callchain_node__set_folding_rb_tree(struct callchain_node *node, bool unfold)
{
	int n = 0;
	struct rb_node *nd;

	for (nd = rb_first(&node->rb_root); nd; nd = rb_next(nd)) {
		struct callchain_node *child = rb_entry(nd, struct callchain_node, rb_node);
		struct callchain_list *chain;
		bool has_children = false;

		list_for_each_entry(chain, &child->val, list) {
			++n;
			map_symbol__set_folding(&chain->ms, unfold);
			has_children = chain->ms.has_children;
		}

		if (has_children)
			n += callchain_node__set_folding_rb_tree(child, unfold);
	}

	return n;
}

static int callchain_node__set_folding(struct callchain_node *node, bool unfold)
{
	struct callchain_list *chain;
	bool has_children = false;
	int n = 0;

	list_for_each_entry(chain, &node->val, list) {
		++n;
		map_symbol__set_folding(&chain->ms, unfold);
		has_children = chain->ms.has_children;
	}

	if (has_children)
		n += callchain_node__set_folding_rb_tree(node, unfold);

	return n;
}

static int callchain__set_folding(struct rb_root *chain, bool unfold)
{
	struct rb_node *nd;
	int n = 0;

	for (nd = rb_first(chain); nd; nd = rb_next(nd)) {
		struct callchain_node *node = rb_entry(nd, struct callchain_node, rb_node);
		n += callchain_node__set_folding(node, unfold);
	}

	return n;
}

static void hist_entry__set_folding(struct hist_entry *he, bool unfold)
{
	hist_entry__init_have_children(he);
	map_symbol__set_folding(&he->ms, unfold);

	if (he->ms.has_children) {
		int n = callchain__set_folding(&he->sorted_chain, unfold);
		he->nr_rows = unfold ? n : 0;
	} else
		he->nr_rows = 0;
}

static void hists__set_folding(struct hists *hists, bool unfold)
{
	struct rb_node *nd;

	hists->nr_entries = 0;

	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
		struct hist_entry *he = rb_entry(nd, struct hist_entry, rb_node);
		hist_entry__set_folding(he, unfold);
		hists->nr_entries += 1 + he->nr_rows;
	}
}

static void hist_browser__set_folding(struct hist_browser *browser, bool unfold)
{
	hists__set_folding(browser->hists, unfold);
	browser->b.nr_entries = browser->hists->nr_entries;
	/* Go to the start, we may be way after valid entries after a collapse */
	ui_browser__reset_index(&browser->b);
}

static void ui_browser__warn_lost_events(struct ui_browser *browser)
{
	ui_browser__warning(browser, 4,
		"Events are being lost, check IO/CPU overload!\n\n"
		"You may want to run 'perf' using a RT scheduler policy:\n\n"
		" perf top -r 80\n\n"
		"Or reduce the sampling frequency.");
}

static void hist_browser__update_pcnt_entries(struct hist_browser *hb);

static int hist_browser__run(struct hist_browser *browser, const char *ev_name,
			     struct hist_browser_timer *hbt)
{
	int key;
	char title[160];
	int delay_secs = hbt ? hbt->refresh : 0;

	browser->b.entries = &browser->hists->entries;
	browser->b.nr_entries = browser->hists->nr_entries;
	if (browser->min_pcnt)
		browser->b.nr_entries = browser->nr_pcnt_entries;

	hist_browser__refresh_dimensions(browser);
	hists__browser_title(browser->hists, title, sizeof(title), ev_name);

	if (ui_browser__show(&browser->b, title,
			     "Press '?' for help on key bindings") < 0)
		return -1;

	while (1) {
		key = ui_browser__run(&browser->b, delay_secs);

		switch (key) {
		case K_TIMER: {
			u64 nr_entries;
			hbt->timer(hbt->arg);

			if (browser->min_pcnt) {
				hist_browser__update_pcnt_entries(browser);
				nr_entries = browser->nr_pcnt_entries;
			} else {
				nr_entries = browser->hists->nr_entries;
			}

			ui_browser__update_nr_entries(&browser->b, nr_entries);

			if (browser->hists->stats.nr_lost_warned !=
			    browser->hists->stats.nr_events[PERF_RECORD_LOST]) {
				browser->hists->stats.nr_lost_warned =
					browser->hists->stats.nr_events[PERF_RECORD_LOST];
				ui_browser__warn_lost_events(&browser->b);
			}

			hists__browser_title(browser->hists, title, sizeof(title), ev_name);
			ui_browser__show_title(&browser->b, title);
			continue;
		}
		case 'D': { /* Debug */
			static int seq;
			struct hist_entry *h = rb_entry(browser->b.top,
							struct hist_entry, rb_node);
			ui_helpline__pop();
			ui_helpline__fpush("%d: nr_ent=(%d,%d), height=%d, idx=%d, fve: idx=%d, row_off=%d, nrows=%d",
					   seq++, browser->b.nr_entries,
					   browser->hists->nr_entries,
					   browser->b.height,
					   browser->b.index,
					   browser->b.top_idx,
					   h->row_offset, h->nr_rows);
		}
			break;
		case 'C':
			/* Collapse the whole world. */
			hist_browser__set_folding(browser, false);
			break;
		case 'E':
			/* Expand the whole world. */
			hist_browser__set_folding(browser, true);
			break;
		case K_ENTER:
			if (hist_browser__toggle_fold(browser))
				break;
			/* fall thru */
		default:
			goto out;
		}
	}
out:
	ui_browser__hide(&browser->b);
	return key;
}

static char *callchain_list__sym_name(struct callchain_list *cl,
				      char *bf, size_t bfsize, bool show_dso)
{
	int printed;

	if (cl->ms.sym)
		printed = scnprintf(bf, bfsize, "%s", cl->ms.sym->name);
	else
		printed = scnprintf(bf, bfsize, "%#" PRIx64, cl->ip);

	if (show_dso)
		scnprintf(bf + printed, bfsize - printed, " %s",
			  cl->ms.map ? cl->ms.map->dso->short_name : "unknown");

	return bf;
}

#define LEVEL_OFFSET_STEP 3

static int hist_browser__show_callchain_node_rb_tree(struct hist_browser *browser,
						     struct callchain_node *chain_node,
						     u64 total, int level,
						     unsigned short row,
						     off_t *row_offset,
						     bool *is_current_entry)
{
	struct rb_node *node;
	int first_row = row, width, offset = level * LEVEL_OFFSET_STEP;
	u64 new_total, remaining;

	if (callchain_param.mode == CHAIN_GRAPH_REL)
		new_total = chain_node->children_hit;
	else
		new_total = total;

	remaining = new_total;
	node = rb_first(&chain_node->rb_root);
	while (node) {
		struct callchain_node *child = rb_entry(node, struct callchain_node, rb_node);
		struct rb_node *next = rb_next(node);
		u64 cumul = callchain_cumul_hits(child);
		struct callchain_list *chain;
		char folded_sign = ' ';
		int first = true;
		int extra_offset = 0;

		remaining -= cumul;

		list_for_each_entry(chain, &child->val, list) {
			char bf[1024], *alloc_str;
			const char *str;
			int color;
			bool was_first = first;

			if (first)
				first = false;
			else
				extra_offset = LEVEL_OFFSET_STEP;

			folded_sign = callchain_list__folded(chain);
			if (*row_offset != 0) {
				--*row_offset;
				goto do_next;
			}

			alloc_str = NULL;
			str = callchain_list__sym_name(chain, bf, sizeof(bf),
						       browser->show_dso);
			if (was_first) {
				double percent = cumul * 100.0 / new_total;

				if (asprintf(&alloc_str, "%2.2f%% %s", percent, str) < 0)
					str = "Not enough memory!";
				else
					str = alloc_str;
			}

			color = HE_COLORSET_NORMAL;
			width = browser->b.width - (offset + extra_offset + 2);
			if (ui_browser__is_current_entry(&browser->b, row)) {
				browser->selection = &chain->ms;
				color = HE_COLORSET_SELECTED;
				*is_current_entry = true;
			}

			ui_browser__set_color(&browser->b, color);
			ui_browser__gotorc(&browser->b, row, 0);
			slsmg_write_nstring(" ", offset + extra_offset);
			slsmg_printf("%c ", folded_sign);
			slsmg_write_nstring(str, width);
			free(alloc_str);

			if (++row == browser->b.height)
				goto out;
do_next:
			if (folded_sign == '+')
				break;
		}

		if (folded_sign == '-') {
			const int new_level = level + (extra_offset ? 2 : 1);
			row += hist_browser__show_callchain_node_rb_tree(browser, child, new_total,
									 new_level, row, row_offset,
									 is_current_entry);
		}
		if (row == browser->b.height)
			goto out;
		node = next;
	}
out:
	return row - first_row;
}

static int hist_browser__show_callchain_node(struct hist_browser *browser,
					     struct callchain_node *node,
					     int level, unsigned short row,
					     off_t *row_offset,
					     bool *is_current_entry)
{
	struct callchain_list *chain;
	int first_row = row,
	     offset = level * LEVEL_OFFSET_STEP,
	     width = browser->b.width - offset;
	char folded_sign = ' ';

	list_for_each_entry(chain, &node->val, list) {
		char bf[1024], *s;
		int color;

		folded_sign = callchain_list__folded(chain);

		if (*row_offset != 0) {
			--*row_offset;
			continue;
		}

		color = HE_COLORSET_NORMAL;
		if (ui_browser__is_current_entry(&browser->b, row)) {
			browser->selection = &chain->ms;
			color = HE_COLORSET_SELECTED;
			*is_current_entry = true;
		}

		s = callchain_list__sym_name(chain, bf, sizeof(bf),
					     browser->show_dso);
		ui_browser__gotorc(&browser->b, row, 0);
		ui_browser__set_color(&browser->b, color);
		slsmg_write_nstring(" ", offset);
		slsmg_printf("%c ", folded_sign);
		slsmg_write_nstring(s, width - 2);

		if (++row == browser->b.height)
			goto out;
	}

	if (folded_sign == '-')
		row += hist_browser__show_callchain_node_rb_tree(browser, node,
								 browser->hists->stats.total_period,
								 level + 1, row,
								 row_offset,
								 is_current_entry);
out:
	return row - first_row;
}

static int hist_browser__show_callchain(struct hist_browser *browser,
					struct rb_root *chain,
					int level, unsigned short row,
					off_t *row_offset,
					bool *is_current_entry)
{
	struct rb_node *nd;
	int first_row = row;

	for (nd = rb_first(chain); nd; nd = rb_next(nd)) {
		struct callchain_node *node = rb_entry(nd, struct callchain_node, rb_node);

		row += hist_browser__show_callchain_node(browser, node, level,
							 row, row_offset,
							 is_current_entry);
		if (row == browser->b.height)
			break;
	}

	return row - first_row;
}

struct hpp_arg {
	struct ui_browser *b;
	char folded_sign;
	bool current_entry;
};

static int __hpp__color_callchain(struct hpp_arg *arg)
{
	if (!symbol_conf.use_callchain)
		return 0;

	slsmg_printf("%c ", arg->folded_sign);
	return 2;
}

static int __hpp__color_fmt(struct perf_hpp *hpp, struct hist_entry *he,
			    u64 (*get_field)(struct hist_entry *),
			    int (*callchain_cb)(struct hpp_arg *))
{
	int ret = 0;
	double percent = 0.0;
	struct hists *hists = he->hists;
	struct hpp_arg *arg = hpp->ptr;

	if (hists->stats.total_period)
		percent = 100.0 * get_field(he) / hists->stats.total_period;

	ui_browser__set_percent_color(arg->b, percent, arg->current_entry);

	if (callchain_cb)
		ret += callchain_cb(arg);

	ret += scnprintf(hpp->buf, hpp->size, "%6.2f%%", percent);
	slsmg_printf("%s", hpp->buf);

	if (symbol_conf.event_group) {
		int prev_idx, idx_delta;
		struct perf_evsel *evsel = hists_to_evsel(hists);
		struct hist_entry *pair;
		int nr_members = evsel->nr_members;

		if (nr_members <= 1)
			goto out;

		prev_idx = perf_evsel__group_idx(evsel);

		list_for_each_entry(pair, &he->pairs.head, pairs.node) {
			u64 period = get_field(pair);
			u64 total = pair->hists->stats.total_period;

			if (!total)
				continue;

			evsel = hists_to_evsel(pair->hists);
			idx_delta = perf_evsel__group_idx(evsel) - prev_idx - 1;

			while (idx_delta--) {
				/*
				 * zero-fill group members in the middle which
				 * have no sample
				 */
				ui_browser__set_percent_color(arg->b, 0.0,
							arg->current_entry);
				ret += scnprintf(hpp->buf, hpp->size,
						 " %6.2f%%", 0.0);
				slsmg_printf("%s", hpp->buf);
			}

			percent = 100.0 * period / total;
			ui_browser__set_percent_color(arg->b, percent,
						      arg->current_entry);
			ret += scnprintf(hpp->buf, hpp->size,
					 " %6.2f%%", percent);
			slsmg_printf("%s", hpp->buf);

			prev_idx = perf_evsel__group_idx(evsel);
		}

		idx_delta = nr_members - prev_idx - 1;

		while (idx_delta--) {
			/*
			 * zero-fill group members at last which have no sample
			 */
			ui_browser__set_percent_color(arg->b, 0.0,
						      arg->current_entry);
			ret += scnprintf(hpp->buf, hpp->size,
					 " %6.2f%%", 0.0);
			slsmg_printf("%s", hpp->buf);
		}
	}
out:
	if (!arg->current_entry || !arg->b->navkeypressed)
		ui_browser__set_color(arg->b, HE_COLORSET_NORMAL);

	return ret;
}

#define __HPP_COLOR_PERCENT_FN(_type, _field, _cb)			\
static u64 __hpp_get_##_field(struct hist_entry *he)			\
{									\
	return he->stat._field;						\
}									\
									\
static int								\
hist_browser__hpp_color_##_type(struct perf_hpp_fmt *fmt __maybe_unused,\
				struct perf_hpp *hpp,			\
				struct hist_entry *he)			\
{									\
	return __hpp__color_fmt(hpp, he, __hpp_get_##_field, _cb);	\
}

__HPP_COLOR_PERCENT_FN(overhead, period, __hpp__color_callchain)
__HPP_COLOR_PERCENT_FN(overhead_sys, period_sys, NULL)
__HPP_COLOR_PERCENT_FN(overhead_us, period_us, NULL)
__HPP_COLOR_PERCENT_FN(overhead_guest_sys, period_guest_sys, NULL)
__HPP_COLOR_PERCENT_FN(overhead_guest_us, period_guest_us, NULL)

#undef __HPP_COLOR_PERCENT_FN

void hist_browser__init_hpp(void)
{
	perf_hpp__init();

	perf_hpp__format[PERF_HPP__OVERHEAD].color =
				hist_browser__hpp_color_overhead;
	perf_hpp__format[PERF_HPP__OVERHEAD_SYS].color =
				hist_browser__hpp_color_overhead_sys;
	perf_hpp__format[PERF_HPP__OVERHEAD_US].color =
				hist_browser__hpp_color_overhead_us;
	perf_hpp__format[PERF_HPP__OVERHEAD_GUEST_SYS].color =
				hist_browser__hpp_color_overhead_guest_sys;
	perf_hpp__format[PERF_HPP__OVERHEAD_GUEST_US].color =
				hist_browser__hpp_color_overhead_guest_us;
}

static int hist_browser__show_entry(struct hist_browser *browser,
				    struct hist_entry *entry,
				    unsigned short row)
{
	char s[256];
	int printed = 0;
	int width = browser->b.width;
	char folded_sign = ' ';
	bool current_entry = ui_browser__is_current_entry(&browser->b, row);
	off_t row_offset = entry->row_offset;
	bool first = true;
	struct perf_hpp_fmt *fmt;

	if (current_entry) {
		browser->he_selection = entry;
		browser->selection = &entry->ms;
	}

	if (symbol_conf.use_callchain) {
		hist_entry__init_have_children(entry);
		folded_sign = hist_entry__folded(entry);
	}

	if (row_offset == 0) {
		struct hpp_arg arg = {
			.b 		= &browser->b,
			.folded_sign	= folded_sign,
			.current_entry	= current_entry,
		};
		struct perf_hpp hpp = {
			.buf		= s,
			.size		= sizeof(s),
			.ptr		= &arg,
		};

		ui_browser__gotorc(&browser->b, row, 0);

		perf_hpp__for_each_format(fmt) {
			if (!first) {
				slsmg_printf("  ");
				width -= 2;
			}
			first = false;

			if (fmt->color) {
				width -= fmt->color(fmt, &hpp, entry);
			} else {
				width -= fmt->entry(fmt, &hpp, entry);
				slsmg_printf("%s", s);
			}
		}

		/* The scroll bar isn't being used */
		if (!browser->b.navkeypressed)
			width += 1;

		hist_entry__sort_snprintf(entry, s, sizeof(s), browser->hists);
		slsmg_write_nstring(s, width);
		++row;
		++printed;
	} else
		--row_offset;

	if (folded_sign == '-' && row != browser->b.height) {
		printed += hist_browser__show_callchain(browser, &entry->sorted_chain,
							1, row, &row_offset,
							&current_entry);
		if (current_entry)
			browser->he_selection = entry;
	}

	return printed;
}

static void ui_browser__hists_init_top(struct ui_browser *browser)
{
	if (browser->top == NULL) {
		struct hist_browser *hb;

		hb = container_of(browser, struct hist_browser, b);
		browser->top = rb_first(&hb->hists->entries);
	}
}

static unsigned int hist_browser__refresh(struct ui_browser *browser)
{
	unsigned row = 0;
	struct rb_node *nd;
	struct hist_browser *hb = container_of(browser, struct hist_browser, b);

	ui_browser__hists_init_top(browser);

	for (nd = browser->top; nd; nd = rb_next(nd)) {
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
		float percent = h->stat.period * 100.0 /
					hb->hists->stats.total_period;

		if (h->filtered)
			continue;

		if (percent < hb->min_pcnt)
			continue;

		row += hist_browser__show_entry(hb, h, row);
		if (row == browser->height)
			break;
	}

	return row;
}

static struct rb_node *hists__filter_entries(struct rb_node *nd,
					     struct hists *hists,
					     float min_pcnt)
{
	while (nd != NULL) {
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
		float percent = h->stat.period * 100.0 /
					hists->stats.total_period;

		if (percent < min_pcnt)
			return NULL;

		if (!h->filtered)
			return nd;

		nd = rb_next(nd);
	}

	return NULL;
}

static struct rb_node *hists__filter_prev_entries(struct rb_node *nd,
						  struct hists *hists,
						  float min_pcnt)
{
	while (nd != NULL) {
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
		float percent = h->stat.period * 100.0 /
					hists->stats.total_period;

		if (!h->filtered && percent >= min_pcnt)
			return nd;

		nd = rb_prev(nd);
	}

	return NULL;
}

static void ui_browser__hists_seek(struct ui_browser *browser,
				   off_t offset, int whence)
{
	struct hist_entry *h;
	struct rb_node *nd;
	bool first = true;
	struct hist_browser *hb;

	hb = container_of(browser, struct hist_browser, b);

	if (browser->nr_entries == 0)
		return;

	ui_browser__hists_init_top(browser);

	switch (whence) {
	case SEEK_SET:
		nd = hists__filter_entries(rb_first(browser->entries),
					   hb->hists, hb->min_pcnt);
		break;
	case SEEK_CUR:
		nd = browser->top;
		goto do_offset;
	case SEEK_END:
		nd = hists__filter_prev_entries(rb_last(browser->entries),
						hb->hists, hb->min_pcnt);
		first = false;
		break;
	default:
		return;
	}

	/*
	 * Moves not relative to the first visible entry invalidates its
	 * row_offset:
	 */
	h = rb_entry(browser->top, struct hist_entry, rb_node);
	h->row_offset = 0;

	/*
	 * Here we have to check if nd is expanded (+), if it is we can't go
	 * the next top level hist_entry, instead we must compute an offset of
	 * what _not_ to show and not change the first visible entry.
	 *
	 * This offset increments when we are going from top to bottom and
	 * decreases when we're going from bottom to top.
	 *
	 * As we don't have backpointers to the top level in the callchains
	 * structure, we need to always print the whole hist_entry callchain,
	 * skipping the first ones that are before the first visible entry
	 * and stop when we printed enough lines to fill the screen.
	 */
do_offset:
	if (offset > 0) {
		do {
			h = rb_entry(nd, struct hist_entry, rb_node);
			if (h->ms.unfolded) {
				u16 remaining = h->nr_rows - h->row_offset;
				if (offset > remaining) {
					offset -= remaining;
					h->row_offset = 0;
				} else {
					h->row_offset += offset;
					offset = 0;
					browser->top = nd;
					break;
				}
			}
			nd = hists__filter_entries(rb_next(nd), hb->hists,
						   hb->min_pcnt);
			if (nd == NULL)
				break;
			--offset;
			browser->top = nd;
		} while (offset != 0);
	} else if (offset < 0) {
		while (1) {
			h = rb_entry(nd, struct hist_entry, rb_node);
			if (h->ms.unfolded) {
				if (first) {
					if (-offset > h->row_offset) {
						offset += h->row_offset;
						h->row_offset = 0;
					} else {
						h->row_offset += offset;
						offset = 0;
						browser->top = nd;
						break;
					}
				} else {
					if (-offset > h->nr_rows) {
						offset += h->nr_rows;
						h->row_offset = 0;
					} else {
						h->row_offset = h->nr_rows + offset;
						offset = 0;
						browser->top = nd;
						break;
					}
				}
			}

			nd = hists__filter_prev_entries(rb_prev(nd), hb->hists,
							hb->min_pcnt);
			if (nd == NULL)
				break;
			++offset;
			browser->top = nd;
			if (offset == 0) {
				/*
				 * Last unfiltered hist_entry, check if it is
				 * unfolded, if it is then we should have
				 * row_offset at its last entry.
				 */
				h = rb_entry(nd, struct hist_entry, rb_node);
				if (h->ms.unfolded)
					h->row_offset = h->nr_rows;
				break;
			}
			first = false;
		}
	} else {
		browser->top = nd;
		h = rb_entry(nd, struct hist_entry, rb_node);
		h->row_offset = 0;
	}
}

static int hist_browser__fprintf_callchain_node_rb_tree(struct hist_browser *browser,
							struct callchain_node *chain_node,
							u64 total, int level,
							FILE *fp)
{
	struct rb_node *node;
	int offset = level * LEVEL_OFFSET_STEP;
	u64 new_total, remaining;
	int printed = 0;

	if (callchain_param.mode == CHAIN_GRAPH_REL)
		new_total = chain_node->children_hit;
	else
		new_total = total;

	remaining = new_total;
	node = rb_first(&chain_node->rb_root);
	while (node) {
		struct callchain_node *child = rb_entry(node, struct callchain_node, rb_node);
		struct rb_node *next = rb_next(node);
		u64 cumul = callchain_cumul_hits(child);
		struct callchain_list *chain;
		char folded_sign = ' ';
		int first = true;
		int extra_offset = 0;

		remaining -= cumul;

		list_for_each_entry(chain, &child->val, list) {
			char bf[1024], *alloc_str;
			const char *str;
			bool was_first = first;

			if (first)
				first = false;
			else
				extra_offset = LEVEL_OFFSET_STEP;

			folded_sign = callchain_list__folded(chain);

			alloc_str = NULL;
			str = callchain_list__sym_name(chain, bf, sizeof(bf),
						       browser->show_dso);
			if (was_first) {
				double percent = cumul * 100.0 / new_total;

				if (asprintf(&alloc_str, "%2.2f%% %s", percent, str) < 0)
					str = "Not enough memory!";
				else
					str = alloc_str;
			}

			printed += fprintf(fp, "%*s%c %s\n", offset + extra_offset, " ", folded_sign, str);
			free(alloc_str);
			if (folded_sign == '+')
				break;
		}

		if (folded_sign == '-') {
			const int new_level = level + (extra_offset ? 2 : 1);
			printed += hist_browser__fprintf_callchain_node_rb_tree(browser, child, new_total,
										new_level, fp);
		}

		node = next;
	}

	return printed;
}

static int hist_browser__fprintf_callchain_node(struct hist_browser *browser,
						struct callchain_node *node,
						int level, FILE *fp)
{
	struct callchain_list *chain;
	int offset = level * LEVEL_OFFSET_STEP;
	char folded_sign = ' ';
	int printed = 0;

	list_for_each_entry(chain, &node->val, list) {
		char bf[1024], *s;

		folded_sign = callchain_list__folded(chain);
		s = callchain_list__sym_name(chain, bf, sizeof(bf), browser->show_dso);
		printed += fprintf(fp, "%*s%c %s\n", offset, " ", folded_sign, s);
	}

	if (folded_sign == '-')
		printed += hist_browser__fprintf_callchain_node_rb_tree(browser, node,
									browser->hists->stats.total_period,
									level + 1,  fp);
	return printed;
}

static int hist_browser__fprintf_callchain(struct hist_browser *browser,
					   struct rb_root *chain, int level, FILE *fp)
{
	struct rb_node *nd;
	int printed = 0;

	for (nd = rb_first(chain); nd; nd = rb_next(nd)) {
		struct callchain_node *node = rb_entry(nd, struct callchain_node, rb_node);

		printed += hist_browser__fprintf_callchain_node(browser, node, level, fp);
	}

	return printed;
}

static int hist_browser__fprintf_entry(struct hist_browser *browser,
				       struct hist_entry *he, FILE *fp)
{
	char s[8192];
	double percent;
	int printed = 0;
	char folded_sign = ' ';

	if (symbol_conf.use_callchain)
		folded_sign = hist_entry__folded(he);

	hist_entry__sort_snprintf(he, s, sizeof(s), browser->hists);
	percent = (he->stat.period * 100.0) / browser->hists->stats.total_period;

	if (symbol_conf.use_callchain)
		printed += fprintf(fp, "%c ", folded_sign);

	printed += fprintf(fp, " %5.2f%%", percent);

	if (symbol_conf.show_nr_samples)
		printed += fprintf(fp, " %11u", he->stat.nr_events);

	if (symbol_conf.show_total_period)
		printed += fprintf(fp, " %12" PRIu64, he->stat.period);

	printed += fprintf(fp, "%s\n", rtrim(s));

	if (folded_sign == '-')
		printed += hist_browser__fprintf_callchain(browser, &he->sorted_chain, 1, fp);

	return printed;
}

static int hist_browser__fprintf(struct hist_browser *browser, FILE *fp)
{
	struct rb_node *nd = hists__filter_entries(rb_first(browser->b.entries),
						   browser->hists,
						   browser->min_pcnt);
	int printed = 0;

	while (nd) {
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);

		printed += hist_browser__fprintf_entry(browser, h, fp);
		nd = hists__filter_entries(rb_next(nd), browser->hists,
					   browser->min_pcnt);
	}

	return printed;
}

static int hist_browser__dump(struct hist_browser *browser)
{
	char filename[64];
	FILE *fp;

	while (1) {
		scnprintf(filename, sizeof(filename), "perf.hist.%d", browser->print_seq);
		if (access(filename, F_OK))
			break;
		/*
 		 * XXX: Just an arbitrary lazy upper limit
 		 */
		if (++browser->print_seq == 8192) {
			ui_helpline__fpush("Too many perf.hist.N files, nothing written!");
			return -1;
		}
	}

	fp = fopen(filename, "w");
	if (fp == NULL) {
		char bf[64];
		const char *err = strerror_r(errno, bf, sizeof(bf));
		ui_helpline__fpush("Couldn't write to %s: %s", filename, err);
		return -1;
	}

	++browser->print_seq;
	hist_browser__fprintf(browser, fp);
	fclose(fp);
	ui_helpline__fpush("%s written!", filename);

	return 0;
}

static struct hist_browser *hist_browser__new(struct hists *hists)
{
	struct hist_browser *browser = zalloc(sizeof(*browser));

	if (browser) {
		browser->hists = hists;
		browser->b.refresh = hist_browser__refresh;
		browser->b.seek = ui_browser__hists_seek;
		browser->b.use_navkeypressed = true;
	}

	return browser;
}

static void hist_browser__delete(struct hist_browser *browser)
{
	free(browser);
}

static struct hist_entry *hist_browser__selected_entry(struct hist_browser *browser)
{
	return browser->he_selection;
}

static struct thread *hist_browser__selected_thread(struct hist_browser *browser)
{
	return browser->he_selection->thread;
}

static int hists__browser_title(struct hists *hists, char *bf, size_t size,
				const char *ev_name)
{
	char unit;
	int printed;
	const struct dso *dso = hists->dso_filter;
	const struct thread *thread = hists->thread_filter;
	unsigned long nr_samples = hists->stats.nr_events[PERF_RECORD_SAMPLE];
	u64 nr_events = hists->stats.total_period;
	struct perf_evsel *evsel = hists_to_evsel(hists);
	char buf[512];
	size_t buflen = sizeof(buf);

	if (perf_evsel__is_group_event(evsel)) {
		struct perf_evsel *pos;

		perf_evsel__group_desc(evsel, buf, buflen);
		ev_name = buf;

		for_each_group_member(pos, evsel) {
			nr_samples += pos->hists.stats.nr_events[PERF_RECORD_SAMPLE];
			nr_events += pos->hists.stats.total_period;
		}
	}

	nr_samples = convert_unit(nr_samples, &unit);
	printed = scnprintf(bf, size,
			   "Samples: %lu%c of event '%s', Event count (approx.): %lu",
			   nr_samples, unit, ev_name, nr_events);


	if (hists->uid_filter_str)
		printed += snprintf(bf + printed, size - printed,
				    ", UID: %s", hists->uid_filter_str);
	if (thread)
		printed += scnprintf(bf + printed, size - printed,
				    ", Thread: %s(%d)",
				     (thread->comm_set ? thread__comm_str(thread) : ""),
				    thread->tid);
	if (dso)
		printed += scnprintf(bf + printed, size - printed,
				    ", DSO: %s", dso->short_name);
	return printed;
}

static inline void free_popup_options(char **options, int n)
{
	int i;

	for (i = 0; i < n; ++i) {
		free(options[i]);
		options[i] = NULL;
	}
}

/* Check whether the browser is for 'top' or 'report' */
static inline bool is_report_browser(void *timer)
{
	return timer == NULL;
}

/*
 * Only runtime switching of perf data file will make "input_name" point
 * to a malloced buffer. So add "is_input_name_malloced" flag to decide
 * whether we need to call free() for current "input_name" during the switch.
 */
static bool is_input_name_malloced = false;

static int switch_data_file(void)
{
	char *pwd, *options[32], *abs_path[32], *tmp;
	DIR *pwd_dir;
	int nr_options = 0, choice = -1, ret = -1;
	struct dirent *dent;

	pwd = getenv("PWD");
	if (!pwd)
		return ret;

	pwd_dir = opendir(pwd);
	if (!pwd_dir)
		return ret;

	memset(options, 0, sizeof(options));
	memset(options, 0, sizeof(abs_path));

	while ((dent = readdir(pwd_dir))) {
		char path[PATH_MAX];
		u64 magic;
		char *name = dent->d_name;
		FILE *file;

		if (!(dent->d_type == DT_REG))
			continue;

		snprintf(path, sizeof(path), "%s/%s", pwd, name);

		file = fopen(path, "r");
		if (!file)
			continue;

		if (fread(&magic, 1, 8, file) < 8)
			goto close_file_and_continue;

		if (is_perf_magic(magic)) {
			options[nr_options] = strdup(name);
			if (!options[nr_options])
				goto close_file_and_continue;

			abs_path[nr_options] = strdup(path);
			if (!abs_path[nr_options]) {
				free(options[nr_options]);
				ui__warning("Can't search all data files due to memory shortage.\n");
				fclose(file);
				break;
			}

			nr_options++;
		}

close_file_and_continue:
		fclose(file);
		if (nr_options >= 32) {
			ui__warning("Too many perf data files in PWD!\n"
				    "Only the first 32 files will be listed.\n");
			break;
		}
	}
	closedir(pwd_dir);

	if (nr_options) {
		choice = ui__popup_menu(nr_options, options);
		if (choice < nr_options && choice >= 0) {
			tmp = strdup(abs_path[choice]);
			if (tmp) {
				if (is_input_name_malloced)
					free((void *)input_name);
				input_name = tmp;
				is_input_name_malloced = true;
				ret = 0;
			} else
				ui__warning("Data switch failed due to memory shortage!\n");
		}
	}

	free_popup_options(options, nr_options);
	free_popup_options(abs_path, nr_options);
	return ret;
}

static void hist_browser__update_pcnt_entries(struct hist_browser *hb)
{
	u64 nr_entries = 0;
	struct rb_node *nd = rb_first(&hb->hists->entries);

	while (nd) {
		nr_entries++;
		nd = hists__filter_entries(rb_next(nd), hb->hists,
					   hb->min_pcnt);
	}

	hb->nr_pcnt_entries = nr_entries;
}

static int perf_evsel__hists_browse(struct perf_evsel *evsel, int nr_events,
				    const char *helpline, const char *ev_name,
				    bool left_exits,
				    struct hist_browser_timer *hbt,
				    float min_pcnt,
				    struct perf_session_env *env)
{
	struct hists *hists = &evsel->hists;
	struct hist_browser *browser = hist_browser__new(hists);
	struct branch_info *bi;
	struct pstack *fstack;
	char *options[16];
	int nr_options = 0;
	int key = -1;
	char buf[64];
	char script_opt[64];
	int delay_secs = hbt ? hbt->refresh : 0;

#define HIST_BROWSER_HELP_COMMON					\
	"h/?/F1        Show this window\n"				\
	"UP/DOWN/PGUP\n"						\
	"PGDN/SPACE    Navigate\n"					\
	"q/ESC/CTRL+C  Exit browser\n\n"				\
	"For multiple event sessions:\n\n"				\
	"TAB/UNTAB     Switch events\n\n"				\
	"For symbolic views (--sort has sym):\n\n"			\
	"->            Zoom into DSO/Threads & Annotate current symbol\n" \
	"<-            Zoom out\n"					\
	"a             Annotate current symbol\n"			\
	"C             Collapse all callchains\n"			\
	"d             Zoom into current DSO\n"				\
	"E             Expand all callchains\n"				\

	/* help messages are sorted by lexical order of the hotkey */
	const char report_help[] = HIST_BROWSER_HELP_COMMON
	"P             Print histograms to perf.hist.N\n"
	"r             Run available scripts\n"
	"s             Switch to another data file in PWD\n"
	"t             Zoom into current Thread\n"
	"V             Verbose (DSO names in callchains, etc)\n"
	"/             Filter symbol by name";
	const char top_help[] = HIST_BROWSER_HELP_COMMON
	"P             Print histograms to perf.hist.N\n"
	"t             Zoom into current Thread\n"
	"V             Verbose (DSO names in callchains, etc)\n"
	"/             Filter symbol by name";

	if (browser == NULL)
		return -1;

	if (min_pcnt) {
		browser->min_pcnt = min_pcnt;
		hist_browser__update_pcnt_entries(browser);
	}

	fstack = pstack__new(2);
	if (fstack == NULL)
		goto out;

	ui_helpline__push(helpline);

	memset(options, 0, sizeof(options));

	while (1) {
		const struct thread *thread = NULL;
		const struct dso *dso = NULL;
		int choice = 0,
		    annotate = -2, zoom_dso = -2, zoom_thread = -2,
		    annotate_f = -2, annotate_t = -2, browse_map = -2;
		int scripts_comm = -2, scripts_symbol = -2,
		    scripts_all = -2, switch_data = -2;

		nr_options = 0;

		key = hist_browser__run(browser, ev_name, hbt);

		if (browser->he_selection != NULL) {
			thread = hist_browser__selected_thread(browser);
			dso = browser->selection->map ? browser->selection->map->dso : NULL;
		}
		switch (key) {
		case K_TAB:
		case K_UNTAB:
			if (nr_events == 1)
				continue;
			/*
			 * Exit the browser, let hists__browser_tree
			 * go to the next or previous
			 */
			goto out_free_stack;
		case 'a':
			if (!sort__has_sym) {
				ui_browser__warning(&browser->b, delay_secs * 2,
			"Annotation is only available for symbolic views, "
			"include \"sym*\" in --sort to use it.");
				continue;
			}

			if (browser->selection == NULL ||
			    browser->selection->sym == NULL ||
			    browser->selection->map->dso->annotate_warned)
				continue;
			goto do_annotate;
		case 'P':
			hist_browser__dump(browser);
			continue;
		case 'd':
			goto zoom_dso;
		case 'V':
			browser->show_dso = !browser->show_dso;
			continue;
		case 't':
			goto zoom_thread;
		case '/':
			if (ui_browser__input_window("Symbol to show",
					"Please enter the name of symbol you want to see",
					buf, "ENTER: OK, ESC: Cancel",
					delay_secs * 2) == K_ENTER) {
				hists->symbol_filter_str = *buf ? buf : NULL;
				hists__filter_by_symbol(hists);
				hist_browser__reset(browser);
			}
			continue;
		case 'r':
			if (is_report_browser(hbt))
				goto do_scripts;
			continue;
		case 's':
			if (is_report_browser(hbt))
				goto do_data_switch;
			continue;
		case K_F1:
		case 'h':
		case '?':
			ui_browser__help_window(&browser->b,
				is_report_browser(hbt) ? report_help : top_help);
			continue;
		case K_ENTER:
		case K_RIGHT:
			/* menu */
			break;
		case K_LEFT: {
			const void *top;

			if (pstack__empty(fstack)) {
				/*
				 * Go back to the perf_evsel_menu__run or other user
				 */
				if (left_exits)
					goto out_free_stack;
				continue;
			}
			top = pstack__pop(fstack);
			if (top == &browser->hists->dso_filter)
				goto zoom_out_dso;
			if (top == &browser->hists->thread_filter)
				goto zoom_out_thread;
			continue;
		}
		case K_ESC:
			if (!left_exits &&
			    !ui_browser__dialog_yesno(&browser->b,
					       "Do you really want to exit?"))
				continue;
			/* Fall thru */
		case 'q':
		case CTRL('c'):
			goto out_free_stack;
		default:
			continue;
		}

		if (!sort__has_sym)
			goto add_exit_option;

		if (sort__mode == SORT_MODE__BRANCH) {
			bi = browser->he_selection->branch_info;
			if (browser->selection != NULL &&
			    bi &&
			    bi->from.sym != NULL &&
			    !bi->from.map->dso->annotate_warned &&
				asprintf(&options[nr_options], "Annotate %s",
					 bi->from.sym->name) > 0)
				annotate_f = nr_options++;

			if (browser->selection != NULL &&
			    bi &&
			    bi->to.sym != NULL &&
			    !bi->to.map->dso->annotate_warned &&
			    (bi->to.sym != bi->from.sym ||
			     bi->to.map->dso != bi->from.map->dso) &&
				asprintf(&options[nr_options], "Annotate %s",
					 bi->to.sym->name) > 0)
				annotate_t = nr_options++;
		} else {

			if (browser->selection != NULL &&
			    browser->selection->sym != NULL &&
			    !browser->selection->map->dso->annotate_warned &&
				asprintf(&options[nr_options], "Annotate %s",
					 browser->selection->sym->name) > 0)
				annotate = nr_options++;
		}

		if (thread != NULL &&
		    asprintf(&options[nr_options], "Zoom %s %s(%d) thread",
			     (browser->hists->thread_filter ? "out of" : "into"),
			     (thread->comm_set ? thread__comm_str(thread) : ""),
			     thread->tid) > 0)
			zoom_thread = nr_options++;

		if (dso != NULL &&
		    asprintf(&options[nr_options], "Zoom %s %s DSO",
			     (browser->hists->dso_filter ? "out of" : "into"),
			     (dso->kernel ? "the Kernel" : dso->short_name)) > 0)
			zoom_dso = nr_options++;

		if (browser->selection != NULL &&
		    browser->selection->map != NULL &&
		    asprintf(&options[nr_options], "Browse map details") > 0)
			browse_map = nr_options++;

		/* perf script support */
		if (browser->he_selection) {
			struct symbol *sym;

			if (asprintf(&options[nr_options], "Run scripts for samples of thread [%s]",
				     thread__comm_str(browser->he_selection->thread)) > 0)
				scripts_comm = nr_options++;

			sym = browser->he_selection->ms.sym;
			if (sym && sym->namelen &&
				asprintf(&options[nr_options], "Run scripts for samples of symbol [%s]",
						sym->name) > 0)
				scripts_symbol = nr_options++;
		}

		if (asprintf(&options[nr_options], "Run scripts for all samples") > 0)
			scripts_all = nr_options++;

		if (is_report_browser(hbt) && asprintf(&options[nr_options],
				"Switch to another data file in PWD") > 0)
			switch_data = nr_options++;
add_exit_option:
		options[nr_options++] = (char *)"Exit";
retry_popup_menu:
		choice = ui__popup_menu(nr_options, options);

		if (choice == nr_options - 1)
			break;

		if (choice == -1) {
			free_popup_options(options, nr_options - 1);
			continue;
		}

		if (choice == annotate || choice == annotate_t || choice == annotate_f) {
			struct hist_entry *he;
			int err;
do_annotate:
			if (!objdump_path && perf_session_env__lookup_objdump(env))
				continue;

			he = hist_browser__selected_entry(browser);
			if (he == NULL)
				continue;

			/*
			 * we stash the branch_info symbol + map into the
			 * the ms so we don't have to rewrite all the annotation
			 * code to use branch_info.
			 * in branch mode, the ms struct is not used
			 */
			if (choice == annotate_f) {
				he->ms.sym = he->branch_info->from.sym;
				he->ms.map = he->branch_info->from.map;
			}  else if (choice == annotate_t) {
				he->ms.sym = he->branch_info->to.sym;
				he->ms.map = he->branch_info->to.map;
			}

			/*
			 * Don't let this be freed, say, by hists__decay_entry.
			 */
			he->used = true;
			err = hist_entry__tui_annotate(he, evsel, hbt);
			he->used = false;
			/*
			 * offer option to annotate the other branch source or target
			 * (if they exists) when returning from annotate
			 */
			if ((err == 'q' || err == CTRL('c'))
			    && annotate_t != -2 && annotate_f != -2)
				goto retry_popup_menu;

			ui_browser__update_nr_entries(&browser->b, browser->hists->nr_entries);
			if (err)
				ui_browser__handle_resize(&browser->b);

		} else if (choice == browse_map)
			map__browse(browser->selection->map);
		else if (choice == zoom_dso) {
zoom_dso:
			if (browser->hists->dso_filter) {
				pstack__remove(fstack, &browser->hists->dso_filter);
zoom_out_dso:
				ui_helpline__pop();
				browser->hists->dso_filter = NULL;
				sort_dso.elide = false;
			} else {
				if (dso == NULL)
					continue;
				ui_helpline__fpush("To zoom out press <- or -> + \"Zoom out of %s DSO\"",
						   dso->kernel ? "the Kernel" : dso->short_name);
				browser->hists->dso_filter = dso;
				sort_dso.elide = true;
				pstack__push(fstack, &browser->hists->dso_filter);
			}
			hists__filter_by_dso(hists);
			hist_browser__reset(browser);
		} else if (choice == zoom_thread) {
zoom_thread:
			if (browser->hists->thread_filter) {
				pstack__remove(fstack, &browser->hists->thread_filter);
zoom_out_thread:
				ui_helpline__pop();
				browser->hists->thread_filter = NULL;
				sort_thread.elide = false;
			} else {
				ui_helpline__fpush("To zoom out press <- or -> + \"Zoom out of %s(%d) thread\"",
						   thread->comm_set ? thread__comm_str(thread) : "",
						   thread->tid);
				browser->hists->thread_filter = thread;
				sort_thread.elide = true;
				pstack__push(fstack, &browser->hists->thread_filter);
			}
			hists__filter_by_thread(hists);
			hist_browser__reset(browser);
		}
		/* perf scripts support */
		else if (choice == scripts_all || choice == scripts_comm ||
				choice == scripts_symbol) {
do_scripts:
			memset(script_opt, 0, 64);

			if (choice == scripts_comm)
				sprintf(script_opt, " -c %s ", thread__comm_str(browser->he_selection->thread));

			if (choice == scripts_symbol)
				sprintf(script_opt, " -S %s ", browser->he_selection->ms.sym->name);

			script_browse(script_opt);
		}
		/* Switch to another data file */
		else if (choice == switch_data) {
do_data_switch:
			if (!switch_data_file()) {
				key = K_SWITCH_INPUT_DATA;
				break;
			} else
				ui__warning("Won't switch the data files due to\n"
					"no valid data file get selected!\n");
		}
	}
out_free_stack:
	pstack__delete(fstack);
out:
	hist_browser__delete(browser);
	free_popup_options(options, nr_options - 1);
	return key;
}

struct perf_evsel_menu {
	struct ui_browser b;
	struct perf_evsel *selection;
	bool lost_events, lost_events_warned;
	float min_pcnt;
	struct perf_session_env *env;
};

static void perf_evsel_menu__write(struct ui_browser *browser,
				   void *entry, int row)
{
	struct perf_evsel_menu *menu = container_of(browser,
						    struct perf_evsel_menu, b);
	struct perf_evsel *evsel = list_entry(entry, struct perf_evsel, node);
	bool current_entry = ui_browser__is_current_entry(browser, row);
	unsigned long nr_events = evsel->hists.stats.nr_events[PERF_RECORD_SAMPLE];
	const char *ev_name = perf_evsel__name(evsel);
	char bf[256], unit;
	const char *warn = " ";
	size_t printed;

	ui_browser__set_color(browser, current_entry ? HE_COLORSET_SELECTED :
						       HE_COLORSET_NORMAL);

	if (perf_evsel__is_group_event(evsel)) {
		struct perf_evsel *pos;

		ev_name = perf_evsel__group_name(evsel);

		for_each_group_member(pos, evsel) {
			nr_events += pos->hists.stats.nr_events[PERF_RECORD_SAMPLE];
		}
	}

	nr_events = convert_unit(nr_events, &unit);
	printed = scnprintf(bf, sizeof(bf), "%lu%c%s%s", nr_events,
			   unit, unit == ' ' ? "" : " ", ev_name);
	slsmg_printf("%s", bf);

	nr_events = evsel->hists.stats.nr_events[PERF_RECORD_LOST];
	if (nr_events != 0) {
		menu->lost_events = true;
		if (!current_entry)
			ui_browser__set_color(browser, HE_COLORSET_TOP);
		nr_events = convert_unit(nr_events, &unit);
		printed += scnprintf(bf, sizeof(bf), ": %ld%c%schunks LOST!",
				     nr_events, unit, unit == ' ' ? "" : " ");
		warn = bf;
	}

	slsmg_write_nstring(warn, browser->width - printed);

	if (current_entry)
		menu->selection = evsel;
}

static int perf_evsel_menu__run(struct perf_evsel_menu *menu,
				int nr_events, const char *help,
				struct hist_browser_timer *hbt)
{
	struct perf_evlist *evlist = menu->b.priv;
	struct perf_evsel *pos;
	const char *ev_name, *title = "Available samples";
	int delay_secs = hbt ? hbt->refresh : 0;
	int key;

	if (ui_browser__show(&menu->b, title,
			     "ESC: exit, ENTER|->: Browse histograms") < 0)
		return -1;

	while (1) {
		key = ui_browser__run(&menu->b, delay_secs);

		switch (key) {
		case K_TIMER:
			hbt->timer(hbt->arg);

			if (!menu->lost_events_warned && menu->lost_events) {
				ui_browser__warn_lost_events(&menu->b);
				menu->lost_events_warned = true;
			}
			continue;
		case K_RIGHT:
		case K_ENTER:
			if (!menu->selection)
				continue;
			pos = menu->selection;
browse_hists:
			perf_evlist__set_selected(evlist, pos);
			/*
			 * Give the calling tool a chance to populate the non
			 * default evsel resorted hists tree.
			 */
			if (hbt)
				hbt->timer(hbt->arg);
			ev_name = perf_evsel__name(pos);
			key = perf_evsel__hists_browse(pos, nr_events, help,
						       ev_name, true, hbt,
						       menu->min_pcnt,
						       menu->env);
			ui_browser__show_title(&menu->b, title);
			switch (key) {
			case K_TAB:
				if (pos->node.next == &evlist->entries)
					pos = perf_evlist__first(evlist);
				else
					pos = perf_evsel__next(pos);
				goto browse_hists;
			case K_UNTAB:
				if (pos->node.prev == &evlist->entries)
					pos = perf_evlist__last(evlist);
				else
					pos = perf_evsel__prev(pos);
				goto browse_hists;
			case K_ESC:
				if (!ui_browser__dialog_yesno(&menu->b,
						"Do you really want to exit?"))
					continue;
				/* Fall thru */
			case K_SWITCH_INPUT_DATA:
			case 'q':
			case CTRL('c'):
				goto out;
			default:
				continue;
			}
		case K_LEFT:
			continue;
		case K_ESC:
			if (!ui_browser__dialog_yesno(&menu->b,
					       "Do you really want to exit?"))
				continue;
			/* Fall thru */
		case 'q':
		case CTRL('c'):
			goto out;
		default:
			continue;
		}
	}

out:
	ui_browser__hide(&menu->b);
	return key;
}

static bool filter_group_entries(struct ui_browser *browser __maybe_unused,
				 void *entry)
{
	struct perf_evsel *evsel = list_entry(entry, struct perf_evsel, node);

	if (symbol_conf.event_group && !perf_evsel__is_group_leader(evsel))
		return true;

	return false;
}

static int __perf_evlist__tui_browse_hists(struct perf_evlist *evlist,
					   int nr_entries, const char *help,
					   struct hist_browser_timer *hbt,
					   float min_pcnt,
					   struct perf_session_env *env)
{
	struct perf_evsel *pos;
	struct perf_evsel_menu menu = {
		.b = {
			.entries    = &evlist->entries,
			.refresh    = ui_browser__list_head_refresh,
			.seek	    = ui_browser__list_head_seek,
			.write	    = perf_evsel_menu__write,
			.filter	    = filter_group_entries,
			.nr_entries = nr_entries,
			.priv	    = evlist,
		},
		.min_pcnt = min_pcnt,
		.env = env,
	};

	ui_helpline__push("Press ESC to exit");

	list_for_each_entry(pos, &evlist->entries, node) {
		const char *ev_name = perf_evsel__name(pos);
		size_t line_len = strlen(ev_name) + 7;

		if (menu.b.width < line_len)
			menu.b.width = line_len;
	}

	return perf_evsel_menu__run(&menu, nr_entries, help, hbt);
}

int perf_evlist__tui_browse_hists(struct perf_evlist *evlist, const char *help,
				  struct hist_browser_timer *hbt,
				  float min_pcnt,
				  struct perf_session_env *env)
{
	int nr_entries = evlist->nr_entries;

single_entry:
	if (nr_entries == 1) {
		struct perf_evsel *first = perf_evlist__first(evlist);
		const char *ev_name = perf_evsel__name(first);

		return perf_evsel__hists_browse(first, nr_entries, help,
						ev_name, false, hbt, min_pcnt,
						env);
	}

	if (symbol_conf.event_group) {
		struct perf_evsel *pos;

		nr_entries = 0;
		list_for_each_entry(pos, &evlist->entries, node)
			if (perf_evsel__is_group_leader(pos))
				nr_entries++;

		if (nr_entries == 1)
			goto single_entry;
	}

	return __perf_evlist__tui_browse_hists(evlist, nr_entries, help,
					       hbt, min_pcnt, env);
}