tools/perf/builtin-top.c - kernel/msm-4.9 - Gitiles

 /*
  * builtin-top.c
  *
  * Builtin top command: Display a continuously updated profile of
  * any workload, CPU or specific PID.
  *
  * Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com>
  *
  * Improvements and fixes by:
  *
  *   Arjan van de Ven <arjan@linux.intel.com>
  *   Yanmin Zhang <yanmin.zhang@intel.com>
  *   Wu Fengguang <fengguang.wu@intel.com>
  *   Mike Galbraith <efault@gmx.de>
  *   Paul Mackerras <paulus@samba.org>
  *
  * Released under the GPL v2. (and only v2, not any later version)
  */
 #include "builtin.h"

 #include "perf.h"

 #include "util/symbol.h"
 #include "util/color.h"
 #include "util/util.h"
 #include <linux/rbtree.h>
 #include "util/parse-options.h"
 #include "util/parse-events.h"

 #include <assert.h>
 #include <fcntl.h>

 #include <stdio.h>

 #include <errno.h>
 #include <time.h>
 #include <sched.h>
 #include <pthread.h>

 #include <sys/syscall.h>
 #include <sys/ioctl.h>
 #include <sys/poll.h>
 #include <sys/prctl.h>
 #include <sys/wait.h>
 #include <sys/uio.h>
 #include <sys/mman.h>

 #include <linux/unistd.h>
 #include <linux/types.h>

 static int			fd[MAX_NR_CPUS][MAX_COUNTERS];

 static int			system_wide			=  0;

 static int			default_interval		= 100000;

 static u64			count_filter			=  5;
 static int			print_entries			= 15;

 static int			target_pid			= -1;
 static int			inherit				=  0;
 static int			profile_cpu			= -1;
 static int			nr_cpus				=  0;
 static unsigned int		realtime_prio			=  0;
 static int			group				=  0;
 static unsigned int		page_size;
 static unsigned int		mmap_pages			= 16;
 static int			freq				=  0;
 static int			verbose				=  0;
 static char			*vmlinux			=  NULL;

 static char			*sym_filter;
 static unsigned long		filter_start;
 static unsigned long		filter_end;

 static int			delay_secs			=  2;
 static int			zero;
 static int			dump_symtab;

 /*
  * Symbols
  */

 static u64			min_ip;
 static u64			max_ip = -1ll;

 struct sym_entry {
 	struct rb_node		rb_node;
 	struct list_head	node;
 	unsigned long		count[MAX_COUNTERS];
 	unsigned long		snap_count;
 	double			weight;
 	int			skip;
 };

 struct sym_entry		*sym_filter_entry;

 struct dso			*kernel_dso;

 /*
  * Symbols will be added here in record_ip and will get out
  * after decayed.
  */
 static LIST_HEAD(active_symbols);
 static pthread_mutex_t active_symbols_lock = PTHREAD_MUTEX_INITIALIZER;

 /*
  * Ordering weight: count-1 * count-2 * ... / count-n
  */
 static double sym_weight(const struct sym_entry *sym)
 {
 	double weight = sym->snap_count;
 	int counter;

 	for (counter = 1; counter < nr_counters-1; counter++)
 		weight *= sym->count[counter];

 	weight /= (sym->count[counter] + 1);

 	return weight;
 }

 static long			samples;
 static long			userspace_samples;
 static const char		CONSOLE_CLEAR[] = "[H[2J";

 static void __list_insert_active_sym(struct sym_entry *syme)
 {
 	list_add(&syme->node, &active_symbols);
 }

 static void list_remove_active_sym(struct sym_entry *syme)
 {
 	pthread_mutex_lock(&active_symbols_lock);
 	list_del_init(&syme->node);
 	pthread_mutex_unlock(&active_symbols_lock);
 }

 static void rb_insert_active_sym(struct rb_root *tree, struct sym_entry *se)
 {
 	struct rb_node **p = &tree->rb_node;
 	struct rb_node *parent = NULL;
 	struct sym_entry *iter;

 	while (*p != NULL) {
 		parent = *p;
 		iter = rb_entry(parent, struct sym_entry, rb_node);

 		if (se->weight > iter->weight)
 			p = &(*p)->rb_left;
 		else
 			p = &(*p)->rb_right;
 	}

 	rb_link_node(&se->rb_node, parent, p);
 	rb_insert_color(&se->rb_node, tree);
 }

 static void print_sym_table(void)
 {
 	int printed = 0, j;
 	int counter;
 	float samples_per_sec = samples/delay_secs;
 	float ksamples_per_sec = (samples-userspace_samples)/delay_secs;
 	float sum_ksamples = 0.0;
 	struct sym_entry *syme, *n;
 	struct rb_root tmp = RB_ROOT;
 	struct rb_node *nd;

 	samples = userspace_samples = 0;

 	/* Sort the active symbols */
 	pthread_mutex_lock(&active_symbols_lock);
 	syme = list_entry(active_symbols.next, struct sym_entry, node);
 	pthread_mutex_unlock(&active_symbols_lock);

 	list_for_each_entry_safe_from(syme, n, &active_symbols, node) {
 		syme->snap_count = syme->count[0];
 		if (syme->snap_count != 0) {
 			syme->weight = sym_weight(syme);
 			rb_insert_active_sym(&tmp, syme);
 			sum_ksamples += syme->snap_count;

 			for (j = 0; j < nr_counters; j++)
 				syme->count[j] = zero ? 0 : syme->count[j] * 7 / 8;
 		} else
 			list_remove_active_sym(syme);
 	}

 	puts(CONSOLE_CLEAR);

 	printf(
 "------------------------------------------------------------------------------\n");
 	printf( "   PerfTop:%8.0f irqs/sec  kernel:%4.1f%% [",
 		samples_per_sec,
 		100.0 - (100.0*((samples_per_sec-ksamples_per_sec)/samples_per_sec)));

 	if (nr_counters == 1) {
 		printf("%Ld", (u64)attrs[0].sample_period);
 		if (freq)
 			printf("Hz ");
 		else
 			printf(" ");
 	}

 	for (counter = 0; counter < nr_counters; counter++) {
 		if (counter)
 			printf("/");

 		printf("%s", event_name(counter));
 	}

 	printf( "], ");

 	if (target_pid != -1)
 		printf(" (target_pid: %d", target_pid);
 	else
 		printf(" (all");

 	if (profile_cpu != -1)
 		printf(", cpu: %d)\n", profile_cpu);
 	else {
 		if (target_pid != -1)
 			printf(")\n");
 		else
 			printf(", %d CPUs)\n", nr_cpus);
 	}

 	printf("------------------------------------------------------------------------------\n\n");

 	if (nr_counters == 1)
 		printf("             samples    pcnt");
 	else
 		printf("  weight     samples    pcnt");

 	printf("         RIP          kernel function\n"
 	       	       "  ______     _______   _____   ________________   _______________\n\n"
 	);

 	for (nd = rb_first(&tmp); nd; nd = rb_next(nd)) {
 		struct sym_entry *syme = rb_entry(nd, struct sym_entry, rb_node);
 		struct symbol *sym = (struct symbol *)(syme + 1);
 		double pcnt;

 		if (++printed > print_entries || syme->snap_count < count_filter)
 			continue;

 		pcnt = 100.0 - (100.0 * ((sum_ksamples - syme->snap_count) /
 					 sum_ksamples));

 		if (nr_counters == 1)
 			printf("%20.2f - ", syme->weight);
 		else
 			printf("%9.1f %10ld - ", syme->weight, syme->snap_count);

 		percent_color_fprintf(stdout, "%4.1f%%", pcnt);
 		printf(" - %016llx : %s", sym->start, sym->name);
 		if (sym->module)
 			printf("\t[%s]", sym->module->name);
 		printf("\n");
 	}
 }

 static void *display_thread(void *arg __used)
 {
 	struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
 	int delay_msecs = delay_secs * 1000;

 	printf("PerfTop refresh period: %d seconds\n", delay_secs);

 	do {
 		print_sym_table();
 	} while (!poll(&stdin_poll, 1, delay_msecs) == 1);

 	printf("key pressed - exiting.\n");
 	exit(0);

 	return NULL;
 }

 /* Tag samples to be skipped. */
 static const char *skip_symbols[] = {
 	"default_idle",
 	"cpu_idle",
 	"enter_idle",
 	"exit_idle",
 	"mwait_idle",
 	"ppc64_runlatch_off",
 	"pseries_dedicated_idle_sleep",
 	NULL
 };

 static int symbol_filter(struct dso *self, struct symbol *sym)
 {
 	static int filter_match;
 	struct sym_entry *syme;
 	const char *name = sym->name;
 	int i;

 	/*
 	 * ppc64 uses function descriptors and appends a '.' to the
 	 * start of every instruction address. Remove it.
 	 */
 	if (name[0] == '.')
 		name++;

 	if (!strcmp(name, "_text") ||
 	    !strcmp(name, "_etext") ||
 	    !strcmp(name, "_sinittext") ||
 	    !strncmp("init_module", name, 11) ||
 	    !strncmp("cleanup_module", name, 14) ||
 	    strstr(name, "_text_start") ||
 	    strstr(name, "_text_end"))
 		return 1;

 	syme = dso__sym_priv(self, sym);
 	for (i = 0; skip_symbols[i]; i++) {
 		if (!strcmp(skip_symbols[i], name)) {
 			syme->skip = 1;
 			break;
 		}
 	}

 	if (filter_match == 1) {
 		filter_end = sym->start;
 		filter_match = -1;
 		if (filter_end - filter_start > 10000) {
 			fprintf(stderr,
 				"hm, too large filter symbol <%s> - skipping.\n",
 				sym_filter);
 			fprintf(stderr, "symbol filter start: %016lx\n",
 				filter_start);
 			fprintf(stderr, "                end: %016lx\n",
 				filter_end);
 			filter_end = filter_start = 0;
 			sym_filter = NULL;
 			sleep(1);
 		}
 	}

 	if (filter_match == 0 && sym_filter && !strcmp(name, sym_filter)) {
 		filter_match = 1;
 		filter_start = sym->start;
 	}


 	return 0;
 }

 static int parse_symbols(void)
 {
 	struct rb_node *node;
 	struct symbol  *sym;
 	int modules = vmlinux ? 1 : 0;

 	kernel_dso = dso__new("[kernel]", sizeof(struct sym_entry));
 	if (kernel_dso == NULL)
 		return -1;

 	if (dso__load_kernel(kernel_dso, vmlinux, symbol_filter, verbose, modules) <= 0)
 		goto out_delete_dso;

 	node = rb_first(&kernel_dso->syms);
 	sym = rb_entry(node, struct symbol, rb_node);
 	min_ip = sym->start;

 	node = rb_last(&kernel_dso->syms);
 	sym = rb_entry(node, struct symbol, rb_node);
 	max_ip = sym->end;

 	if (dump_symtab)
 		dso__fprintf(kernel_dso, stderr);

 	return 0;

 out_delete_dso:
 	dso__delete(kernel_dso);
 	kernel_dso = NULL;
 	return -1;
 }

 #define TRACE_COUNT     3

 /*
  * Binary search in the histogram table and record the hit:
  */
 static void record_ip(u64 ip, int counter)
 {
 	struct symbol *sym = dso__find_symbol(kernel_dso, ip);

 	if (sym != NULL) {
 		struct sym_entry *syme = dso__sym_priv(kernel_dso, sym);

 		if (!syme->skip) {
 			syme->count[counter]++;
 			pthread_mutex_lock(&active_symbols_lock);
 			if (list_empty(&syme->node) || !syme->node.next)
 				__list_insert_active_sym(syme);
 			pthread_mutex_unlock(&active_symbols_lock);
 			return;
 		}
 	}

 	samples--;
 }

 static void process_event(u64 ip, int counter, int user)
 {
 	samples++;

 	if (user) {
 		userspace_samples++;
 		return;
 	}

 	record_ip(ip, counter);
 }

 struct mmap_data {
 	int			counter;
 	void			*base;
 	int			mask;
 	unsigned int		prev;
 };

 static unsigned int mmap_read_head(struct mmap_data *md)
 {
 	struct perf_counter_mmap_page *pc = md->base;
 	int head;

 	head = pc->data_head;
 	rmb();

 	return head;
 }

 struct timeval last_read, this_read;

 static void mmap_read_counter(struct mmap_data *md)
 {
 	unsigned int head = mmap_read_head(md);
 	unsigned int old = md->prev;
 	unsigned char *data = md->base + page_size;
 	int diff;

 	gettimeofday(&this_read, NULL);

 	/*
 	 * If we're further behind than half the buffer, there's a chance
 	 * the writer will bite our tail and mess up the samples under us.
 	 *
 	 * If we somehow ended up ahead of the head, we got messed up.
 	 *
 	 * In either case, truncate and restart at head.
 	 */
 	diff = head - old;
 	if (diff > md->mask / 2 || diff < 0) {
 		struct timeval iv;
 		unsigned long msecs;

 		timersub(&this_read, &last_read, &iv);
 		msecs = iv.tv_sec*1000 + iv.tv_usec/1000;

 		fprintf(stderr, "WARNING: failed to keep up with mmap data."
 				"  Last read %lu msecs ago.\n", msecs);

 		/*
 		 * head points to a known good entry, start there.
 		 */
 		old = head;
 	}

 	last_read = this_read;

 	for (; old != head;) {
 		struct ip_event {
 			struct perf_event_header header;
 			u64 ip;
 			u32 pid, target_pid;
 		};
 		struct mmap_event {
 			struct perf_event_header header;
 			u32 pid, target_pid;
 			u64 start;
 			u64 len;
 			u64 pgoff;
 			char filename[PATH_MAX];
 		};

 		typedef union event_union {
 			struct perf_event_header header;
 			struct ip_event ip;
 			struct mmap_event mmap;
 		} event_t;

 		event_t *event = (event_t *)&data[old & md->mask];

 		event_t event_copy;

 		size_t size = event->header.size;

 		/*
 		 * Event straddles the mmap boundary -- header should always
 		 * be inside due to u64 alignment of output.
 		 */
 		if ((old & md->mask) + size != ((old + size) & md->mask)) {
 			unsigned int offset = old;
 			unsigned int len = min(sizeof(*event), size), cpy;
 			void *dst = &event_copy;

 			do {
 				cpy = min(md->mask + 1 - (offset & md->mask), len);
 				memcpy(dst, &data[offset & md->mask], cpy);
 				offset += cpy;
 				dst += cpy;
 				len -= cpy;
 			} while (len);

 			event = &event_copy;
 		}

 		old += size;

 		if (event->header.type == PERF_EVENT_SAMPLE) {
 			int user =
 	(event->header.misc & PERF_EVENT_MISC_CPUMODE_MASK) == PERF_EVENT_MISC_USER;
 			process_event(event->ip.ip, md->counter, user);
 		}
 	}

 	md->prev = old;
 }

 static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
 static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];

 static void mmap_read(void)
 {
 	int i, counter;

 	for (i = 0; i < nr_cpus; i++) {
 		for (counter = 0; counter < nr_counters; counter++)
 			mmap_read_counter(&mmap_array[i][counter]);
 	}
 }

 int nr_poll;
 int group_fd;

 static void start_counter(int i, int counter)
 {
 	struct perf_counter_attr *attr;
 	int cpu;

 	cpu = profile_cpu;
 	if (target_pid == -1 && profile_cpu == -1)
 		cpu = i;

 	attr = attrs + counter;

 	attr->sample_type	= PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 	attr->freq		= freq;
 	attr->inherit		= (cpu < 0) && inherit;

 try_again:
 	fd[i][counter] = sys_perf_counter_open(attr, target_pid, cpu, group_fd, 0);

 	if (fd[i][counter] < 0) {
 		int err = errno;

 		if (err == EPERM)
 			die("No permission - are you root?\n");
 		/*
 		 * If it's cycles then fall back to hrtimer
 		 * based cpu-clock-tick sw counter, which
 		 * is always available even if no PMU support:
 		 */
 		if (attr->type == PERF_TYPE_HARDWARE
 			&& attr->config == PERF_COUNT_HW_CPU_CYCLES) {

 			if (verbose)
 				warning(" ... trying to fall back to cpu-clock-ticks\n");

 			attr->type = PERF_TYPE_SOFTWARE;
 			attr->config = PERF_COUNT_SW_CPU_CLOCK;
 			goto try_again;
 		}
 		printf("\n");
 		error("perfcounter syscall returned with %d (%s)\n",
 			fd[i][counter], strerror(err));
 		die("No CONFIG_PERF_COUNTERS=y kernel support configured?\n");
 		exit(-1);
 	}
 	assert(fd[i][counter] >= 0);
 	fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);

 	/*
 	 * First counter acts as the group leader:
 	 */
 	if (group && group_fd == -1)
 		group_fd = fd[i][counter];

 	event_array[nr_poll].fd = fd[i][counter];
 	event_array[nr_poll].events = POLLIN;
 	nr_poll++;

 	mmap_array[i][counter].counter = counter;
 	mmap_array[i][counter].prev = 0;
 	mmap_array[i][counter].mask = mmap_pages*page_size - 1;
 	mmap_array[i][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 			PROT_READ, MAP_SHARED, fd[i][counter], 0);
 	if (mmap_array[i][counter].base == MAP_FAILED)
 		die("failed to mmap with %d (%s)\n", errno, strerror(errno));
 }

 static int __cmd_top(void)
 {
 	pthread_t thread;
 	int i, counter;
 	int ret;

 	for (i = 0; i < nr_cpus; i++) {
 		group_fd = -1;
 		for (counter = 0; counter < nr_counters; counter++)
 			start_counter(i, counter);
 	}

 	/* Wait for a minimal set of events before starting the snapshot */
 	poll(event_array, nr_poll, 100);

 	mmap_read();

 	if (pthread_create(&thread, NULL, display_thread, NULL)) {
 		printf("Could not create display thread.\n");
 		exit(-1);
 	}

 	if (realtime_prio) {
 		struct sched_param param;

 		param.sched_priority = realtime_prio;
 		if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 			printf("Could not set realtime priority.\n");
 			exit(-1);
 		}
 	}

 	while (1) {
 		int hits = samples;

 		mmap_read();

 		if (hits == samples)
 			ret = poll(event_array, nr_poll, 100);
 	}

 	return 0;
 }

 static const char * const top_usage[] = {
 	"perf top [<options>]",
 	NULL
 };

 static const struct option options[] = {
 	OPT_CALLBACK('e', "event", NULL, "event",
 		     "event selector. use 'perf list' to list available events",
 		     parse_events),
 	OPT_INTEGER('c', "count", &default_interval,
 		    "event period to sample"),
 	OPT_INTEGER('p', "pid", &target_pid,
 		    "profile events on existing pid"),
 	OPT_BOOLEAN('a', "all-cpus", &system_wide,
 			    "system-wide collection from all CPUs"),
 	OPT_INTEGER('C', "CPU", &profile_cpu,
 		    "CPU to profile on"),
 	OPT_STRING('k', "vmlinux", &vmlinux, "file", "vmlinux pathname"),
 	OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 		    "number of mmap data pages"),
 	OPT_INTEGER('r', "realtime", &realtime_prio,
 		    "collect data with this RT SCHED_FIFO priority"),
 	OPT_INTEGER('d', "delay", &delay_secs,
 		    "number of seconds to delay between refreshes"),
 	OPT_BOOLEAN('D', "dump-symtab", &dump_symtab,
 			    "dump the symbol table used for profiling"),
 	OPT_INTEGER('f', "count-filter", &count_filter,
 		    "only display functions with more events than this"),
 	OPT_BOOLEAN('g', "group", &group,
 			    "put the counters into a counter group"),
 	OPT_BOOLEAN('i', "inherit", &inherit,
 		    "child tasks inherit counters"),
 	OPT_STRING('s', "sym-filter", &sym_filter, "pattern",
 		    "only display symbols matchig this pattern"),
 	OPT_BOOLEAN('z', "zero", &zero,
 		    "zero history across updates"),
 	OPT_INTEGER('F', "freq", &freq,
 		    "profile at this frequency"),
 	OPT_INTEGER('E', "entries", &print_entries,
 		    "display this many functions"),
 	OPT_BOOLEAN('v', "verbose", &verbose,
 		    "be more verbose (show counter open errors, etc)"),
 	OPT_END()
 };

 int cmd_top(int argc, const char **argv, const char *prefix __used)
 {
 	int counter;

 	symbol__init();

 	page_size = sysconf(_SC_PAGE_SIZE);

 	argc = parse_options(argc, argv, options, top_usage, 0);
 	if (argc)
 		usage_with_options(top_usage, options);

 	if (freq) {
 		default_interval = freq;
 		freq = 1;
 	}

 	/* CPU and PID are mutually exclusive */
 	if (target_pid != -1 && profile_cpu != -1) {
 		printf("WARNING: PID switch overriding CPU\n");
 		sleep(1);
 		profile_cpu = -1;
 	}

 	if (!nr_counters)
 		nr_counters = 1;

 	if (delay_secs < 1)
 		delay_secs = 1;

 	parse_symbols();

 	/*
 	 * Fill in the ones not specifically initialized via -c:
 	 */
 	for (counter = 0; counter < nr_counters; counter++) {
 		if (attrs[counter].sample_period)
 			continue;

 		attrs[counter].sample_period = default_interval;
 	}

 	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 	assert(nr_cpus <= MAX_NR_CPUS);
 	assert(nr_cpus >= 0);

 	if (target_pid != -1 || profile_cpu != -1)
 		nr_cpus = 1;

 	return __cmd_top();
 }
	/*
	* builtin-top.c
	*
	* Builtin top command: Display a continuously updated profile of
	* any workload, CPU or specific PID.
	*
	* Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com>
	*
	* Improvements and fixes by:
	*
	* Arjan van de Ven <arjan@linux.intel.com>
	* Yanmin Zhang <yanmin.zhang@intel.com>
	* Wu Fengguang <fengguang.wu@intel.com>
	* Mike Galbraith <efault@gmx.de>
	* Paul Mackerras <paulus@samba.org>
	*
	* Released under the GPL v2. (and only v2, not any later version)
	*/
	#include "builtin.h"

	#include "perf.h"

	#include "util/symbol.h"
	#include "util/color.h"
	#include "util/util.h"
	#include <linux/rbtree.h>
	#include "util/parse-options.h"
	#include "util/parse-events.h"

	#include <assert.h>
	#include <fcntl.h>

	#include <stdio.h>

	#include <errno.h>
	#include <time.h>
	#include <sched.h>
	#include <pthread.h>

	#include <sys/syscall.h>
	#include <sys/ioctl.h>
	#include <sys/poll.h>
	#include <sys/prctl.h>
	#include <sys/wait.h>
	#include <sys/uio.h>
	#include <sys/mman.h>

	#include <linux/unistd.h>
	#include <linux/types.h>

	static int fd[MAX_NR_CPUS][MAX_COUNTERS];

	static int system_wide = 0;

	static int default_interval = 100000;

	static u64 count_filter = 5;
	static int print_entries = 15;

	static int target_pid = -1;
	static int inherit = 0;
	static int profile_cpu = -1;
	static int nr_cpus = 0;
	static unsigned int realtime_prio = 0;
	static int group = 0;
	static unsigned int page_size;
	static unsigned int mmap_pages = 16;
	static int freq = 0;
	static int verbose = 0;
	static char *vmlinux = NULL;

	static char *sym_filter;
	static unsigned long filter_start;
	static unsigned long filter_end;

	static int delay_secs = 2;
	static int zero;
	static int dump_symtab;

	/*
	* Symbols
	*/

	static u64 min_ip;
	static u64 max_ip = -1ll;

	struct sym_entry {
	struct rb_node rb_node;
	struct list_head node;
	unsigned long count[MAX_COUNTERS];
	unsigned long snap_count;
	double weight;
	int skip;
	};

	struct sym_entry *sym_filter_entry;

	struct dso *kernel_dso;

	/*
	* Symbols will be added here in record_ip and will get out
	* after decayed.
	*/
	static LIST_HEAD(active_symbols);
	static pthread_mutex_t active_symbols_lock = PTHREAD_MUTEX_INITIALIZER;

	/*
	* Ordering weight: count-1 * count-2 * ... / count-n
	*/
	static double sym_weight(const struct sym_entry *sym)
	{
	double weight = sym->snap_count;
	int counter;

	for (counter = 1; counter < nr_counters-1; counter++)
	weight *= sym->count[counter];

	weight /= (sym->count[counter] + 1);

	return weight;
	}

	static long samples;
	static long userspace_samples;
	static const char CONSOLE_CLEAR[] = "[H[2J";

	static void __list_insert_active_sym(struct sym_entry *syme)
	{
	list_add(&syme->node, &active_symbols);
	}

	static void list_remove_active_sym(struct sym_entry *syme)
	{
	pthread_mutex_lock(&active_symbols_lock);
	list_del_init(&syme->node);
	pthread_mutex_unlock(&active_symbols_lock);
	}

	static void rb_insert_active_sym(struct rb_root tree, struct sym_entry se)
	{
	struct rb_node **p = &tree->rb_node;
	struct rb_node *parent = NULL;
	struct sym_entry *iter;

	while (*p != NULL) {
	parent = *p;
	iter = rb_entry(parent, struct sym_entry, rb_node);

	if (se->weight > iter->weight)
	p = &(*p)->rb_left;
	else
	p = &(*p)->rb_right;
	}

	rb_link_node(&se->rb_node, parent, p);
	rb_insert_color(&se->rb_node, tree);
	}

	static void print_sym_table(void)
	{
	int printed = 0, j;
	int counter;
	float samples_per_sec = samples/delay_secs;
	float ksamples_per_sec = (samples-userspace_samples)/delay_secs;
	float sum_ksamples = 0.0;
	struct sym_entry syme, n;
	struct rb_root tmp = RB_ROOT;
	struct rb_node *nd;

	samples = userspace_samples = 0;

	/* Sort the active symbols */
	pthread_mutex_lock(&active_symbols_lock);
	syme = list_entry(active_symbols.next, struct sym_entry, node);
	pthread_mutex_unlock(&active_symbols_lock);

	list_for_each_entry_safe_from(syme, n, &active_symbols, node) {
	syme->snap_count = syme->count[0];
	if (syme->snap_count != 0) {
	syme->weight = sym_weight(syme);
	rb_insert_active_sym(&tmp, syme);
	sum_ksamples += syme->snap_count;

	for (j = 0; j < nr_counters; j++)
	syme->count[j] = zero ? 0 : syme->count[j] * 7 / 8;
	} else
	list_remove_active_sym(syme);
	}

	puts(CONSOLE_CLEAR);

	printf(
	"------------------------------------------------------------------------------\n");
	printf( " PerfTop:%8.0f irqs/sec kernel:%4.1f%% [",
	samples_per_sec,
	100.0 - (100.0*((samples_per_sec-ksamples_per_sec)/samples_per_sec)));

	if (nr_counters == 1) {
	printf("%Ld", (u64)attrs[0].sample_period);
	if (freq)
	printf("Hz ");
	else
	printf(" ");
	}

	for (counter = 0; counter < nr_counters; counter++) {
	if (counter)
	printf("/");

	printf("%s", event_name(counter));
	}

	printf( "], ");

	if (target_pid != -1)
	printf(" (target_pid: %d", target_pid);
	else
	printf(" (all");

	if (profile_cpu != -1)
	printf(", cpu: %d)\n", profile_cpu);
	else {
	if (target_pid != -1)
	printf(")\n");
	else
	printf(", %d CPUs)\n", nr_cpus);
	}

	printf("------------------------------------------------------------------------------\n\n");

	if (nr_counters == 1)
	printf(" samples pcnt");
	else
	printf(" weight samples pcnt");

	printf(" RIP kernel function\n"
	" ______ _______ _____ ________________ _______________\n\n"
	);

	for (nd = rb_first(&tmp); nd; nd = rb_next(nd)) {
	struct sym_entry *syme = rb_entry(nd, struct sym_entry, rb_node);
	struct symbol sym = (struct symbol )(syme + 1);
	double pcnt;

	if (++printed > print_entries \|\| syme->snap_count < count_filter)
	continue;

	pcnt = 100.0 - (100.0 * ((sum_ksamples - syme->snap_count) /
	sum_ksamples));

	if (nr_counters == 1)
	printf("%20.2f - ", syme->weight);
	else
	printf("%9.1f %10ld - ", syme->weight, syme->snap_count);

	percent_color_fprintf(stdout, "%4.1f%%", pcnt);
	printf(" - %016llx : %s", sym->start, sym->name);
	if (sym->module)
	printf("\t[%s]", sym->module->name);
	printf("\n");
	}
	}

	static void display_thread(void arg __used)
	{
	struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
	int delay_msecs = delay_secs * 1000;

	printf("PerfTop refresh period: %d seconds\n", delay_secs);

	do {
	print_sym_table();
	} while (!poll(&stdin_poll, 1, delay_msecs) == 1);

	printf("key pressed - exiting.\n");
	exit(0);

	return NULL;
	}

	/* Tag samples to be skipped. */
	static const char *skip_symbols[] = {
	"default_idle",
	"cpu_idle",
	"enter_idle",
	"exit_idle",
	"mwait_idle",
	"ppc64_runlatch_off",
	"pseries_dedicated_idle_sleep",
	NULL
	};

	static int symbol_filter(struct dso self, struct symbol sym)
	{
	static int filter_match;
	struct sym_entry *syme;
	const char *name = sym->name;
	int i;

	/*
	* ppc64 uses function descriptors and appends a '.' to the
	* start of every instruction address. Remove it.
	*/
	if (name[0] == '.')
	name++;

	if (!strcmp(name, "_text") \|\|
	!strcmp(name, "_etext") \|\|
	!strcmp(name, "_sinittext") \|\|
	!strncmp("init_module", name, 11) \|\|
	!strncmp("cleanup_module", name, 14) \|\|
	strstr(name, "_text_start") \|\|
	strstr(name, "_text_end"))
	return 1;

	syme = dso__sym_priv(self, sym);
	for (i = 0; skip_symbols[i]; i++) {
	if (!strcmp(skip_symbols[i], name)) {
	syme->skip = 1;
	break;
	}
	}

	if (filter_match == 1) {
	filter_end = sym->start;
	filter_match = -1;
	if (filter_end - filter_start > 10000) {
	fprintf(stderr,
	"hm, too large filter symbol <%s> - skipping.\n",
	sym_filter);
	fprintf(stderr, "symbol filter start: %016lx\n",
	filter_start);
	fprintf(stderr, " end: %016lx\n",
	filter_end);
	filter_end = filter_start = 0;
	sym_filter = NULL;
	sleep(1);
	}
	}

	if (filter_match == 0 && sym_filter && !strcmp(name, sym_filter)) {
	filter_match = 1;
	filter_start = sym->start;
	}


	return 0;
	}

	static int parse_symbols(void)
	{
	struct rb_node *node;
	struct symbol *sym;
	int modules = vmlinux ? 1 : 0;

	kernel_dso = dso__new("[kernel]", sizeof(struct sym_entry));
	if (kernel_dso == NULL)
	return -1;

	if (dso__load_kernel(kernel_dso, vmlinux, symbol_filter, verbose, modules) <= 0)
	goto out_delete_dso;

	node = rb_first(&kernel_dso->syms);
	sym = rb_entry(node, struct symbol, rb_node);
	min_ip = sym->start;

	node = rb_last(&kernel_dso->syms);
	sym = rb_entry(node, struct symbol, rb_node);
	max_ip = sym->end;

	if (dump_symtab)
	dso__fprintf(kernel_dso, stderr);

	return 0;

	out_delete_dso:
	dso__delete(kernel_dso);
	kernel_dso = NULL;
	return -1;
	}

	#define TRACE_COUNT 3

	/*
	* Binary search in the histogram table and record the hit:
	*/
	static void record_ip(u64 ip, int counter)
	{
	struct symbol *sym = dso__find_symbol(kernel_dso, ip);

	if (sym != NULL) {
	struct sym_entry *syme = dso__sym_priv(kernel_dso, sym);

	if (!syme->skip) {
	syme->count[counter]++;
	pthread_mutex_lock(&active_symbols_lock);
	if (list_empty(&syme->node) \|\| !syme->node.next)
	__list_insert_active_sym(syme);
	pthread_mutex_unlock(&active_symbols_lock);
	return;
	}
	}

	samples--;
	}

	static void process_event(u64 ip, int counter, int user)
	{
	samples++;

	if (user) {
	userspace_samples++;
	return;
	}

	record_ip(ip, counter);
	}

	struct mmap_data {
	int counter;
	void *base;
	int mask;
	unsigned int prev;
	};

	static unsigned int mmap_read_head(struct mmap_data *md)
	{
	struct perf_counter_mmap_page *pc = md->base;
	int head;

	head = pc->data_head;
	rmb();

	return head;
	}

	struct timeval last_read, this_read;

	static void mmap_read_counter(struct mmap_data *md)
	{
	unsigned int head = mmap_read_head(md);
	unsigned int old = md->prev;
	unsigned char *data = md->base + page_size;
	int diff;

	gettimeofday(&this_read, NULL);

	/*
	* If we're further behind than half the buffer, there's a chance
	* the writer will bite our tail and mess up the samples under us.
	*
	* If we somehow ended up ahead of the head, we got messed up.
	*
	* In either case, truncate and restart at head.
	*/
	diff = head - old;
	if (diff > md->mask / 2 \|\| diff < 0) {
	struct timeval iv;
	unsigned long msecs;

	timersub(&this_read, &last_read, &iv);
	msecs = iv.tv_sec*1000 + iv.tv_usec/1000;

	fprintf(stderr, "WARNING: failed to keep up with mmap data."
	" Last read %lu msecs ago.\n", msecs);

	/*
	* head points to a known good entry, start there.
	*/
	old = head;
	}

	last_read = this_read;

	for (; old != head;) {
	struct ip_event {
	struct perf_event_header header;
	u64 ip;
	u32 pid, target_pid;
	};
	struct mmap_event {
	struct perf_event_header header;
	u32 pid, target_pid;
	u64 start;
	u64 len;
	u64 pgoff;
	char filename[PATH_MAX];
	};

	typedef union event_union {
	struct perf_event_header header;
	struct ip_event ip;
	struct mmap_event mmap;
	} event_t;

	event_t event = (event_t )&data[old & md->mask];

	event_t event_copy;

	size_t size = event->header.size;

	/*
	* Event straddles the mmap boundary -- header should always
	* be inside due to u64 alignment of output.
	*/
	if ((old & md->mask) + size != ((old + size) & md->mask)) {
	unsigned int offset = old;
	unsigned int len = min(sizeof(*event), size), cpy;
	void *dst = &event_copy;

	do {
	cpy = min(md->mask + 1 - (offset & md->mask), len);
	memcpy(dst, &data[offset & md->mask], cpy);
	offset += cpy;
	dst += cpy;
	len -= cpy;
	} while (len);

	event = &event_copy;
	}

	old += size;

	if (event->header.type == PERF_EVENT_SAMPLE) {
	int user =
	(event->header.misc & PERF_EVENT_MISC_CPUMODE_MASK) == PERF_EVENT_MISC_USER;
	process_event(event->ip.ip, md->counter, user);
	}
	}

	md->prev = old;
	}

	static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
	static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];

	static void mmap_read(void)
	{
	int i, counter;

	for (i = 0; i < nr_cpus; i++) {
	for (counter = 0; counter < nr_counters; counter++)
	mmap_read_counter(&mmap_array[i][counter]);
	}
	}

	int nr_poll;
	int group_fd;

	static void start_counter(int i, int counter)
	{
	struct perf_counter_attr *attr;
	int cpu;

	cpu = profile_cpu;
	if (target_pid == -1 && profile_cpu == -1)
	cpu = i;

	attr = attrs + counter;

	attr->sample_type = PERF_SAMPLE_IP \| PERF_SAMPLE_TID;
	attr->freq = freq;
	attr->inherit = (cpu < 0) && inherit;

	try_again:
	fd[i][counter] = sys_perf_counter_open(attr, target_pid, cpu, group_fd, 0);

	if (fd[i][counter] < 0) {
	int err = errno;

	if (err == EPERM)
	die("No permission - are you root?\n");
	/*
	* If it's cycles then fall back to hrtimer
	* based cpu-clock-tick sw counter, which
	* is always available even if no PMU support:
	*/
	if (attr->type == PERF_TYPE_HARDWARE
	&& attr->config == PERF_COUNT_HW_CPU_CYCLES) {

	if (verbose)
	warning(" ... trying to fall back to cpu-clock-ticks\n");

	attr->type = PERF_TYPE_SOFTWARE;
	attr->config = PERF_COUNT_SW_CPU_CLOCK;
	goto try_again;
	}
	printf("\n");
	error("perfcounter syscall returned with %d (%s)\n",
	fd[i][counter], strerror(err));
	die("No CONFIG_PERF_COUNTERS=y kernel support configured?\n");
	exit(-1);
	}
	assert(fd[i][counter] >= 0);
	fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);

	/*
	* First counter acts as the group leader:
	*/
	if (group && group_fd == -1)
	group_fd = fd[i][counter];

	event_array[nr_poll].fd = fd[i][counter];
	event_array[nr_poll].events = POLLIN;
	nr_poll++;

	mmap_array[i][counter].counter = counter;
	mmap_array[i][counter].prev = 0;
	mmap_array[i][counter].mask = mmap_pages*page_size - 1;
	mmap_array[i][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
	PROT_READ, MAP_SHARED, fd[i][counter], 0);
	if (mmap_array[i][counter].base == MAP_FAILED)
	die("failed to mmap with %d (%s)\n", errno, strerror(errno));
	}

	static int __cmd_top(void)
	{
	pthread_t thread;
	int i, counter;
	int ret;

	for (i = 0; i < nr_cpus; i++) {
	group_fd = -1;
	for (counter = 0; counter < nr_counters; counter++)
	start_counter(i, counter);
	}

	/* Wait for a minimal set of events before starting the snapshot */
	poll(event_array, nr_poll, 100);

	mmap_read();

	if (pthread_create(&thread, NULL, display_thread, NULL)) {
	printf("Could not create display thread.\n");
	exit(-1);
	}

	if (realtime_prio) {
	struct sched_param param;

	param.sched_priority = realtime_prio;
	if (sched_setscheduler(0, SCHED_FIFO, &param)) {
	printf("Could not set realtime priority.\n");
	exit(-1);
	}
	}

	while (1) {
	int hits = samples;

	mmap_read();

	if (hits == samples)
	ret = poll(event_array, nr_poll, 100);
	}

	return 0;
	}

	static const char * const top_usage[] = {
	"perf top [<options>]",
	NULL
	};

	static const struct option options[] = {
	OPT_CALLBACK('e', "event", NULL, "event",
	"event selector. use 'perf list' to list available events",
	parse_events),
	OPT_INTEGER('c', "count", &default_interval,
	"event period to sample"),
	OPT_INTEGER('p', "pid", &target_pid,
	"profile events on existing pid"),
	OPT_BOOLEAN('a', "all-cpus", &system_wide,
	"system-wide collection from all CPUs"),
	OPT_INTEGER('C', "CPU", &profile_cpu,
	"CPU to profile on"),
	OPT_STRING('k', "vmlinux", &vmlinux, "file", "vmlinux pathname"),
	OPT_INTEGER('m', "mmap-pages", &mmap_pages,
	"number of mmap data pages"),
	OPT_INTEGER('r', "realtime", &realtime_prio,
	"collect data with this RT SCHED_FIFO priority"),
	OPT_INTEGER('d', "delay", &delay_secs,
	"number of seconds to delay between refreshes"),
	OPT_BOOLEAN('D', "dump-symtab", &dump_symtab,
	"dump the symbol table used for profiling"),
	OPT_INTEGER('f', "count-filter", &count_filter,
	"only display functions with more events than this"),
	OPT_BOOLEAN('g', "group", &group,
	"put the counters into a counter group"),
	OPT_BOOLEAN('i', "inherit", &inherit,
	"child tasks inherit counters"),
	OPT_STRING('s', "sym-filter", &sym_filter, "pattern",
	"only display symbols matchig this pattern"),
	OPT_BOOLEAN('z', "zero", &zero,
	"zero history across updates"),
	OPT_INTEGER('F', "freq", &freq,
	"profile at this frequency"),
	OPT_INTEGER('E', "entries", &print_entries,
	"display this many functions"),
	OPT_BOOLEAN('v', "verbose", &verbose,
	"be more verbose (show counter open errors, etc)"),
	OPT_END()
	};

	int cmd_top(int argc, const char *argv, const char prefix __used)
	{
	int counter;

	symbol__init();

	page_size = sysconf(_SC_PAGE_SIZE);

	argc = parse_options(argc, argv, options, top_usage, 0);
	if (argc)
	usage_with_options(top_usage, options);

	if (freq) {
	default_interval = freq;
	freq = 1;
	}

	/* CPU and PID are mutually exclusive */
	if (target_pid != -1 && profile_cpu != -1) {
	printf("WARNING: PID switch overriding CPU\n");
	sleep(1);
	profile_cpu = -1;
	}

	if (!nr_counters)
	nr_counters = 1;

	if (delay_secs < 1)
	delay_secs = 1;

	parse_symbols();

	/*
	* Fill in the ones not specifically initialized via -c:
	*/
	for (counter = 0; counter < nr_counters; counter++) {
	if (attrs[counter].sample_period)
	continue;

	attrs[counter].sample_period = default_interval;
	}

	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
	assert(nr_cpus <= MAX_NR_CPUS);
	assert(nr_cpus >= 0);

	if (target_pid != -1 \|\| profile_cpu != -1)
	nr_cpus = 1;

	return __cmd_top();
	}