builtin-timechart.c

/*
 * builtin-timechart.c - make an svg timechart of system activity
 *
 * (C) Copyright 2009 Intel Corporation
 *
 * Authors:
 *     Arjan van de Ven <arjan@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */

#include "builtin.h"

#include "util/util.h"

#include "util/color.h"
#include <linux/list.h>
#include "util/cache.h"
#include <linux/rbtree.h>
#include "util/symbol.h"
#include "util/string.h"
#include "util/callchain.h"
#include "util/strlist.h"

#include "perf.h"
#include "util/header.h"
#include "util/parse-options.h"
#include "util/parse-events.h"
#include "util/svghelper.h"

static char		const *input_name = "perf.data";
static char		const *output_name = "output.svg";


static unsigned long	page_size;
static unsigned long	mmap_window = 32;
static u64		sample_type;

static unsigned int	numcpus;
static u64		min_freq;	/* Lowest CPU frequency seen */
static u64		max_freq;	/* Highest CPU frequency seen */
static u64		turbo_frequency;

static u64		first_time, last_time;

static int		power_only;


static struct perf_header	*header;

struct per_pid;
struct per_pidcomm;

struct cpu_sample;
struct power_event;
struct wake_event;

struct sample_wrapper;

/*
 * Datastructure layout:
 * We keep an list of "pid"s, matching the kernels notion of a task struct.
 * Each "pid" entry, has a list of "comm"s.
 *	this is because we want to track different programs different, while
 *	exec will reuse the original pid (by design).
 * Each comm has a list of samples that will be used to draw
 * final graph.
 */

struct per_pid {
	struct per_pid *next;

	int		pid;
	int		ppid;

	u64		start_time;
	u64		end_time;
	u64		total_time;
	int		display;

	struct per_pidcomm *all;
	struct per_pidcomm *current;

	int painted;
};


struct per_pidcomm {
	struct per_pidcomm *next;

	u64		start_time;
	u64		end_time;
	u64		total_time;

	int		Y;
	int		display;

	long		state;
	u64		state_since;

	char		*comm;

	struct cpu_sample *samples;
};

struct sample_wrapper {
	struct sample_wrapper *next;

	u64		timestamp;
	unsigned char	data[0];
};

#define TYPE_NONE	0
#define TYPE_RUNNING	1
#define TYPE_WAITING	2
#define TYPE_BLOCKED	3

struct cpu_sample {
	struct cpu_sample *next;

	u64 start_time;
	u64 end_time;
	int type;
	int cpu;
};

static struct per_pid *all_data;

#define CSTATE 1
#define PSTATE 2

struct power_event {
	struct power_event *next;
	int type;
	int state;
	u64 start_time;
	u64 end_time;
	int cpu;
};

struct wake_event {
	struct wake_event *next;
	int waker;
	int wakee;
	u64 time;
};

static struct power_event    *power_events;
static struct wake_event     *wake_events;

struct sample_wrapper *all_samples;

static struct per_pid *find_create_pid(int pid)
{
	struct per_pid *cursor = all_data;

	while (cursor) {
		if (cursor->pid == pid)
			return cursor;
		cursor = cursor->next;
	}
	cursor = malloc(sizeof(struct per_pid));
	assert(cursor != NULL);
	memset(cursor, 0, sizeof(struct per_pid));
	cursor->pid = pid;
	cursor->next = all_data;
	all_data = cursor;
	return cursor;
}

static void pid_set_comm(int pid, char *comm)
{
	struct per_pid *p;
	struct per_pidcomm *c;
	p = find_create_pid(pid);
	c = p->all;
	while (c) {
		if (c->comm && strcmp(c->comm, comm) == 0) {
			p->current = c;
			return;
		}
		if (!c->comm) {
			c->comm = strdup(comm);
			p->current = c;
			return;
		}
		c = c->next;
	}
	c = malloc(sizeof(struct per_pidcomm));
	assert(c != NULL);
	memset(c, 0, sizeof(struct per_pidcomm));
	c->comm = strdup(comm);
	p->current = c;
	c->next = p->all;
	p->all = c;
}

static void pid_fork(int pid, int ppid, u64 timestamp)
{
	struct per_pid *p, *pp;
	p = find_create_pid(pid);
	pp = find_create_pid(ppid);
	p->ppid = ppid;
	if (pp->current && pp->current->comm && !p->current)
		pid_set_comm(pid, pp->current->comm);

	p->start_time = timestamp;
	if (p->current) {
		p->current->start_time = timestamp;
		p->current->state_since = timestamp;
	}
}

static void pid_exit(int pid, u64 timestamp)
{
	struct per_pid *p;
	p = find_create_pid(pid);
	p->end_time = timestamp;
	if (p->current)
		p->current->end_time = timestamp;
}

static void
pid_put_sample(int pid, int type, unsigned int cpu, u64 start, u64 end)
{
	struct per_pid *p;
	struct per_pidcomm *c;
	struct cpu_sample *sample;

	p = find_create_pid(pid);
	c = p->current;
	if (!c) {
		c = malloc(sizeof(struct per_pidcomm));
		assert(c != NULL);
		memset(c, 0, sizeof(struct per_pidcomm));
		p->current = c;
		c->next = p->all;
		p->all = c;
	}

	sample = malloc(sizeof(struct cpu_sample));
	assert(sample != NULL);
	memset(sample, 0, sizeof(struct cpu_sample));
	sample->start_time = start;
	sample->end_time = end;
	sample->type = type;
	sample->next = c->samples;
	sample->cpu = cpu;
	c->samples = sample;

	if (sample->type == TYPE_RUNNING && end > start && start > 0) {
		c->total_time += (end-start);
		p->total_time += (end-start);
	}

	if (c->start_time == 0 || c->start_time > start)
		c->start_time = start;
	if (p->start_time == 0 || p->start_time > start)
		p->start_time = start;

	if (cpu > numcpus)
		numcpus = cpu;
}

#define MAX_CPUS 4096

static u64 cpus_cstate_start_times[MAX_CPUS];
static int cpus_cstate_state[MAX_CPUS];
static u64 cpus_pstate_start_times[MAX_CPUS];
static u64 cpus_pstate_state[MAX_CPUS];

static int
process_comm_event(event_t *event)
{
	pid_set_comm(event->comm.pid, event->comm.comm);
	return 0;
}
static int
process_fork_event(event_t *event)
{
	pid_fork(event->fork.pid, event->fork.ppid, event->fork.time);
	return 0;
}

static int
process_exit_event(event_t *event)
{
	pid_exit(event->fork.pid, event->fork.time);
	return 0;
}

struct trace_entry {
	u32			size;
	unsigned short		type;
	unsigned char		flags;
	unsigned char		preempt_count;
	int			pid;
	int			tgid;
};

struct power_entry {
	struct trace_entry te;
	s64	type;
	s64	value;
};

#define TASK_COMM_LEN 16
struct wakeup_entry {
	struct trace_entry te;
	char comm[TASK_COMM_LEN];
	int   pid;
	int   prio;
	int   success;
};

/*
 * trace_flag_type is an enumeration that holds different
 * states when a trace occurs. These are:
 *  IRQS_OFF            - interrupts were disabled
 *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
 *  NEED_RESCED         - reschedule is requested
 *  HARDIRQ             - inside an interrupt handler
 *  SOFTIRQ             - inside a softirq handler
 */
enum trace_flag_type {
	TRACE_FLAG_IRQS_OFF		= 0x01,
	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
	TRACE_FLAG_NEED_RESCHED		= 0x04,
	TRACE_FLAG_HARDIRQ		= 0x08,
	TRACE_FLAG_SOFTIRQ		= 0x10,
};



struct sched_switch {
	struct trace_entry te;
	char prev_comm[TASK_COMM_LEN];
	int  prev_pid;
	int  prev_prio;
	long prev_state; /* Arjan weeps. */
	char next_comm[TASK_COMM_LEN];
	int  next_pid;
	int  next_prio;
};

static void c_state_start(int cpu, u64 timestamp, int state)
{
	cpus_cstate_start_times[cpu] = timestamp;
	cpus_cstate_state[cpu] = state;
}

static void c_state_end(int cpu, u64 timestamp)
{
	struct power_event *pwr;
	pwr = malloc(sizeof(struct power_event));
	if (!pwr)
		return;
	memset(pwr, 0, sizeof(struct power_event));

	pwr->state = cpus_cstate_state[cpu];
	pwr->start_time = cpus_cstate_start_times[cpu];
	pwr->end_time = timestamp;
	pwr->cpu = cpu;
	pwr->type = CSTATE;
	pwr->next = power_events;

	power_events = pwr;
}

static void p_state_change(int cpu, u64 timestamp, u64 new_freq)
{
	struct power_event *pwr;
	pwr = malloc(sizeof(struct power_event));

	if (new_freq > 8000000) /* detect invalid data */
		return;

	if (!pwr)
		return;
	memset(pwr, 0, sizeof(struct power_event));

	pwr->state = cpus_pstate_state[cpu];
	pwr->start_time = cpus_pstate_start_times[cpu];
	pwr->end_time = timestamp;
	pwr->cpu = cpu;
	pwr->type = PSTATE;
	pwr->next = power_events;

	if (!pwr->start_time)
		pwr->start_time = first_time;

	power_events = pwr;

	cpus_pstate_state[cpu] = new_freq;
	cpus_pstate_start_times[cpu] = timestamp;

	if ((u64)new_freq > max_freq)
		max_freq = new_freq;

	if (new_freq < min_freq || min_freq == 0)
		min_freq = new_freq;

	if (new_freq == max_freq - 1000)
			turbo_frequency = max_freq;
}

static void
sched_wakeup(int cpu, u64 timestamp, int pid, struct trace_entry *te)
{
	struct wake_event *we;
	struct per_pid *p;
	struct wakeup_entry *wake = (void *)te;

	we = malloc(sizeof(struct wake_event));
	if (!we)
		return;

	memset(we, 0, sizeof(struct wake_event));
	we->time = timestamp;
	we->waker = pid;

	if ((te->flags & TRACE_FLAG_HARDIRQ) || (te->flags & TRACE_FLAG_SOFTIRQ))
		we->waker = -1;

	we->wakee = wake->pid;
	we->next = wake_events;
	wake_events = we;
	p = find_create_pid(we->wakee);

	if (p && p->current && p->current->state == TYPE_NONE) {
		p->current->state_since = timestamp;
		p->current->state = TYPE_WAITING;
	}
	if (p && p->current && p->current->state == TYPE_BLOCKED) {
		pid_put_sample(p->pid, p->current->state, cpu, p->current->state_since, timestamp);
		p->current->state_since = timestamp;
		p->current->state = TYPE_WAITING;
	}
}

static void sched_switch(int cpu, u64 timestamp, struct trace_entry *te)
{
	struct per_pid *p = NULL, *prev_p;
	struct sched_switch *sw = (void *)te;


	prev_p = find_create_pid(sw->prev_pid);

	p = find_create_pid(sw->next_pid);

	if (prev_p->current && prev_p->current->state != TYPE_NONE)
		pid_put_sample(sw->prev_pid, TYPE_RUNNING, cpu, prev_p->current->state_since, timestamp);
	if (p && p->current) {
		if (p->current->state != TYPE_NONE)
			pid_put_sample(sw->next_pid, p->current->state, cpu, p->current->state_since, timestamp);

			p->current->state_since = timestamp;
			p->current->state = TYPE_RUNNING;
	}

	if (prev_p->current) {
		prev_p->current->state = TYPE_NONE;
		prev_p->current->state_since = timestamp;
		if (sw->prev_state & 2)
			prev_p->current->state = TYPE_BLOCKED;
		if (sw->prev_state == 0)
			prev_p->current->state = TYPE_WAITING;
	}
}


static int
process_sample_event(event_t *event)
{
	int cursor = 0;
	u64 addr = 0;
	u64 stamp = 0;
	u32 cpu = 0;
	u32 pid = 0;
	struct trace_entry *te;

	if (sample_type & PERF_SAMPLE_IP)
		cursor++;

	if (sample_type & PERF_SAMPLE_TID) {
		pid = event->sample.array[cursor]>>32;
		cursor++;
	}
	if (sample_type & PERF_SAMPLE_TIME) {
		stamp = event->sample.array[cursor++];

		if (!first_time || first_time > stamp)
			first_time = stamp;
		if (last_time < stamp)
			last_time = stamp;

	}
	if (sample_type & PERF_SAMPLE_ADDR)
		addr = event->sample.array[cursor++];
	if (sample_type & PERF_SAMPLE_ID)
		cursor++;
	if (sample_type & PERF_SAMPLE_STREAM_ID)
		cursor++;
	if (sample_type & PERF_SAMPLE_CPU)
		cpu = event->sample.array[cursor++] & 0xFFFFFFFF;
	if (sample_type & PERF_SAMPLE_PERIOD)
		cursor++;

	te = (void *)&event->sample.array[cursor];

	if (sample_type & PERF_SAMPLE_RAW && te->size > 0) {
		char *event_str;
		struct power_entry *pe;

		pe = (void *)te;

		event_str = perf_header__find_event(te->type);

		if (!event_str)
			return 0;

		if (strcmp(event_str, "power:power_start") == 0)
			c_state_start(cpu, stamp, pe->value);

		if (strcmp(event_str, "power:power_end") == 0)
			c_state_end(cpu, stamp);

		if (strcmp(event_str, "power:power_frequency") == 0)
			p_state_change(cpu, stamp, pe->value);

		if (strcmp(event_str, "sched:sched_wakeup") == 0)
			sched_wakeup(cpu, stamp, pid, te);

		if (strcmp(event_str, "sched:sched_switch") == 0)
			sched_switch(cpu, stamp, te);
	}
	return 0;
}

/*
 * After the last sample we need to wrap up the current C/P state
 * and close out each CPU for these.
 */
static void end_sample_processing(void)
{
	u64 cpu;
	struct power_event *pwr;

	for (cpu = 0; cpu <= numcpus; cpu++) {
		pwr = malloc(sizeof(struct power_event));
		if (!pwr)
			return;
		memset(pwr, 0, sizeof(struct power_event));

		/* C state */
#if 0
		pwr->state = cpus_cstate_state[cpu];
		pwr->start_time = cpus_cstate_start_times[cpu];
		pwr->end_time = last_time;
		pwr->cpu = cpu;
		pwr->type = CSTATE;
		pwr->next = power_events;

		power_events = pwr;
#endif
		/* P state */

		pwr = malloc(sizeof(struct power_event));
		if (!pwr)
			return;
		memset(pwr, 0, sizeof(struct power_event));

		pwr->state = cpus_pstate_state[cpu];
		pwr->start_time = cpus_pstate_start_times[cpu];
		pwr->end_time = last_time;
		pwr->cpu = cpu;
		pwr->type = PSTATE;
		pwr->next = power_events;

		if (!pwr->start_time)
			pwr->start_time = first_time;
		if (!pwr->state)
			pwr->state = min_freq;
		power_events = pwr;
	}
}

static u64 sample_time(event_t *event)
{
	int cursor;

	cursor = 0;
	if (sample_type & PERF_SAMPLE_IP)
		cursor++;
	if (sample_type & PERF_SAMPLE_TID)
		cursor++;
	if (sample_type & PERF_SAMPLE_TIME)
		return event->sample.array[cursor];
	return 0;
}


/*
 * We first queue all events, sorted backwards by insertion.
 * The order will get flipped later.
 */
static int
queue_sample_event(event_t *event)
{
	struct sample_wrapper *copy, *prev;
	int size;

	size = event->sample.header.size + sizeof(struct sample_wrapper) + 8;

	copy = malloc(size);
	if (!copy)
		return 1;

	memset(copy, 0, size);

	copy->next = NULL;
	copy->timestamp = sample_time(event);

	memcpy(&copy->data, event, event->sample.header.size);

	/* insert in the right place in the list */

	if (!all_samples) {
		/* first sample ever */
		all_samples = copy;
		return 0;
	}

	if (all_samples->timestamp < copy->timestamp) {
		/* insert at the head of the list */
		copy->next = all_samples;
		all_samples = copy;
		return 0;
	}

	prev = all_samples;
	while (prev->next) {
		if (prev->next->timestamp < copy->timestamp) {
			copy->next = prev->next;
			prev->next = copy;
			return 0;
		}
		prev = prev->next;
	}
	/* insert at the end of the list */
	prev->next = copy;

	return 0;
}

static void sort_queued_samples(void)
{
	struct sample_wrapper *cursor, *next;

	cursor = all_samples;
	all_samples = NULL;

	while (cursor) {
		next = cursor->next;
		cursor->next = all_samples;
		all_samples = cursor;
		cursor = next;
	}
}

/*
 * Sort the pid datastructure
 */
static void sort_pids(void)
{
	struct per_pid *new_list, *p, *cursor, *prev;
	/* sort by ppid first, then by pid, lowest to highest */

	new_list = NULL;

	while (all_data) {
		p = all_data;
		all_data = p->next;
		p->next = NULL;

		if (new_list == NULL) {
			new_list = p;
			p->next = NULL;
			continue;
		}
		prev = NULL;
		cursor = new_list;
		while (cursor) {
			if (cursor->ppid > p->ppid ||
				(cursor->ppid == p->ppid && cursor->pid > p->pid)) {
				/* must insert before */
				if (prev) {
					p->next = prev->next;
					prev->next = p;
					cursor = NULL;
					continue;
				} else {
					p->next = new_list;
					new_list = p;
					cursor = NULL;
					continue;
				}
			}

			prev = cursor;
			cursor = cursor->next;
			if (!cursor)
				prev->next = p;
		}
	}
	all_data = new_list;
}


static void draw_c_p_states(void)
{
	struct power_event *pwr;
	pwr = power_events;

	/*
	 * two pass drawing so that the P state bars are on top of the C state blocks
	 */
	while (pwr) {
		if (pwr->type == CSTATE)
			svg_cstate(pwr->cpu, pwr->start_time, pwr->end_time, pwr->state);
		pwr = pwr->next;
	}

	pwr = power_events;
	while (pwr) {
		if (pwr->type == PSTATE) {
			if (!pwr->state)
				pwr->state = min_freq;
			svg_pstate(pwr->cpu, pwr->start_time, pwr->end_time, pwr->state);
		}
		pwr = pwr->next;
	}
}

static void draw_wakeups(void)
{
	struct wake_event *we;
	struct per_pid *p;
	struct per_pidcomm *c;

	we = wake_events;
	while (we) {
		int from = 0, to = 0;
		char *task_from = NULL, *task_to = NULL;

		/* locate the column of the waker and wakee */
		p = all_data;
		while (p) {
			if (p->pid == we->waker || p->pid == we->wakee) {
				c = p->all;
				while (c) {
					if (c->Y && c->start_time <= we->time && c->end_time >= we->time) {
						if (p->pid == we->waker) {
							from = c->Y;
							task_from = c->comm;
						}
						if (p->pid == we->wakee) {
							to = c->Y;
							task_to = c->comm;
						}
					}
					c = c->next;
				}
			}
			p = p->next;
		}

		if (we->waker == -1)
			svg_interrupt(we->time, to);
		else if (from && to && abs(from - to) == 1)
			svg_wakeline(we->time, from, to);
		else
			svg_partial_wakeline(we->time, from, task_from, to, task_to);
		we = we->next;
	}
}

static void draw_cpu_usage(void)
{
	struct per_pid *p;
	struct per_pidcomm *c;
	struct cpu_sample *sample;
	p = all_data;
	while (p) {
		c = p->all;
		while (c) {
			sample = c->samples;
			while (sample) {
				if (sample->type == TYPE_RUNNING)
					svg_process(sample->cpu, sample->start_time, sample->end_time, "sample", c->comm);

				sample = sample->next;
			}
			c = c->next;
		}
		p = p->next;
	}
}

static void draw_process_bars(void)
{
	struct per_pid *p;
	struct per_pidcomm *c;
	struct cpu_sample *sample;
	int Y = 0;

	Y = 2 * numcpus + 2;

	p = all_data;
	while (p) {
		c = p->all;
		while (c) {
			if (!c->display) {
				c->Y = 0;
				c = c->next;
				continue;
			}

			svg_box(Y, c->start_time, c->end_time, "process");
			sample = c->samples;
			while (sample) {
				if (sample->type == TYPE_RUNNING)
					svg_sample(Y, sample->cpu, sample->start_time, sample->end_time);
				if (sample->type == TYPE_BLOCKED)
					svg_box(Y, sample->start_time, sample->end_time, "blocked");
				if (sample->type == TYPE_WAITING)
					svg_waiting(Y, sample->start_time, sample->end_time);
				sample = sample->next;
			}

			if (c->comm) {
				char comm[256];
				if (c->total_time > 5000000000) /* 5 seconds */
					sprintf(comm, "%s:%i (%2.2fs)", c->comm, p->pid, c->total_time / 1000000000.0);
				else
					sprintf(comm, "%s:%i (%3.1fms)", c->comm, p->pid, c->total_time / 1000000.0);

				svg_text(Y, c->start_time, comm);
			}
			c->Y = Y;
			Y++;
			c = c->next;
		}
		p = p->next;
	}
}

static int determine_display_tasks(u64 threshold)
{
	struct per_pid *p;
	struct per_pidcomm *c;
	int count = 0;

	p = all_data;
	while (p) {
		p->display = 0;
		if (p->start_time == 1)
			p->start_time = first_time;

		/* no exit marker, task kept running to the end */
		if (p->end_time == 0)
			p->end_time = last_time;
		if (p->total_time >= threshold && !power_only)
			p->display = 1;

		c = p->all;

		while (c) {
			c->display = 0;

			if (c->start_time == 1)
				c->start_time = first_time;

			if (c->total_time >= threshold && !power_only) {
				c->display = 1;
				count++;
			}

			if (c->end_time == 0)
				c->end_time = last_time;

			c = c->next;
		}
		p = p->next;
	}
	return count;
}



#define TIME_THRESH 10000000

static void write_svg_file(const char *filename)
{
	u64 i;
	int count;

	numcpus++;


	count = determine_display_tasks(TIME_THRESH);

	/* We'd like to show at least 15 tasks; be less picky if we have fewer */
	if (count < 15)
		count = determine_display_tasks(TIME_THRESH / 10);

	open_svg(filename, numcpus, count, first_time, last_time);

	svg_time_grid();
	svg_legenda();

	for (i = 0; i < numcpus; i++)
		svg_cpu_box(i, max_freq, turbo_frequency);

	draw_cpu_usage();
	draw_process_bars();
	draw_c_p_states();
	draw_wakeups();

	svg_close();
}

static int
process_event(event_t *event)
{

	switch (event->header.type) {

	case PERF_RECORD_COMM:
		return process_comm_event(event);
	case PERF_RECORD_FORK:
		return process_fork_event(event);
	case PERF_RECORD_EXIT:
		return process_exit_event(event);
	case PERF_RECORD_SAMPLE:
		return queue_sample_event(event);

	/*
	 * We dont process them right now but they are fine:
	 */
	case PERF_RECORD_MMAP:
	case PERF_RECORD_THROTTLE:
	case PERF_RECORD_UNTHROTTLE:
		return 0;

	default:
		return -1;
	}

	return 0;
}

static void process_samples(void)
{
	struct sample_wrapper *cursor;
	event_t *event;

	sort_queued_samples();

	cursor = all_samples;
	while (cursor) {
		event = (void *)&cursor->data;
		cursor = cursor->next;
		process_sample_event(event);
	}
}


static int __cmd_timechart(void)
{
	int ret, rc = EXIT_FAILURE;
	unsigned long offset = 0;
	unsigned long head, shift;
	struct stat statbuf;
	event_t *event;
	uint32_t size;
	char *buf;
	int input;

	input = open(input_name, O_RDONLY);
	if (input < 0) {
		fprintf(stderr, " failed to open file: %s", input_name);
		if (!strcmp(input_name, "perf.data"))
			fprintf(stderr, "  (try 'perf record' first)");
		fprintf(stderr, "\n");
		exit(-1);
	}

	ret = fstat(input, &statbuf);
	if (ret < 0) {
		perror("failed to stat file");
		exit(-1);
	}

	if (!statbuf.st_size) {
		fprintf(stderr, "zero-sized file, nothing to do!\n");
		exit(0);
	}

	header = perf_header__read(input);
	head = header->data_offset;

	sample_type = perf_header__sample_type(header);

	shift = page_size * (head / page_size);
	offset += shift;
	head -= shift;

remap:
	buf = (char *)mmap(NULL, page_size * mmap_window, PROT_READ,
			   MAP_SHARED, input, offset);
	if (buf == MAP_FAILED) {
		perror("failed to mmap file");
		exit(-1);
	}

more:
	event = (event_t *)(buf + head);

	size = event->header.size;
	if (!size)
		size = 8;

	if (head + event->header.size >= page_size * mmap_window) {
		int ret2;

		shift = page_size * (head / page_size);

		ret2 = munmap(buf, page_size * mmap_window);
		assert(ret2 == 0);

		offset += shift;
		head -= shift;
		goto remap;
	}

	size = event->header.size;

	if (!size || process_event(event) < 0) {

		printf("%p [%p]: skipping unknown header type: %d\n",
			(void *)(offset + head),
			(void *)(long)(event->header.size),
			event->header.type);

		/*
		 * assume we lost track of the stream, check alignment, and
		 * increment a single u64 in the hope to catch on again 'soon'.
		 */

		if (unlikely(head & 7))
			head &= ~7ULL;

		size = 8;
	}

	head += size;

	if (offset + head >= header->data_offset + header->data_size)
		goto done;

	if (offset + head < (unsigned long)statbuf.st_size)
		goto more;

done:
	rc = EXIT_SUCCESS;
	close(input);


	process_samples();

	end_sample_processing();

	sort_pids();

	write_svg_file(output_name);

	printf("Written %2.1f seconds of trace to %s.\n", (last_time - first_time) / 1000000000.0, output_name);

	return rc;
}

static const char * const timechart_usage[] = {
	"perf timechart [<options>] {record}",
	NULL
};

static const char *record_args[] = {
	"record",
	"-a",
	"-R",
	"-M",
	"-f",
	"-c", "1",
	"-e", "power:power_start",
	"-e", "power:power_end",
	"-e", "power:power_frequency",
	"-e", "sched:sched_wakeup",
	"-e", "sched:sched_switch",
};

static int __cmd_record(int argc, const char **argv)
{
	unsigned int rec_argc, i, j;
	const char **rec_argv;

	rec_argc = ARRAY_SIZE(record_args) + argc - 1;
	rec_argv = calloc(rec_argc + 1, sizeof(char *));

	for (i = 0; i < ARRAY_SIZE(record_args); i++)
		rec_argv[i] = strdup(record_args[i]);

	for (j = 1; j < (unsigned int)argc; j++, i++)
		rec_argv[i] = argv[j];

	return cmd_record(i, rec_argv, NULL);
}

static const struct option options[] = {
	OPT_STRING('i', "input", &input_name, "file",
		    "input file name"),
	OPT_STRING('o', "output", &output_name, "file",
		    "output file name"),
	OPT_INTEGER('w', "width", &svg_page_width,
		    "page width"),
	OPT_BOOLEAN('p', "power-only", &power_only,
		    "output power data only"),
	OPT_END()
};


int cmd_timechart(int argc, const char **argv, const char *prefix __used)
{
	symbol__init();

	page_size = getpagesize();

	argc = parse_options(argc, argv, options, timechart_usage,
			PARSE_OPT_STOP_AT_NON_OPTION);

	if (argc && !strncmp(argv[0], "rec", 3))
		return __cmd_record(argc, argv);
	else if (argc)
		usage_with_options(timechart_usage, options);

	setup_pager();

	return __cmd_timechart();
}