trace.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

					case SInts:
						if (_e->time > prevts && _e->time <= newestts){
							sx = time2x(_e->time);
							line(screen, addpt(p, Pt(sx, topmargin)), 
												addpt(p, Pt(sx, Height / 2 - bottommargin)), 	
												Endsquare, Endsquare, 0, 
												green, ZP);
						}
						break;
					case SInte:
						if (_e->time > prevts && _e->time <= newestts) {
							sx = time2x(_e->time);
							line(screen, addpt(p, Pt(sx, Height / 2 - bottommargin)), 
												addpt(p, Pt(sx, Height - bottommargin)), 
												Endsquare, Endsquare, 0, 
												blue, ZP);
						}
						break;
					}
				}
				break;
			}
		}
		p.y += Height;
	}

	ts = prevts + scales[scaleno].littletics - (prevts % scales[scaleno].littletics);
	x = time2x(ts);

	while(x < Width){
		p = screen->r.min;
		for(n = 0; n < ntasks; n++){
			int height, width;

			/* p is upper left corner for this task */
			if ((ts % scales[scaleno].scale) == 0){
				height = 10 * Height;
				width = 1;
			}else if ((ts % scales[scaleno].bigtics) == 0){
				height = 12 * Height;
				width = 0;
			}else{
				height = 13 * Height;
				width = 0;
			}
			height >>= 4;

			line(screen, addpt(p, Pt(x, height)), addpt(p, Pt(x, Height - lineht)),
				Endsquare, Endsquare, width, cols[n % Ncolor][2], ZP);

			p.y += Height;
		}
		ts += scales[scaleno].littletics;
		x = time2x(ts);
	}

	rtime = screen->r;
	rtime.min.y = rtime.max.y - tinyfont->height + 2;
	draw(screen, rtime, bg, nil, ZP);
	ts = oldestts + scales[scaleno].bigtics - (oldestts % scales[scaleno].bigtics);
	x = time2x(ts);
	ss = 0;
	while(x < Width){
		snprint(buf, sizeof(buf), "%t", ss);
		string(screen, addpt(p, Pt(x - stringwidth(tinyfont, buf)/2, - tinyfont->height - 1)), 
			fg, ZP, tinyfont, buf);
		ts += scales[scaleno].bigtics;
		ss += scales[scaleno].bigtics;
		x = time2x(ts);
	}

	snprint(buf, sizeof(buf), "%t", now);
	string(screen, Pt(screen->r.max.x - stringwidth(mediumfont, buf), screen->r.min.y), 
		fg, ZP, mediumfont, buf);
	
	flushimage(display, 1);
	prevts = newestts;
}

Task*
newtask(ulong pid)
{
	Task *t;
	char buf[64], *p;
	int fd,n;

	tasks = realloc(tasks, (ntasks + 1) * sizeof(Task));
	assert(tasks);

	t = &tasks[ntasks++];
	memset(t, 0, sizeof(Task));
	t->events = nil;
	snprint(buf, sizeof buf, "/proc/%ld/status", pid);
	t->name = nil;
	fd = open(buf, OREAD);
	if (fd >= 0){
		n = read(fd, buf, sizeof buf);
		if(n > 0){
			p = buf + sizeof buf - 1;
			*p = 0;
			p = strchr(buf, ' ');
			if (p) *p = 0;
			t->name = strdup(buf);
		}else
			print("%s: %r\n", buf);
		close(fd);
	}else
		print("%s: %r\n", buf);
	t->pid = pid;
	prevts = 0;
	if (newwin){
		fprint(wctlfd, "resize -dx %d -dy %d\n",
			Width + 20, (ntasks * Height) + 5);
	}else
		Height = ntasks ? Dy(screen->r)/ntasks : Dy(screen->r);
	return t;
}

void
doevent(Task *t, Traceevent *ep)
{
	int i, n;
	Event *event;
	vlong runt;

	t->tevents[ep->etype & 0xffff]++;
	n = t->nevents++;
	t->events = realloc(t->events, t->nevents*sizeof(Event));
	assert(t->events);
	event = &t->events[n];
	memmove(event, ep, sizeof(Traceevent));
	event->etime = 0;

	switch(event->etype & 0xffff){
	case SRelease:
		if (t->runthis > t->runmax)
			t->runmax = t->runthis;
		t->runthis = 0;
		break;

	case SSleep:
	case SYield:
	case SReady:
	case SSlice:
		for(i = n-1; i >= 0; i--)
			if (t->events[i].etype == SRun || 
				t->events[i].etype == SEdf)
				break;
		if(i < 0 || t->events[i].etime != 0)
			break;
		runt = event->time - t->events[i].time;
		if(runt > 0){
			t->events[i].etime = event->time;
			t->runtime += runt;
			t->total += runt;
			t->runthis += runt;
			t->runs++;
		}
		break;
	case SDead:
print("task died %ld %t %s\n", event->pid, event->time, schedstatename[event->etype & 0xffff]);
		free(t->events);
		free(t->name);
		ntasks--;
		memmove(t, t+1, sizeof(Task)*(&tasks[ntasks]-t));
		if (newwin)
			fprint(wctlfd, "resize -dx %d -dy %d\n",
				Width + 20, (ntasks * Height) + 5);
		else
			Height = ntasks ? Dy(screen->r)/ntasks : Dy(screen->r);
		prevts = 0;
	}
}

void
drawtrace(void)
{
	char *wsys, line[256];
	int wfd, logfd;
	Mousectl *mousectl;
	Keyboardctl *keyboardctl;
	int scaleno;
	Rune r;
	int i, n;
	Task *t;
	Traceevent *ep;

	eventbuf = malloc(Nevents*sizeof(Traceevent));
	assert(eventbuf);

	if((logfd = open(profdev, OREAD)) < 0)
		sysfatal("%s: Cannot open %s: %r\n", argv0, profdev);

	if(newwin){
		if((wsys = getenv("wsys")) == nil)
			sysfatal("%s: Cannot find windowing system: %r\n",
						argv0);
	
		if((wfd = open(wsys, ORDWR)) < 0)
			sysfatal("%s: Cannot open windowing system: %r\n",
						argv0);
	
		snprint(line, sizeof(line), "new -pid %d -dx %d -dy %d",
				getpid(), Width + 20, Height + 5);
		line[sizeof(line) - 1] = '\0';
		rfork(RFNAMEG);
	
		if(mount(wfd, -1, "/mnt/wsys", MREPL, line) < 0) 
			sysfatal("%s: Cannot mount %s under /mnt/wsys: %r\n",
						argv0, line);
	
		if(bind("/mnt/wsys", "/dev", MBEFORE) < 0) 
			sysfatal("%s: Cannot bind /mnt/wsys in /dev: %r\n",
						argv0);
	
	}
	if((wctlfd = open("/dev/wctl", OWRITE)) < 0)
		sysfatal("%s: Cannot open /dev/wctl: %r\n", argv0);
	if(initdraw(nil, nil, "trace") < 0)
		sysfatal("%s: initdraw failure: %r\n", argv0);

	Width = Dx(screen->r);
	Height = Dy(screen->r);

	if((mousectl = initmouse(nil, screen)) == nil)
		sysfatal("%s: cannot initialize mouse: %r\n", argv0);

	if((keyboardctl = initkeyboard(nil)) == nil)
		sysfatal("%s: cannot initialize keyboard: %r\n", argv0);

	colinit();

	paused = 0;
	scaleno = 7;	/* 100 milliseconds */
	now = nsec();
	for(;;) {
		Alt a[] = {
			{ mousectl->c,			nil,		CHANRCV		},
			{ mousectl->resizec,	nil,		CHANRCV		},
			{ keyboardctl->c,		&r,			CHANRCV		},
			{ nil,					nil,		CHANNOBLK	},
		};

		switch (alt(a)) {
		case 0:
			continue;

		case 1:
			if(getwindow(display, Refnone) < 0)
				sysfatal("drawrt: Cannot re-attach window\n");
			if(newwin){
				if(Dx(screen->r) != Width || 
					Dy(screen->r) != (ntasks * Height)){
					fprint(2, "resize: x: have %d, need %d; y: have %d, need %d\n",
							Dx(screen->r), Width + 8, Dy(screen->r), (ntasks * Height) + 8);
					fprint(wctlfd, "resize -dx %d -dy %d\n", 
							Width + 8, (ntasks * Height) + 8);
				}
			}
			else{
				Width = Dx(screen->r);
				Height = ntasks? Dy(screen->r)/ntasks: 
							Dy(screen->r);
			}
			break;

		case 2:

			switch(r){
			case 'r':
				for(i = 0; i < ntasks; i++){
					tasks[i].tstart = now;
					tasks[i].total = 0;
					tasks[i].runtime = 0;
					tasks[i].runmax = 0;
					tasks[i].runthis = 0;
					tasks[i].runs = 0;
					memset(tasks[i].tevents, 0, Nevent*sizeof(ulong));
					
				}
				break;

			case 'p':
				paused ^= 1;
				prevts = 0;
				break;

			case '-':
				if (scaleno < nelem(scales) - 1)
					scaleno++;
				prevts = 0;
				break;

			case '+':
				if (scaleno > 0)
					scaleno--;
				prevts = 0;
				break;

			case 'q':
				threadexitsall(nil);

			case 'v':
				verbose ^= 1;

			default:
				break;
			}
			break;
			
		case 3:
			now = nsec();
			while((n = read(logfd, eventbuf, Nevents*sizeof(Traceevent))) > 0){
				assert((n % sizeof(Traceevent)) == 0);
				nevents = n / sizeof(Traceevent);
				for (ep = eventbuf; ep < eventbuf + nevents; ep++){
					if ((ep->etype & 0xffff) >= Nevent){
						print("%ld %t Illegal event %ld\n",
							ep->pid, ep->time, ep->etype & 0xffff);
						continue;
					}
					if (verbose)
						print("%ld %t %s\n",
							ep->pid, ep->time, schedstatename[ep->etype & 0xffff]);

					for(i = 0; i < ntasks; i++)
						if(tasks[i].pid == ep->pid)
							break;

					if(i == ntasks){
						t = newtask(ep->pid);
						t->tstart = ep->time;
					}else
						t = &tasks[i];

					doevent(t, ep);
				}
			}
			if(!paused)
				redraw(scaleno);
		}
		sleep(scales[scaleno].sleep);
	}
}

int
timeconv(Fmt *f)
{
	char buf[128], *sign;
	vlong t;

	buf[0] = 0;
	switch(f->r) {
	case 'U':
		t = va_arg(f->args, vlong);
		break;
	case 't':		// vlong in nanoseconds
		t = va_arg(f->args, vlong);
		break;
	default:
		return fmtstrcpy(f, "(timeconv)");
	}
	if (t < 0) {
		sign = "-";
		t = -t;
	}else
		sign = "";
	if (t > S(1)){
		t += OneRound;
		sprint(buf, "%s%d.%.3ds", sign, (int)(t / S(1)), (int)(t % S(1))/1000000);
	}else if (t > MS(1)){
		t += MilliRound;
		sprint(buf, "%s%d.%.3dms", sign, (int)(t / MS(1)), (int)(t % MS(1))/1000);
	}else if (t > US(1))
		sprint(buf, "%s%d.%.3dµs", sign, (int)(t / US(1)), (int)(t % US(1)));
	else
		sprint(buf, "%s%dns", sign, (int)t);
	return fmtstrcpy(f, buf);
}