#include <u.h>
#include <libc.h>
#include <bio.h>

vlong rdtsc(void);

int
ncpu(void)
{
	char buf[4096];
	int fd, i, n, nl;
	
	if((fd = open("#c/sysstat", OREAD)) < 0)
		sysfatal("open #c/sysstat: %r");
	n = read(fd, buf, sizeof buf);
	close(fd);
	nl = 0;
	for(i=0; i<n; i++)
		if(buf[i] == '\n')
			nl++;
	return nl;
}

int
pctl(char *fmt, ...)
{
	static int fd = -1;
	char buf[128];
	int n;
	va_list arg;

	if(fd < 0){
		snprint(buf, sizeof buf, "#p/%d/ctl", getpid());
		if((fd = open(buf, OWRITE)) < 0)
			sysfatal("open %s: %r", buf);
	}
	
	va_start(arg, fmt);
	n = vsnprint(buf, sizeof buf, fmt, arg);
	va_end(arg);
	return write(fd, buf, n);
}

vlong tsc0;
vlong tsc;
Biobuf bout;

void
main(void)
{
	int i, n;
	
	Binit(&bout, OWRITE, 1);
	n = ncpu();
	print("%d cpus\n", n);
	if(n <= 0)
		exits("no cpus");
	for(i=0; i<8*n; i++){
		if(pctl("wired %d", i%n) < 0)
			sysfatal("pctl: %r");
		if(rfork(RFMEM|RFPROC) == 0){
			tsc = rdtsc();
			_exits(0);
		}
		waitpid();
		if(i == 0)
			tsc0 = tsc;
		Bprint(&bout, "cpu%d: %lld %lld\n", i%n, tsc, tsc - tsc0);
		tsc0 = tsc;
	}
	Bflush(&bout);
	exits(0);
}