Re: [Xen-devel] inaccurate dirty_count from XEN_DOMCTL_SHADOW_OP

2017-03-30 Thread Olaf Hering 
Am Thu, 30 Mar 2017 12:40:34 +0100
schrieb Andrew Cooper :

> On 22/03/17 10:59, Olaf Hering wrote:
> > On Wed, Mar 22, Olaf Hering wrote:
> >  
> >> Did the xc_shadow_control API change at some point?  
> > ... staging-4.5 works, while staging-4.6 does not.  
> 
> Can you describe in a little more detail what you are testing?

In the PV domU I run this memdirty tool to touch an amount of pages.
In the dom0 I run logdirty to see how many pages are dirty. With older Xen 
version the rate of dirty pages is high and constant. With 4.6+ the rate goes 
down after a while.

If you have trouble with reproducing I will prepare a simple testcase.

Olaf


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Re: [Xen-devel] inaccurate dirty_count from XEN_DOMCTL_SHADOW_OP

2017-03-30 Thread Andrew Cooper 
On 22/03/17 10:59, Olaf Hering wrote:
> On Wed, Mar 22, Olaf Hering wrote:
>
>> Did the xc_shadow_control API change at some point?
> ... staging-4.5 works, while staging-4.6 does not.

Can you describe in a little more detail what you are testing?

I have tried reproducing your scenario, and I don't observe any dropoff
with 4.7 or staging.

~Andrew

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Re: [Xen-devel] inaccurate dirty_count from XEN_DOMCTL_SHADOW_OP

2017-03-22 Thread Olaf Hering 
On Wed, Mar 22, Olaf Hering wrote:

> Did the xc_shadow_control API change at some point?

... staging-4.5 works, while staging-4.6 does not.


Olaf


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Re: [Xen-devel] inaccurate dirty_count from XEN_DOMCTL_SHADOW_OP

2017-03-22 Thread Andrew Cooper 
On 22/03/17 10:46, Olaf Hering wrote:
> On Tue, Mar 21, Olaf Hering wrote:
>
>> I wonder if the usage of xc_shadow_control is correct. The testing was
>> done with a xen-4.4 based dom0, I will verify with staging once I find
>> the time.
> It does work with xen-4.4, but fails with staging.
> Did the xc_shadow_control API change at some point?

The API not, but the the method of obtaining the bitmap was changed to
make HVM control domains usable as part of the PVHv2 work, although this
was now a release or two ago.

Sorry I haven't replied yet - I did see your email, but haven't had a
chance to try it out yet.  It certainly looks like a real bug.

~Andrew

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Re: [Xen-devel] inaccurate dirty_count from XEN_DOMCTL_SHADOW_OP

2017-03-22 Thread Olaf Hering 
On Tue, Mar 21, Olaf Hering wrote:

> I wonder if the usage of xc_shadow_control is correct. The testing was
> done with a xen-4.4 based dom0, I will verify with staging once I find
> the time.

It does work with xen-4.4, but fails with staging.
Did the xc_shadow_control API change at some point?

Olaf


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[Xen-devel] inaccurate dirty_count from XEN_DOMCTL_SHADOW_OP

2017-03-21 Thread Olaf Hering 
To measure how many dirty pages a domU creates within a timeframe the
attached tool was created, based on code from xc_domain_save.
Once the domU touches many pages the reported dirty rate is high, but
after a few seconds the rate drops down from thousands to just a few dozen.

I wonder if the usage of xc_shadow_control is correct. The testing was
done with a xen-4.4 based dom0, I will verify with staging once I find
the time.


Olaf
/* gcc -Wall -o logdirty -O -lxenctrl logdirty.c */
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PAGE_SHIFT  XC_PAGE_SHIFT
#define ROUNDUP(_x,_w) (((unsigned long)(_x)+(1UL<<(_w))-1) & ~((1UL<<(_w))-1))
#define NRPAGES(x) (ROUNDUP(x, PAGE_SHIFT) >> PAGE_SHIFT)
#define BITS_PER_LONG (sizeof(unsigned long) * 8)
#define ORDER_LONG (sizeof(unsigned long) == 4 ? 5 : 6)


static unsigned int domid = 0;
static xc_interface *xch;

static unsigned long xdmg(xc_interface *c, unsigned int d)
{
	unsigned long r;
#if XEN_DOMCTL_INTERFACE_VERSION < 0x0b
	r = xc_domain_maximum_gpfn(c, d);
#else
	xen_pfn_t gpfns = 0;
	r = xc_domain_maximum_gpfn(c, d, );
#endif
	return r + 1;
}
static void sigint_handler(int sig)
{
	int rc;
	fprintf(stderr, "User aborted\n");
	rc = xc_shadow_control(xch, domid, XEN_DOMCTL_SHADOW_OP_OFF, NULL, 0, NULL, 0, NULL);
if (rc < 0)
perror("XEN_DOMCTL_SHADOW_OP_OFF hypercall failed\n");
	exit(1);
}


static inline int bitmap_size(int nr_bits)
{
	int nr_long, nr_bytes;
	nr_long = (nr_bits + BITS_PER_LONG - 1) >> ORDER_LONG;
	nr_bytes = nr_long * sizeof(unsigned long);
	return nr_bytes;
}

int main(int argc, char *argv[])
{
	int rc, ret = 1, i, runs = 42;
	unsigned int lflags;
	xentoollog_level lvl;
	xentoollog_logger *l;
	DECLARE_HYPERCALL_BUFFER(unsigned long, to_skip);
	unsigned long p2m_size;
	xc_shadow_op_stats_t stats;

	errno = EINVAL;
	if (argc > 1)
		domid = atoi(argv[1]);
	if (!domid)
		goto out;

	errno = 0;
	lvl = XTL_DEBUG;
	lflags = XTL_STDIOSTREAM_SHOW_PID | XTL_STDIOSTREAM_HIDE_PROGRESS;
	l = (xentoollog_logger *) xtl_createlogger_stdiostream(stderr, lvl, lflags);
	if (!l)
		goto out;

	xch = xc_interface_open(l, 0, 0);
	if (!xch)
		goto out;

	p2m_size = xdmg(xch, domid);
	if (!p2m_size)
		goto out;

	to_skip = xc_hypercall_buffer_alloc_pages(xch, to_skip, NRPAGES(bitmap_size(p2m_size)));
	if (!to_skip)
		goto out;

	signal(SIGINT, sigint_handler);

	rc = xc_shadow_control(xch, domid, XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY, NULL, 0, NULL, 0, NULL);
	if (rc < 0) {
		rc = xc_shadow_control(xch, domid, XEN_DOMCTL_SHADOW_OP_OFF, NULL, 0, NULL, 0, NULL);
		if (rc < 0)
			goto out;

		rc = xc_shadow_control(xch, domid, XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY, NULL, 0, NULL, 0, NULL);
		if (rc < 0)
			goto out;
	}

	rc = xc_shadow_control(xch, domid, XEN_DOMCTL_SHADOW_OP_CLEAN, NULL, 0, NULL, 0, NULL);
	if (rc < 0)
		goto out;

	for (i = 0; i < runs; i++) {
		sleep(1);
		if (1)
			rc = xc_shadow_control(xch, domid, XEN_DOMCTL_SHADOW_OP_CLEAN, HYPERCALL_BUFFER(to_skip), p2m_size, NULL, 0, );
		if (rc < 0)
			goto out;
		printf("%d: faults= %" PRIu32 " dirty= %" PRIu32 "\n", i, stats.fault_count, stats.dirty_count);
	}
	rc = xc_shadow_control(xch, domid, XEN_DOMCTL_SHADOW_OP_OFF, NULL, 0, NULL, 0, NULL);
	if (rc < 0)
		goto out;
	errno = ret = 0;
  out:
	perror(argv[0]);
	return ret;
}
/* gcc -Wall -o memdirty memdirty.c */
#include 
#include 
#include 
#include 
#include 

static void usage(const char *prog, FILE * out)
{
	fprintf(out, "usage: %s allocsize\n", prog);
	fprintf(out, " allocsize is kbytes, or number[KMGP] (P = pages)\n");
	exit(out == stderr);
}

int main(int argc, char *argv[])
{
	long long kbtotal = 0, pages, i;
	unsigned offset;
	char *mem, *tmp;

	if (argc == 2) {
		char *end = NULL;
		kbtotal = strtoull(argv[1], , 0);

		switch (*end) {
		case 'g':
		case 'G':
			kbtotal *= 1024;
		case 'm':
		case 'M':
			kbtotal *= 1024;
		case '\0':
		case 'k':
		case 'K':
			break;
		case 'p':
		case 'P':
			kbtotal *= 4;
			break;
		default:
			usage(argv[0], stderr);
			break;
		}
	}

	if (argc != 2 || kbtotal == 0)
		usage(argv[0], stderr);

	pages = kbtotal / 4;
	errno = 0;
	printf("[%d] allocating %lld kbytes, %lld pages\n", getpid(), kbtotal, pages);
	mem = calloc(pages, 4096);
	perror("calloc");
	if (mem == NULL)
		exit(1);

	offset = 0;
	while (1) {
		for (i = 0; i < pages; i++) {
			tmp = (mem + (i * 4096)) + (offset++ & (4096 - 1));
			*tmp = *tmp + 1;
		}
	}
	return 0;
}


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