在 2015-07-06, Mon, 16:11:02 ,Andrew Cooper 写到：
On 06/07/2015 08:58, xinyue wrote:
在 2015-07-06, Mon, 15:44:53 ,Andrew Cooper 写到：
On 06/07/2015 08:22, xinyue wrote:
Hi,
For I want
to translate the virtual address in HVM DomU to virtual address in Xen. But
when I use the function paging_gva_to_gfn and get_gfn, I can feel the
performance down quickly, the machine become very hot and then I have to force
the machine shutting down.
Your machine clearly isn't cooled
sufficiently, which is the first problem.
The codes I used as below:
uint32_t
pfec = PFEC_page_present;
unsigned
long gfn;
unsigned
long mfn;
unsigned
long virtaddr;
struct vcpu
*vcpu = current;
struct
domain *d = vcpu->domain;
p2m_type_t t;
gfn =
paging_gva_to_gfn(current, 0xc0290000, &pfec);
mfn =
get_gfn(d, gfn, &t);
virtaddr =
map_domain_page(mfn_x(mfn));
I also use the dbg_hvm_va2mfn
function in debug.c, performance problem still present.
Walking pagetables in software is slow.
There is no getting around this.
Your performance problems will be caused by
performing the operation far too often. You should find a way to reduce
this.
Thanks very much, I think I only do this for
just once. And after the thanslation is done, the performance is not turn to
normal. Does that mean that if I wait long enough it will recovery?
It almost certainly means you are not doing it just once like
you suppose.
~andrew
Yes, you are right. I added printk in
get_gfn and found it was call many times. I'll check why that happens.
Thanks a lot!
Sorry for mistaking it, the calls of these functions in log
appear before I invoke them. These functions that I invoked are through
hypercall in HVM DomU, through the log I think I invoked them only once. Maybe
the performance problem is caused by the parameters I used? Could you help me
the check if I used them unproperly as posted before.
Another question is when I add printk in paging_gva_to gfn
function, the performance alse down serioursly that it can't even boot hvm
domu successfully. I am wondering why.
Thanks again and best regards!
And after analyzing the performance of hvm domu, I found a
process named "evolution-data-" using almost 99.9% cpu. Does someone
known what's this and why it appears?
xinyue
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
