[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] xen-unstable, winxp32 very poor performance on AMD FX-8150, I bisected and changeset is 24770:7f79475d3de7

On 17/01/13 20:57, Pasi Kärkkäinen wrote:

George: What do you think, should we add this bug to the Xen 4.3 status email 
for tracking it?
It's a serious HVM/winxp performance regression on AMD..

Hey Pasi -- thanks for bringing this thread to my attention. I had noticed a performance impact on AMD boxen myself, but investigating it had kind of gotten buried in more urgent tasks. Yes, I think we should track it. I'll put it on the list.


-- Pasi

On Sat, Jan 12, 2013 at 04:25:47PM +0100, Peter Maloney wrote:
On 11/22/2012 07:54 PM, Peter Maloney wrote:
On 11/13/2012 02:17 PM, Peter Maloney wrote:
On 2012-11-01 18:28, Andres Lagar-Cavilla wrote:
On Nov 1, 2012, at 1:00 PM, Tim Deegan <tim@xxxxxxx> wrote:


At 14:59 +0100 on 22 Oct (1350917960), Tim Deegan wrote:
At 19:21 +0200 on 20 Oct (1350760876), Peter Maloney wrote:
The change was 8 months ago

changeset:   24770:7f79475d3de7
user:        Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
date:        Fri Feb 10 16:07:07 2012 +0000
summary:     x86/mm: Make p2m lookups fully synchronized wrt modifications
Not any immediate ideas without profiling.

However, most callers of hvmemul_do_io pass a stub zero ram_gpa address. We 
might be madly hitting the p2m locks for no reason there.

How about the following patch, Peter, Tim?
I tried the patch applied to xen-unstable 4.2.0-branched
528f0708b6db+ 4.2.0-branched

It seemed the same. It was extremely slow with 7 vcpus, and with 2 vcpus
it was slow, but fast enough that I could bother to log in and out
during the test.

Attached are logs generated with this command (using xm instead of xl):
for i in {1..30}; do xm debug-keys d; xm dmesg -c; done >> nameoflog


Also there is xenxp_dmesg.log which is output from hitting alt+sysrq+w
and p in case it's relevant.

BTW this time I am testing with kernel 3.6.7

I also tested 4.2.1 now, and it has the same problem. And after using it
for a while with windows 8 (playing games), I get the general feel that
it is laggier than with 4.1.3. And now I'm using 4.1.4 which is fast
like 4.1.3.

So any ideas on how to fix this or gather more useful information?

Xen-devel mailing list

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.