Re: [Xen-devel] Re: Poor performance on HVM (kernbench)

["Todd Deshane" <deshantm@xxxxxxxxx>]

On Thu, Sep 11, 2008 at 5:35 AM, George Dunlap
<George.Dunlap@xxxxxxxxxxxxx> wrote:
> On Wed, Sep 10, 2008 at 11:42 PM, Anthony Liguori <anthony@xxxxxxxxxxxxx> 
> wrote:
>>> Xen 3.3 should be an improvement with shadow3 right?
>>
>> I know it is for Windows, but there's always the possibility that it has
>> caused a regression in Linux performance.
>
> Shadow3 was definitely developed with Windows in mind.  Since it makes
> shadows act more like a hardware TLB, I'd expect it to perform better,
> or at least no worse; but since that's the biggest change with Xen HVM
> between 3.2 and 3.3, that's the first place I'd look.
>
> Todd,  would it be possible to send me a 30-second xentrace "sample"
> of kernbench running under 3.2 and 3.3?  The relevant command:
>
> xentrace -S 256 -e all /tmp/[filename].trace
>
> Set the kernbench run going in the guest, let it get going for about
> 30 seconds or so, and then start xentrace.  Let it run for 30 seconds,
> then kill it.  In 3.3, you can use the -T parameter to have it stop
> after 30 seconds; in 3.2, you can do something like:
>
> xentrace -S 256 -e all /tmp/[filename].trace & sleep 30 ; killall -INT 
> xentrace
>
> You can send me the files via something like http://yousendit.com.
>
> If you could possibly take a trace with a recent xen-unstable build,
> that would be even more helpful, since there are some key xentrace
> changes that make the information even more useful.
>

George: I sent both xen 3.2.1 and xen-unstable straces to you with the
service you suggested.

Let me know if you have any problems getting them.

If anyone else would like to see the traces, just let me know.

Cheers,
Todd

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