Re: [Xen-devel] [PATCH RFC V8 0/17] Paravirtualized ticket spinlocks

[Avi Kivity <avi@xxxxxxxxxx>]

On 05/07/2012 01:58 PM, Raghavendra K T wrote:
> On 05/07/2012 02:02 PM, Avi Kivity wrote:
>> On 05/07/2012 11:29 AM, Ingo Molnar wrote:
>>> This is looking pretty good and complete now - any objections
>>> from anyone to trying this out in a separate x86 topic tree?
>>
>> No objections, instead an
>>
>> Acked-by: Avi Kivity<avi@xxxxxxxxxx>
>>
>
> Thank you.
>
> Here is a benchmark result with the patches.
>
> 3 guests with 8VCPU, 8GB RAM, 1 used for kernbench
> (kernbench -f -H -M -o 20) other for cpuhog (shell script while
> true with an instruction)
>
> unpinned scenario
> 1x: no hogs
> 2x: 8hogs in one guest
> 3x: 8hogs each in two guest
>
> BASE: 3.4-rc4 vanilla with CONFIG_PARAVIRT_SPINLOCK=n
> BASE+patch: 3.4-rc4 + debugfs + pv patches with
> CONFIG_PARAVIRT_SPINLOCK=y
>
> Machine : IBM xSeries with Intel(R) Xeon(R) x5570 2.93GHz CPU (Non
> PLE) with 8 core , 64GB RAM
>
> (Less is better. Below is time elapsed in sec for x86_64_defconfig
> (3+3 runs)).
>
>          BASE                    BASE+patch            %improvement
>          mean (sd)               mean (sd)
> case 1x:     66.0566 (74.0304)      61.3233 (68.8299)     7.16552
> case 2x:     1253.2 (1795.74)      131.606 (137.358)     89.4984
> case 3x:     3431.04 (5297.26)      134.964 (149.861)     96.0664
>

You're calculating the improvement incorrectly.  In the last case, it's
not 96%, rather it's 2400% (25x).  Similarly the second case is about
900% faster.

-- 
error compiling committee.c: too many arguments to function


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