Re: [PATCH RFC V10 0/18] Paravirtualized ticket spinlocks

[Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>]

On 06/24/2013 06:47 PM, Andrew Jones wrote:
> On Mon, Jun 24, 2013 at 06:10:14PM +0530, Raghavendra K T wrote:
>>
>> Results:
>> =======
>> base = 3.10-rc2 kernel
>> patched = base + this series
>>
>> The test was on 32 core (model: Intel(R) Xeon(R) CPU X7560) HT disabled
>> with 32 KVM guest vcpu 8GB RAM.
>
> Have you ever tried to get results with HT enabled?
>
>>
>> +-----------+-----------+-----------+------------+-----------+
>>                 ebizzy (records/sec) higher is better
>> +-----------+-----------+-----------+------------+-----------+
>>      base        stdev        patched    stdev        %improvement
>> +-----------+-----------+-----------+------------+-----------+
>> 1x  5574.9000   237.4997    5618.0000    94.0366     0.77311
>> 2x  2741.5000   561.3090    3332.0000   102.4738    21.53930
>> 3x  2146.2500   216.7718    2302.3333    76.3870     7.27237
>> 4x  1663.0000   141.9235    1753.7500    83.5220     5.45701
>> +-----------+-----------+-----------+------------+-----------+
>
> This looks good. Are your ebizzy results consistent run to run
> though?
>
>> +-----------+-----------+-----------+------------+-----------+
>>                dbench  (Throughput) higher is better
>> +-----------+-----------+-----------+------------+-----------+
>>      base        stdev        patched    stdev        %improvement
>> +-----------+-----------+-----------+------------+-----------+
>> 1x 14111.5600   754.4525   14645.9900   114.3087     3.78718
>> 2x  2481.6270    71.2665    2667.1280    73.8193     7.47498
>> 3x  1510.2483    31.8634    1503.8792    36.0777    -0.42173
>> 4x  1029.4875    16.9166    1039.7069    43.8840     0.99267
>> +-----------+-----------+-----------+------------+-----------+
>
> Hmm, I wonder what 2.5x looks like. Also, the 3% improvement with
> no overcommit is interesting. What's happening there? It makes
> me wonder what < 1x looks like.
>

Hi Andrew,

I tried 2.5x case sort where I used 3 guests with 27 vcpu each on 32
core (HT disabled machine) and here is the output. almost no gain there.

              throughput avg    stdev
base:     1768.7458 MB/sec     54.044221
patched:  1772.5617 MB/sec     41.227689
gain %0.226

I am yet to try HT enabled cases that would give 0.5x to 2x performance
results.