update spark.default.parallelism
update spark.default.parallelism

actually, the value 8 is only valid in mesos fine-grained mode :
<code>
  override def defaultParallelism() = sc.conf.getInt("spark.default.parallelism", 8)
</code>

while in coarse-grained model including mesos coares-grained, the value of the property depending on core numbers!
<code>
override def defaultParallelism(): Int = {
   conf.getInt("spark.default.parallelism", math.max(totalCoreCount.get(), 2))
  }
</code>

Author: Chen Chao <crazyjvm@gmail.com>

Closes #389 from CrazyJvm/patch-2 and squashes the following commits:

84a7fe4 [Chen Chao] miss </li> at the end of every single line
04a9796 [Chen Chao] change format
ee0fae0 [Chen Chao] update spark.default.parallelism

SnappyDataInc/spark,sachintyagi22/spark,pgandhi999/spark,SHASHANKB/spark,nchammas/spark,mzl9039/spark,bdrillard/spark,goldmedal/spark,publicRoman/spark,rednaxelafx/apache-spark,SHASHANKB/spark,ueshin/apache-spark,shaneknapp/spark,lvdongr/spark,jianran/spark,poffuomo/spark,haowu80s/spark,eyalfa/spark,rezasafi/spark,mzl9039/spark,bravo-zhang/spark,kissmetrics/spark,JerryLead/spark,zzcclp/spark,rezasafi/spark,cloud-fan/spark,tejasapatil/spark,highfei2011/spark,apache-spark-on-k8s/spark,mdespriee/spark,aosagie/spark,vinodkc/spark,maropu/spark,saturday-shi/spark,WeichenXu123/spark,byakuinss/spark,Panos-Bletsos/spark-cost-model-optimizer,nilsgrabbert/spark,wzhfy/spark,ueshin/apache-spark,poffuomo/spark,jiangxb1987/spark,mahak/spark,jlopezmalla/spark,spark-test/spark,adrian-ionescu/apache-spark,lxsmnv/spark,wzhfy/spark,lvdongr/spark,skonto/spark,saltstar/spark,jianran/spark,dongjoon-hyun/spark,goldmedal/spark,janewangfb/spark,sahilTakiar/spark,jlopezmalla/spark,nchammas/spark,szhem/spark,bravo-zhang/spark,aosagie/spark,hhbyyh/spark,byakuinss/spark,mzl9039/spark,matthewfranglen/spark,mahak/spark,actuaryzhang/spark,sachintyagi22/spark,zero323/spark,big-pegasus/spark,skonto/spark,huang1900/spark,ericvandenbergfb/spark,aray/spark,zuotingbing/spark,ptkool/spark,aosagie/spark,icexelloss/spark,caneGuy/spark,narahari92/spark,pgandhi999/spark,icexelloss/spark,wzhfy/spark,zero323/spark,akopich/spark,liutang123/spark,kissmetrics/spark,ron8hu/spark,jiangxb1987/spark,shaneknapp/spark,aray/spark,milliman/spark,zhouyejoe/spark,ddna1021/spark,caneGuy/spark,BryanCutler/spark,taroplus/spark,holdenk/spark,huang1900/spark,kevinyu98/spark,gengliangwang/spark,poffuomo/spark,shaneknapp/spark,narahari92/spark,debugger87/spark,JoshRosen/spark,loneknightpy/spark,WindCanDie/spark,milliman/spark,shaneknapp/spark,LantaoJin/spark,tengpeng/spark,JerryLead/spark,gengliangwang/spark,guoxiaolongzte/spark,hvanhovell/spark,ueshin/apache-spark,shubhamchopra/spark,michalsenkyr/spark,map222/spark,setjet/spark,hvanhovell/spark,skonto/spark,ConeyLiu/spark,darionyaphet/spark,facaiy/spark,ron8hu/spark,eyalfa/spark,haowu80s/spark,patrick-nicholson/spark,mdespriee/spark,chuckchen/spark,markhamstra/spark,wzhfy/spark,gengliangwang/spark,huang1900/spark,pgandhi999/spark,apache-spark-on-k8s/spark,holdenk/spark,brad-kaiser/spark,techaddict/spark,kiszk/spark,ConeyLiu/spark,icexelloss/spark,kevinyu98/spark,jlopezmalla/spark,ahnqirage/spark,witgo/spark,map222/spark,tengpeng/spark,bOOm-X/spark,narahari92/spark,nilsgrabbert/spark,nlalevee/spark,HyukjinKwon/spark,ibm-research-ireland/sparkoscope,ericvandenbergfb/spark,lxsmnv/spark,ibm-research-ireland/sparkoscope,srowen/spark,cloud-fan/spark,byakuinss/spark,tengpeng/spark,zzcclp/spark,aokolnychyi/spark,facaiy/spark,loneknightpy/spark,hvanhovell/spark,tejasapatil/spark,ron8hu/spark,guoxiaolongzte/spark,SHASHANKB/spark,nchammas/spark,techaddict/spark,JoshRosen/spark,big-pegasus/spark,rezasafi/spark,apache/spark,pronix/spark,setjet/spark,lvdongr/spark,taroplus/spark,SnappyDataInc/spark,ioana-delaney/spark,aokolnychyi/spark,ddna1021/spark,adrian-ionescu/apache-spark,LantaoJin/spark,jrshust/spark,metamx/spark,sachintyagi22/spark,jlopezmalla/spark,aray/spark,patrick-nicholson/spark,bdrillard/spark,cin/spark,vinodkc/spark,apache-spark-on-k8s/spark,zzcclp/spark,tengpeng/spark,jrshust/spark,vinodkc/spark,mdespriee/spark,kimoonkim/spark,yanboliang/spark,ioana-delaney/spark,dbtsai/spark,HyukjinKwon/spark,LantaoJin/spark,bdrillard/spark,metamx/spark,andrewor14/spark,WeichenXu123/spark,loneknightpy/spark,xflin/spark,milliman/spark,metamx/spark,hhbyyh/spark,zuotingbing/spark,map222/spark,minixalpha/spark,wangmiao1981/spark,ConeyLiu/spark,markhamstra/spark,zero323/spark,sachintyagi22/spark,xuanyuanking/spark,WindCanDie/spark,joseph-torres/spark,shaneknapp/spark,jiangxb1987/spark,michalsenkyr/spark,andrewor14/spark,stanzhai/spark,narahari92/spark,WindCanDie/spark,jianran/spark,JoshRosen/spark,loneknightpy/spark,bravo-zhang/spark,spark-test/spark,nilsgrabbert/spark,jiangxb1987/spark,UndeadBaneGitHub/spark,taroplus/spark,ahnqirage/spark,poffuomo/spark,rekhajoshm/spark,bravo-zhang/spark,andrewor14/iolap,debugger87/spark,zuotingbing/spark,ahnqirage/spark,xuanyuanking/spark,setjet/spark,apache/spark,tejasapatil/spark,joseph-torres/spark,JoshRosen/spark,MLnick/spark,kissmetrics/spark,setjet/spark,BryanCutler/spark,ueshin/apache-spark,alunarbeach/spark,dhruve/spark,janewangfb/spark,kevinyu98/spark,alunarbeach/spark,rednaxelafx/apache-spark,actuaryzhang/spark,shuangshuangwang/spark,zhouyejoe/spark,liutang123/spark,apache-spark-on-k8s/spark,chuckchen/spark,narahari92/spark,maropu/spark,saturday-shi/spark,szhem/spark,hvanhovell/spark,kevinyu98/spark,apache/spark,nilsgrabbert/spark,liutang123/spark,ddna1021/spark,sahilTakiar/spark,UndeadBaneGitHub/spark,debugger87/spark,bOOm-X/spark,stanzhai/spark,cloud-fan/spark,rekhajoshm/spark,szhem/spark,WindCanDie/spark,byakuinss/spark,minixalpha/spark,holdenk/spark,debugger87/spark,saltstar/spark,joseph-to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