Set --seed per test
Set --seed per test

Summary:
This is done to avoid having each thread use the same seed between runs
of db_bench. Without this we can inflate the OS filesystem cache hit rate on
reads for read heavy tests and generally see the same key sequences get generated
between teste runs.

Task ID: #

Blame Rev:

Test Plan:
Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D37563

wlqGit/rocksdb,anagav/rocksdb,RyanTech/rocksdb,siddhartharay007/rocksdb,wlqGit/rocksdb,bbiao/rocksdb,ylong/rocksdb,kaschaeffer/rocksdb,norton/rocksdb,Andymic/rocksdb,JohnPJenkins/rocksdb,IMCG/RcoksDB,kaschaeffer/rocksdb,temicai/rocksdb,alihalabyah/rocksdb,zhangpng/rocksdb,RyanTech/rocksdb,JohnPJenkins/rocksdb,biddyweb/rocksdb,wenduo/rocksdb,ylong/rocksdb,facebook/rocksdb,tsheasha/rocksdb,siddhartharay007/rocksdb,zhangpng/rocksdb,wat-ze-hex/rocksdb,hobinyoon/rocksdb,Andymic/rocksdb,Applied-Duality/rocksdb,fengshao0907/rocksdb,JackLian/rocksdb,IMCG/RcoksDB,mbarbon/rocksdb,makelivedotnet/rocksdb,wenduo/rocksdb,makelivedotnet/rocksdb,rDSN-Projects/rocksdb.replicated,zhangpng/rocksdb,jalexanderqed/rocksdb,hobinyoon/rocksdb,wskplho/rocksdb,temicai/rocksdb,OverlordQ/rocksdb,anagav/rocksdb,bbiao/rocksdb,flabby/rocksdb,facebook/rocksdb,alihalabyah/rocksdb,mbarbon/rocksdb,JackLian/rocksdb,rDSN-Projects/rocksdb.replicated,dkorolev/rocksdb,anagav/rocksdb,JohnPJenkins/rocksdb,JackLian/rocksdb,hobinyoon/rocksdb,vmx/rocksdb,caijieming-baidu/rocksdb,Andymic/rocksdb,anagav/rocksdb,lgscofield/rocksdb,norton/rocksdb,vmx/rocksdb,sorphi/rocksdb,wlqGit/rocksdb,luckywhu/rocksdb,JoeWoo/rocksdb,SunguckLee/RocksDB,tsheasha/rocksdb,Andymic/rocksdb,OverlordQ/rocksdb,Andymic/rocksdb,caijieming-baidu/rocksdb,hobinyoon/rocksdb,kaschaeffer/rocksdb,luckywhu/rocksdb,tsheasha/rocksdb,tizzybec/rocksdb,mbarbon/rocksdb,JohnPJenkins/rocksdb,OverlordQ/rocksdb,makelivedotnet/rocksdb,JoeWoo/rocksdb,caijieming-baidu/rocksdb,vmx/rocksdb,SunguckLee/RocksDB,kaschaeffer/rocksdb,fengshao0907/rocksdb,NickCis/rocksdb,JackLian/rocksdb,geraldoandradee/rocksdb,norton/rocksdb,JackLian/rocksdb,vashstorm/rocksdb,ylong/rocksdb,mbarbon/rocksdb,vmx/rocksdb,Andymic/rocksdb,IMCG/RcoksDB,wat-ze-hex/rocksdb,alihalabyah/rocksdb,rDSN-Projects/rocksdb.replicated,skunkwerks/rocksdb,lgscofield/rocksdb,vashstorm/rocksdb,tizzybec/rocksdb,ylong/rocksdb,bbiao/rocksdb,norton/rocksdb,IMCG/RcoksDB,lgscofield/rocksdb,norton/rocksdb,caijieming-baidu/rocksdb,wat-ze-hex/rocksdb,NickCis/rocksdb,alihalabyah/rocksdb,OverlordQ/rocksdb,vmx/rocksdb,mbarbon/rocksdb,facebook/rocksdb,ylong/rocksdb,temicai/rocksdb,tsheasha/rocksdb,SunguckLee/RocksDB,biddyweb/rocksdb,NickCis/rocksdb,NickCis/rocksdb,jalexanderqed/rocksdb,jalexanderqed/rocksdb,biddyweb/rocksdb,sorphi/rocksdb,RyanTech/rocksdb,anagav/rocksdb,RyanTech/rocksdb,norton/rocksdb,rDSN-Projects/rocksdb.replicated,JoeWoo/rocksdb,siddhartharay007/rocksdb,tizzybec/rocksdb,flabby/rocksdb,Vaisman/rocksdb,vashstorm/rocksdb,Vaisman/rocksdb,skunkwerks/rocksdb,vmx/rocksdb,ryneli/rocksdb,JoeWoo/rocksdb,ylong/rocksdb,kaschaeffer/rocksdb,Vaisman/rocksdb,jalexanderqed/rocksdb,ryneli/rocksdb,biddyweb/rocksdb,IMCG/RcoksDB,biddyweb/rocksdb,NickCis/rocksdb,lgscofield/rocksdb,IMCG/RcoksDB,NickCis/rocksdb,SunguckLee/RocksDB,temicai/rocksdb,rDSN-Projects/rocksdb.replicated,tsheasha/rocksdb,facebook/rocksdb,tizzybec/rocksdb,ryneli/rocksdb,skunkwerks/rocksdb,Applied-Duality/rocksdb,anagav/rocksdb,Applied-Duality/rocksdb,tsheasha/rocksdb,biddyweb/rocksdb,IMCG/RcoksDB,vashstorm/rocksdb,flabby/rocksdb,rDSN-Projects/rocksdb.replicated,rDSN-Projects/rocksdb.replicated,facebook/rocksdb,bbiao/rocksdb,skunkwerks/rocksdb,alihalabyah/rocksdb,OverlordQ/rocksdb,wlqGit/rocksdb,jalexanderqed/rocksdb,wskplho/rocksdb,wat-ze-hex/rocksdb,wenduo/rocksdb,wskplho/rocksdb,Applied-Duality/rocksdb,geraldoandradee/rocksdb,wenduo/rocksdb,zhangpng/rocksdb,hobinyoon/rocksdb,wlqGit/rocksdb,tizzybec/rocksdb,hobinyoon/rocksdb,vashstorm/rocksdb,JohnPJenkins/rocksdb,hobinyoon/rocksdb,bbiao/rocksdb,bbiao/rocksdb,biddyweb/rocksdb,flabby/rocksdb,siddhartharay007/rocksdb,flabby/rocksdb,SunguckLee/RocksDB,ryneli/rocksdb,Applied-Duality/rocksdb,skunkwerks/rocksdb,wskplho/rocksdb,luckywhu/rocksdb,flabby/rocksdb,geraldoandradee/rocksdb,zhangpng/rocksdb,dkorolev/rocksdb,siddhartharay007/rocksdb,Andymic/rocksdb,SunguckLee/RocksDB,fengshao0907/rocksdb,caijieming-baidu/rocksdb,SunguckLee/RocksDB,hobinyoon/rocksdb,sorphi/rocksdb,tizzybec/rocksdb,dkorolev/rocksdb,bbiao/rocksdb,facebook/rocksdb,wskplho/rocksdb,tsheasha/rocksdb,norton/rocksdb,sorphi/rocksdb,Applied-Duality/rocksdb,jalexanderqed/rocksdb,facebook/rocksdb,fengshao0907/rocksdb,wenduo/rocksdb,Vaisman/rocksdb,wat-ze-hex/rocksdb,fengshao0907/rocksdb,wat-ze-hex/rocksdb,fengshao0907/rocksdb,bbiao/rocksdb,Applied-Duality/rocksdb,sorphi/rocksdb,tsheasha/rocksdb,RyanTech/rocksdb,skunkwerks/rocksdb,Andymic/rocksdb,OverlordQ/rocksdb,anagav/rocksdb,makelivedotnet/rocksdb,luckywhu/rocksdb,vmx/rocksdb,lgscofield/rocksdb,wlqGit/rocksdb,luckywhu/rocksdb,dkorolev/rocksdb,zhangpng/rocksdb,Vaisman/rocksdb,makelivedotnet/rocksdb,geraldoandradee/rocksdb,ryneli/rocksdb,siddhartharay007/rocksdb,JoeWoo/rocksdb,luckywhu/rocksdb,siddhartharay007/rocksdb,jalexanderqed/rocksdb,temicai/rocksdb,RyanTech/rocksdb,ylong/rocksdb,alihalabyah/rocksdb,NickCis/rocksdb,RyanTech/rocksdb,JoeWoo/rocksdb,mbarbon/rocksdb,vmx/rocksdb,ryneli/rocksdb,Vaisman/rocksdb,facebook/rocksdb,wlqGit/ro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