The Read Test

##Introduction This benchmark is to test the read performance of Tachyon. It will setup a set of TachyonFS and read data from Tachyon concurrently.

When running, each node starts several threads and each thread contains a Tachyon client. The client will read a list of files from the node's workspace. Note that each node has its own workspace so that the threads of different nodes will not read the same file.

There are several read modes for users to select. The two key parameters are mode and identical. The thread will read the files randomly if mode is "RANDOM" or read the files sequently if mode is "SEQUENCE". And if identical is "true", all the threads of a node will read the same files.

##Configuration The configurations of this benchmark is in conf/testSuite/Read.xml.

Property Name	Meaning	Default Value
threads.num	the threads num of read test	4
files.per.thread	the number of files to read for each read thread	6
mode	the read mode of read test, should be RANDOM or SEQUENCE	RANDOM
identical	if true, all the read threads will read the same files	false
grain.bytes	the size of the buffer which is read from Tachyon once	4194304
read.type	the ReadType of the read operation	CACHE

##Result Demo This benchmark is supported to generate a total report by the tool TachyonPerfCollector. After finished a Read Test, you can generate a total report with the command ./bin/tachyon-perf-collect Read. Here is a demo of the total report:

Read Test - ID : 1409646341296
Finished Successfully
********** System Configuratiom **********
NodeName	Cores	WorkerMemory
localhost	16	6.0GB
Total	16	6.0GB
********** Read Test Settings **********
tachyon.perf.tfs.address	tachyon://localhost:19998
files.per.thread	6
grain.bytes	4194304
identical	false
mode	RANDOM
threads.num	4
READ_TYPE	CACHE
********** Read Throughput **********
NodeName	ReadThroughput(MB/s)
localhost	141.70792
Total	141.70792
********** Node Details **********
localhost's throughput(MB/s) for each threads:
	[ 33.21081 ][ 35.91806 ][ 34.20783 ][ 38.371223 ]

In the total report, it will list the related system environment, the configurations and the performance result. In the Read Test, we focus on the read throughput and we show the result in MB/s.