HDFS-16301. Improve BenchmarkThroughput#SIZE naming standardization. (#3622)

(cherry picked from commit b307f18a584b207782124bee0a377b2dbfc13df0)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/BenchmarkThroughput.java

@@ -190,7 +190,7 @@ public class BenchmarkThroughput extends Configured implements Tool {
     }
     Configuration conf = getConf();
     // the size of the file to write
-    long SIZE = conf.getLong("dfsthroughput.file.size",
+    long fileSize = conf.getLong("dfsthroughput.file.size",
         10L * 1024 * 1024 * 1024);
     BUFFER_SIZE = conf.getInt("dfsthroughput.buffer.size", 4 * 1024);
 
@@ -206,9 +206,9 @@ public class BenchmarkThroughput extends Configured implements Tool {
     ChecksumFileSystem checkedLocal = FileSystem.getLocal(conf);
     FileSystem rawLocal = checkedLocal.getRawFileSystem();
     for(int i=0; i < reps; ++i) {
-      writeAndReadLocalFile("local", conf, SIZE);
-      writeAndReadFile(rawLocal, "raw", conf, SIZE);
-      writeAndReadFile(checkedLocal, "checked", conf, SIZE);
+      writeAndReadLocalFile("local", conf, fileSize);
+      writeAndReadFile(rawLocal, "raw", conf, fileSize);
+      writeAndReadFile(checkedLocal, "checked", conf, fileSize);
     }
     MiniDFSCluster cluster = null;
     try {
@@ -217,7 +217,7 @@ public class BenchmarkThroughput extends Configured implements Tool {
       cluster.waitActive();
       FileSystem dfs = cluster.getFileSystem();
       for(int i=0; i < reps; ++i) {
-        writeAndReadFile(dfs, "dfs", conf, SIZE);
+        writeAndReadFile(dfs, "dfs", conf, fileSize);
       }
     } finally {
       if (cluster != null) {