buffer size update based on benchmark

README.md

@@ -7,6 +7,7 @@
 # Skbn
 
 Skbn is a tool for copying files and directories between Kubernetes and cloud storage providers. It is named after the 1981 video game [Sokoban](https://en.wikipedia.org/wiki/Sokoban).
+Skbn uses an in-memory buffer for the copy process, to avoid excessive memory consumption.
 Skbn currently supports the following providers:
 
 * AWS S3
@@ -77,7 +78,7 @@ skbn cp \
 ```
 * `n` is the number of files to be copied in parallel (for full parallelism use 0)
 
-### Set in memory buffer size
+### Set in-memory buffer size
 
 Skbn copies files using an in-memory buffer. To control the buffer size:
 
@@ -87,7 +88,8 @@ skbn cp \
     --dst ... \
     --buffer-size <f>
 ```
-* `f` is the in memory buffer size (in GB) to use for files copy. This flag should be used with caution when used in conjunction with `--parallel`
+* `f` is the in-memory buffer size (in MB) to use for files copy. This flag should be used with caution when used in conjunction with `--parallel`
+* The default value for `buffer-size` is 6.75 MB, and was decided based on benchmark
 
 ## Added bonus section
 

cmd/skbn.go

@@ -62,7 +62,7 @@ func NewCpCmd(out io.Writer) *cobra.Command {
 	f.StringVar(&c.src, "src", "", "path to copy from. Example: k8s://<namespace>/<podName>/<containerName>/path/to/copyfrom")
 	f.StringVar(&c.dst, "dst", "", "path to copy to. Example: s3://<bucketName>/path/to/copyto")
 	f.IntVarP(&c.parallel, "parallel", "p", 1, "number of files to copy in parallel. set this flag to 0 for full parallelism")
-	f.Float64VarP(&c.bufferSize, "buffer-size", "b", 1, "in memory buffer size (GB) to use for files copy (buffer per file)")
+	f.Float64VarP(&c.bufferSize, "buffer-size", "b", 6.75, "in memory buffer size (MB) to use for files copy (buffer per file)")
 
 	cmd.MarkFlagRequired("src")
 	cmd.MarkFlagRequired("dst")

pkg/skbn/skbn.go

@@ -120,7 +120,7 @@ func PerformCopy(srcClient, dstClient interface{}, srcPrefix, dstPrefix string,
 
 		go func(srcClient, dstClient interface{}, srcPrefix, fromPath, dstPrefix, toPath, currentLinePadded string, totalFiles int) {
 
-			newBufferSize := (int64)(bufferSize * 1024 * 1024 * 1024) // may not be super accurate
+			newBufferSize := (int64)(bufferSize * 1024 * 1024) // may not be super accurate
 			buf := buffer.New(newBufferSize)
 			pr, pw := nio.Pipe(buf)