Socket programming in android - Reading bytes from input stream is very slow over Wifi

Question

I am using Sockets for transferring data over Wifi in my android app, I have set the Buffer size to around 10MB and here is my code for sending data.

// Sending data from a file in chunks, PREFERRED_CHUNK_SIZE is [1024 * 1024 * 10]

var fileSize = fileList[index].totalSize
val buffer = ByteArray(SocketConstants.PREFERRED_CHUNK_SIZE)
var length: Int
do {
    length = stream.read(buffer, 0, min(buffer.size, fileSize))
    bos.write(buffer, 0, length)
    fileSize -= length
} while (fileSize != 0)
 stream.close()

I am reusing the same code for multiple file transfer, the condition filesize,= 0 makes sure I read only that much bytes for a single file and thus I have used that min function lets say I want to send 36 MB it is sent as 10(10485760 bytes), 10(10485760 bytes), 10(10,485,760 bytes). 6.

Below is my code for receiver:

        var fileSize = file.totalSize
        var current: Int
        var offset = 0
        val byteArray = ByteArray(SocketConstants.PREFERRED_CHUNK_SIZE)
        val bufferedInputStream = BufferedInputStream(inputStream)
        do {
            current = bufferedInputStream.read(byteArray, 0, min(byteArray.size, fileSize))
//            outputStream.write(byteArray, 0, current)  To ignore file write for now
            fileSize -= current
            offset += current
            println("Length: $current")
            file.bytesDownloaded = offset
            updateList(offset)
        } while (fileSize != 0)
        outputStream.flush()
        outputStream.close()

When reading I am getting really small chunks of bytes, 1358, 1358, 1358, 1358, 1358.

This is really slow, I don't understand what is causing inputStream.read() such small reads.

I have already set the sender and receiver buffer size for SocketServer and Socket instance. But there was no difference in the results

Answer 1

After looking for a solution for few days and trying multiple ways to increase the speed when read is called on inputstream I finally discovered the solution.

Thanks Gerd in comments who kind of helped me start thinking about the strength of a Wifi connection.

What I found was, if you connect to wifi using Android Wifi Manager, the connection established is a slow connection and you wouldn't even see in the task bar if you are connected to an actual wifi.

To overcome it, I manually connected to hotspot using Wifi settings in the mobile and that has better speed.