Small readSize in SmbFileInputStream.java results in very low read speed from SMB share.

[HubKing]

On my two Android devices, reading a file from an SMB share was very slow. The speed was about 0.3MB/s (the devices' Wi-Fi connection speed was 150Mbps). I checked the SMB packets on the Windows comptuer, and the read size was 4286.

A famous app called "Solid Explorer" is using this library, but showed faster copy speed (5MB/s). When I checked the SMB packets, its read size was set to 32768. The developers of Solid Explorer was using a modified version of JCIFS, and they had set a bigger read size.

When modified JCIFS just to set a bigger read size in , I could also achieve 5MB/s without modifying my app. I am not sure if this is a specific case of my devices or my Wi-Fi router, but please check if you could modify the library to use bigger read size when necessary.

[HubKing]

This seems to be because JCIFS does not support CAP_LARGE_READX.

For example, my Windows computer returned 4356 for "MaxBufferSize" and 65536 for "MaxRawSize" when negotiating. In the constructor, maxBufferSize is 4356 and smaller, so readSize is set to 4286.

    readSize = Math.min( file.tree.session.transport.rcv_buf_size - 70,
                        file.tree.session.transport.server.maxBufferSize - 70 );

In readDirect, readSize (4286) is used as the maxCount for SmbComReadAndX.

         r = len > readSize ? readSize : len;
        try {
               SmbComReadAndX request = new SmbComReadAndX( file.fid, fp, r, null );

Acocrding to MSDN, if the client sets CAP_LARGE_READX, the server can return more than the "MaxBufferSize" up to 65,535 bytes, which significantly increases the read speed.

[etemplar]

Hello, HubKing.

Does one need to do something except increasing readSize value?

In my case, len value is always ~8000, so readSize val does not really affect anything - r becomes equal to len in readDirect.

Download speed is fixed near 12-14 MBps/s. Some other apps show speed around 100 MBps/s (as it should be).

I've also tried to set properties in main application class' onCreate() without any success:

       System.setProperty("jcifs.resolveOrder", "DNS");
       System.setProperty("jcifs.smb.client.snd_buf_size", "60416");
       System.setProperty("jcifs.netbios.client.writeSize", "65535 ");

Any help is appreciated, thanks

[SteveGreatApe]

Try applying the patch in https://github.com/kohsuke/jcifs/blob/master/patches/LargeReadWrite.patch, it made a big difference for me.

[Techguyash]

Try applying the patch in https://github.com/kohsuke/jcifs/blob/master/patches/LargeReadWrite.patch, it made a big difference for me.

Hi SteveGreatApe,
Can you please help me how to apply the patch. I am using 1.3.14 jar. The upload size is very slow.