Copying file from external HDD causes high CPU load

[GoogleCodeExporter]

Hello,

using 3.0.3.6-064 on an RT-N65U with an external USB 2.0 HDD.

Copying a file from the HDD over network (samba share) causes high CPU load on 
the router (top output):

 917   715 nobody   R N   3168  2.5   0 61.9 /sbin/smbd -D -s /etc/smb.conf
  319     2 admin    SW       0  0.0   0 23.7 [usb-storage]

The transfer rate is about 24 MB/s (HDD can read faster if directly connected 
to my PC). I'm not sure if this is a regression in the latest version of if it 
always was like this.

Maybe you can improve this.

Original issue reported on code.google.com by xno...@gmail.com on 29 Jun 2013 at 7:29

[GoogleCodeExporter]

This is normal due to the weak CPU used in the router (500Mhz Clock Speed) and 
Samba is quite resource intensive when copying files. There's no real way to 
fix this unless you upgrade the router to something like the new RT-AC68U which 
features a Dual Core 1Ghz processor.

Original comment by c_u_late...@hotmail.com on 30 Jun 2013 at 6:23

[GoogleCodeExporter]

Use FTP, FTP less system overhead and max transfer rate ~38MB/s. SMB max 
transfer rate ~27MB/s. This is true when CPU not load by other tasks. 

Stock firmware N65U used LFP conntrack hack (LFP - Local Fast Path) for ports 
445 and 20 and kernel skip all conntrack for this local traffic. LFP increase 
USB performance +2MB/s for write and +5MB/s for read. I do not use LFP, this is 
a crude hack the Linux kernel.

Original comment by andy.pad...@gmail.com on 30 Jun 2013 at 12:21

[GoogleCodeExporter]

> FTP less system overhead and max transfer rate ~38MB/s. SMB max transfer rate 
~27MB/s

This is speed for USB3 drive. USB2 speed ~23-24 MB/s, FTP ~26-27 MB/s. 

Original comment by andy.pad...@gmail.com on 30 Jun 2013 at 12:25