Storage Speed on the PandaBoard Revisited

A recent thread on the Fedora arm mailing list had me revisit the storage speed tests I ran recently.  DJ Delorie found that his USB storage speed more than doubled if he pinged the PandaBoard from another host.  The PandaBoard's ethernet is part of the USB smsc95xx chipset, so it makes sense that they're related.

With that in mind, I ran the bonnie++ tests again while pinging the PandaBoard (from the same system running minicom to access the serial console of the PandaBoard). The first row is copied-and-pasted from the last test. The second row holds the new results.

Version 1.96

Sequential Output

Sequential Input

Random Seeks

Size

Per Char

Block

Rewrite

Per Char

Block

K/sec

% CPU

K/sec

% CPU

K/sec

% CPU

K/sec

% CPU

K/sec

% CPU

/sec

% CPU

USB HD

2G

43

99

9017

16

4538

6

369

99

12357

9

93.9

6

Latency

215ms

5849ms

5889ms

52858us

108ms

7643ms

USB HD with ping

2G

38

99

19038

39

9709

14

364

99

24947

21

162.7

11

Latency

220ms

1714ms

1319ms

62165us

16327us

1542ms

That's amazing!  Sequential Writes more than doubled: from 9017 K/sec to 19038 K/sec.  And Sequential Reads doubled: from 12357 K/sec to 24947 K/sec!

There seems to be a bug somewhere, maybe in the smsc95xx driver?  If this can be fixed, using a USB hard drive could greatly improve the storage speeds on the PandaBoard.