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MUSB performance

Question asked by fschmid on Jun 7, 2012
Latest reply on Jun 15, 2012 by Aaronwu



I'm trying to evaluate the USB device performance on a BF527-ezkit. I tried the loopback example from the VDSP installation (Blackfin\Examples\ADSP-BF527 EZ-KIT Lite\Drivers\usb\bulk_loopback_app). I ran it on a Windows XP laptop with the supplied hostapp.exe application. My results are included below:


Running loopback on Blackfin USB #0 (ADSP-BF527)


Running time:      0 days 0 hrs 0 mins 10 secs

Transfer size:     65536 Bytes

Total loops:       627

Total data looped: 39.19 MBytes

Avg loopback rate: 3.60 MBytes/sec

Data error count:  0


                           LAST AVERAGE    AVERAGE     MAX     MIN

LAST 100


OUT - from host (MB/s):   07.48 07.43      07.43     07.65   07.01

IN  - to host   (MB/s):   20.67 20.66      20.86     23.25   18.71

Timestamps:               Out Max: 00:00:00:00   Out Min: 00:00:00:10

                          In Max:  00:00:00:00   In Min:  00:00:00:08


From the readme.txt in the same folder, the indicated performance is:


                           LAST AVERAGE    AVERAGE     MAX     MIN

LAST 100


OUT - from host (MB/s):   28.69 28.26      28.13     29.84   15.09

IN  - to host   (MB/s):   38.19 37.56      36.99     40.08   08.13

Timestamps:               Out Max: 00:00:00:01   Out Min: 00:00:00:00

                          In Max:  00:00:00:03   In Min:  00:00:00:01


My results seem pretty far from those. What is needed to reach those numbers?


I also ran some tests on the gadget driver, g_zero, in uClinux. Bandwidth seems to peak between 15-16MB/s. Actually the real target platform is uClinux and our bandwidth requirement for a gadget-driver  is around 20MB/s. Do you think this is possible on uClinux? If so, why or why not?


Best regards,