How fast is the OHCI driver?
sebastian.huber at embedded-brains.de
Tue Mar 16 15:46:23 UTC 2010
I work with an ARM9 based system on a LPC3250 evaluation board from Phytec. It
has an integrated OHCI USB controller from NXP. The vendor provides a Linux
system for this board and with this system I can read with 1MByte/s from an USB
stick (I can also read with 23MByte/s from this stick on another system with an
EHCI controller). If I use the FreeBSD USB-stack (trunk revision 200101), then
I can only achieve a read performance of 70kByte/s. Comparing the activity on
the USB data lines with an oscilloscope of the two systems shows that on the
Linux system the line is continuously busy while on the FreeBSD based system
there are huge gaps of inactivity. Both systems operate with 12MHz. The
FreeBSD based system is 65% of the time in the idle task, so it seems that it
waits a lot for something.
Has someone values from other FreeBSD based systems with an OHCI controller?
Have a nice day!
Sebastian Huber, embedded brains GmbH
Address : Obere Lagerstr. 30, D-82178 Puchheim, Germany
Phone : +49 89 18 90 80 79-6
Fax : +49 89 18 90 80 79-9
E-Mail : sebastian.huber at embedded-brains.de
PGP : Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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