Hi,
I have a linux system with two GPIB interfaces on it, an old PCI-GPIB (rev 01) and a brand-new USB-HS. Running a test code that communicates with a well-tested GPIB instrument (a CAMAC crate controller) shows that the old PCI board is 10 times faster than the USB-HS for a simple repeated write operation. The system
does support USB2; diagnostics do not return any errors for either interface.
Details:
up-to-date gentoo box, 2.6.19-gentoo-r5 kernel
c code, gcc 4.1.1 compiler. Relevant code is:
for(i = 0; i < count; i++)
{
data[3]=i%256; data[4]=(i/256)%256; data[5]=i/(256*256)%256;
ibwrt(cc12,data,6); /*typical camac write data*/
}
tend();
t = tval();
printf("%d calls to tend() = %2.6f seconds\n",(int)count,t);
a few lines of dmesg output:
ehci_hcd 0000:00:02.2: new USB bus registered, assigned bus number 1
ehci_hcd 0000:00:02.2: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004
hub 1-0:1.0: USB hub found
Initializing USB Mass Storage driver...
usb 1-3: new high speed USB device using ehci_hcd and address 3
USB Mass Storage support registered.
USB Universal Host Controller Interface driver v3.0
ohci_hcd: 2006 August 04 USB 1.1 'Open' Host Controller (OHCI) Driver (PCI)
ohci_hcd 0000:00:02.0: new USB bus registered, assigned bus number 2
hub 2-0:1.0: USB hub found
ohci_hcd 0000:00:02.1: new USB bus registered, assigned bus number 3
hub 3-0:1.0: USB hub found
...
Symbol usb_register_driver is being used by a non-GPL module, which will not be allowed in the future
Please see the file Documentation/feature-removal-schedule.txt in the kernel source tree for more details.
Symbol usb_deregister is being used by a non-GPL module, which will not be allowed in the future
Please see the file Documentation/feature-removal-schedule.txt in the kernel source tree for more details.
nipalk: no version for "nNIKAL100_getTimeOfDayInterval" found: kernel tainted.
ACPI: PCI Interrupt 0000:01:04.0[A] -> Link [APC1] -> GSI 16 (level, high) -> IRQ 20
usbcore: registered new interface driver ni488
