Jürgen Keil <> wrote: >> I know that all USB host controllers interrupt *really* frequently. >> (1000Hz.) This is a flaw in the way those interfaces were designed. >> Its true when *any* device is plugged into the port, I believe. > > Maybe the usb host controllers access system memory that > frequently, but they don't interrupt 1000 times a second
Performance counter can help to check if CPU has memory access, but how to check memory access if it's caused by the DMA from USB host controller? If we don't see many interrupts from USB, can we say we don't have frequent DMA from USB host controller? > > (unless there is an usb device plugged in that really needs > to send 1000 interrupts per second). > Check with intrstat. intrstat can't help to shot. The interrupt number is the same on the problematic system and the normal system. Thanks, -Aubrey _______________________________________________ driver-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/driver-discuss
