On Wed, Sep 25, 2013 at 3:12 AM, Markus Rechberger <mrechberger@xxxxxxxxx> wrote: > This patch adds memory mapping support to USBFS for isochronous and bulk > data transfers, it allows to pre-allocate usb transfer buffers. > > The CPU usage decreases 1-2% on my 1.3ghz U7300 notebook when > transferring 20mbyte/sec, it should be more interesting to see those > statistics on embedded systems where copying data is more expensive. Given USB3 is becoming popular and throughput is increased much, zero copy should be charming. And another approach is to use direct I/O method(SG DMA to pages allocated to user space directly), which should be more flexible, and user don't need to use mmap/munmap, so should be easier to use. At least, wrt. usb mass storage test, both CPU utilization and throughput can be improved with direct I/O. Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
