On Thu, 9 Apr 2015, Steve Bangert wrote: > > Still, I can imagine the uas-detect.h code setting the > > US_FL_MAX_SECTORS_64 flags bit and then the uas driver calling > > blk_queue_max_hw_sectors() the way we do in > > scsiglue.c:slave_configure(). > > Alan, would this approach create/implement dynamic max sector values > that might optimize speed/performance of the drive(s) transfer speeds? There already _is_ dynamic max_sector support in the kernel. Look at /sys/block/sdX/queue/max_sectors_kb (where X is the drive letter for your disk). I don't know how much additional performance you'll get out of it, but you can experiment with a few values. The disk drive probably will fail with any value much larger than 128, though -- try it and see. The problem is that you can't set this value before the disk is plugged in, and afterward it's already too late. That's why the initial value has to be set up by the driver. > The reason i ask is that the performance of the drive seems slow and > there were intermittent hangs during transfers based on my limited use > of the drive so far. Steve Does this happen with both the uas and usb-storage drivers or only with one of them? Alan Stern -- 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
