I tried USB 3.0 speed test with USB memory(HXS3 / 64GB).
(https://www.kingston.com/datasheets/hxs3_us.pdf)
When I connect usb memory through usb hub, it is faster than direct usb memory connection
I tested it several times, but the results did not change. The connection through the usb hub was always fast.
In general, I thought that if hubs were connected between usb and usb, the speed would drop.
What do you think about the unexpected result?
Connect usb memory directly to usb 3.0 on tx2 board.
root@tegra-ubuntu:/home/ubuntu# hdparm -t /dev/sda1
/dev/sda1:
Timing buffered disk reads: 574 MB in 3.00 seconds = 191.16 MB/sec
root@tegra-ubuntu:/home/ubuntu# lsusb -t
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci-tegra/3p, 5000M
|__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci-tegra/4p, 480M
Connect usb memory to usb3.0 of tx2 board through usb hub.
root@tegra-ubuntu:/home/ubuntu# hdparm -t /dev/sda1
/dev/sda1:
Timing buffered disk reads: 622 MB in 3.00 seconds = 207.32 MB/sec
root@tegra-ubuntu:/home/ubuntu# lsusb -t
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci-tegra/3p, 5000M
|__ Port 1: Dev 4, If 0, Class=Hub, Driver=hub/4p, 5000M
|__ Port 1: Dev 5, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci-tegra/4p, 480M
|__ Port 2: Dev 11, If 0, Class=Hub, Driver=hub/4p, 480M
Connect usb memory to usb3.0 of PC Main-board through usb hub.
root@ludishur-Ubuntu17:/media/ludishur/KINGSTON# hdparm -t /dev/sdf
/dev/sdf:
Timing buffered disk reads: 1262 MB in 3.00 seconds = 420.44 MB/sec
root@ludishur-Ubuntu17:/media/ludishur/KINGSTON# lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
|__ Port 5: Dev 26, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/14p, 480M
|__ Port 5: Dev 2, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M
|__ Port 5: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
Connect usb memory directly to usb 3.0 on PC Main-board.
root@ludishur-Ubuntu17:/media/ludishur/KINGSTON# hdparm -t /dev/sde1
/dev/sde1:
Timing buffered disk reads: 1250 MB in 3.00 seconds = 416.47 MB/sec
root@ludishur-Ubuntu17:/media/ludishur/KINGSTON# lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
|__ Port 5: Dev 27, If 0, Class=Hub, Driver=hub/4p, 5000M
|__ Port 2: Dev 28, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/14p, 480M
|__ Port 5: Dev 2, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M
|__ Port 5: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M