From ac64995da872c8ae6f74a5556fdad565829985b0 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 11 Apr 2013 04:40:30 +0000 Subject: usbnet: introduce usbnet_link_change API This patch introduces the API of usbnet_link_change, so that usbnet can handle link change centrally, which may help to implement killing traffic URBs for saving USB bus bandwidth and host controller power. Signed-off-by: Ming Lei Signed-off-by: David S. Miller --- include/linux/usb/usbnet.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/usb/usbnet.h') diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h index 0e5ac93bab10..eb021b8f53bd 100644 --- a/include/linux/usb/usbnet.h +++ b/include/linux/usb/usbnet.h @@ -245,5 +245,6 @@ extern void usbnet_get_drvinfo(struct net_device *, struct ethtool_drvinfo *); extern int usbnet_nway_reset(struct net_device *net); extern int usbnet_manage_power(struct usbnet *, int); +extern void usbnet_link_change(struct usbnet *, bool, bool); #endif /* __LINUX_USB_USBNET_H */ -- cgit v1.2.3 From 4b49f58fff00e6e9b24eaa31d4c6324393d76b0a Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 11 Apr 2013 04:40:40 +0000 Subject: usbnet: handle link change The link change is detected via the interrupt pipe, and bulk pipes are responsible for transfering packets, so it is reasonable to stop bulk transfer after link is reported as off. Two adavantages may be obtained with stopping bulk transfer after link becomes off: - USB bus bandwidth is saved(USB bus is shared bus except for USB3.0), for example, lots of 'IN' token packets and 'NYET' handshake packets is transfered on 2.0 bus. - probabaly power might be saved for usb host controller since cancelling bulk transfer may disable the asynchronous schedule of host controller. With this patch, when link becomes off, about ~10% performance boost can be found on bulk transfer of anther usb device which is attached to same bus with the usbnet device, see below test on next-20130410: - read from usb mass storage(Sandisk Extreme USB 3.0) on pandaboard with below command after unplugging ethernet cable: dd if=/dev/sda iflag=direct of=/dev/null bs=1M count=800 - without the patch 1, 838860800 bytes (839 MB) copied, 36.2216 s, 23.2 MB/s 2, 838860800 bytes (839 MB) copied, 35.8368 s, 23.4 MB/s 3, 838860800 bytes (839 MB) copied, 35.823 s, 23.4 MB/s 4, 838860800 bytes (839 MB) copied, 35.937 s, 23.3 MB/s 5, 838860800 bytes (839 MB) copied, 35.7365 s, 23.5 MB/s average: 23.6MB/s - with the patch 1, 838860800 bytes (839 MB) copied, 32.3817 s, 25.9 MB/s 2, 838860800 bytes (839 MB) copied, 31.7389 s, 26.4 MB/s 3, 838860800 bytes (839 MB) copied, 32.438 s, 25.9 MB/s 4, 838860800 bytes (839 MB) copied, 32.5492 s, 25.8 MB/s 5, 838860800 bytes (839 MB) copied, 31.6178 s, 26.5 MB/s average: 26.1MB/s Signed-off-by: Ming Lei Signed-off-by: David S. Miller --- include/linux/usb/usbnet.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/usb/usbnet.h') diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h index eb021b8f53bd..da46327fca17 100644 --- a/include/linux/usb/usbnet.h +++ b/include/linux/usb/usbnet.h @@ -72,6 +72,7 @@ struct usbnet { # define EVENT_DEVICE_REPORT_IDLE 8 # define EVENT_NO_RUNTIME_PM 9 # define EVENT_RX_KILL 10 +# define EVENT_LINK_CHANGE 11 }; static inline struct usb_driver *driver_of(struct usb_interface *intf) -- cgit v1.2.3