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Commit 021bff91 authored by Sarah Sharp's avatar Sarah Sharp Committed by Greg Kroah-Hartman
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USB: xhci: Performance - move functions that find ep ring. 



I've been using perf to measure the top symbols while transferring 1GB of data
on a USB 3.0 drive with dd.  This is using the raw disk with /dev/sdb, with a
block size of 1K.

During performance testing, the top symbol was xhci_triad_to_transfer_ring(), a
function that should return immediately if streams are not enabled for an
endpoint.  It turned out that the functions to find the endpoint ring was
defined in xhci-mem.c and used in xhci-ring.c and xhci-hcd.c.  I moved a copy of
xhci_triad_to_transfer_ring() and xhci_urb_to_transfer_ring() into xhci-ring.c
and declared them static.  I also made a static version of
xhci_urb_to_transfer_ring() in xhci.c.

This improved throughput on a 1GB read of the raw disk with dd from
186MB/s to 195MB/s, and perf reported sampling the xhci_triad_to_transfer_ring()
0.06% of the time, rather than 9.26% of the time.

Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent c6ba1c2a

drivers/usb/host/xhci-mem.c

+0 −43
Original line number Diff line number Diff line
@@ -391,49 +391,6 @@ struct xhci_ring *xhci_stream_id_to_ring( 
	return ep->stream_info->stream_rings[stream_id];

}



struct xhci_ring *xhci_triad_to_transfer_ring(struct xhci_hcd *xhci,

		unsigned int slot_id, unsigned int ep_index,

		unsigned int stream_id)

{

	struct xhci_virt_ep *ep;



	ep = &xhci->devs[slot_id]->eps[ep_index];

	/* Common case: no streams */

	if (!(ep->ep_state & EP_HAS_STREAMS))

		return ep->ring;



	if (stream_id == 0) {

		xhci_warn(xhci,

				"WARN: Slot ID %u, ep index %u has streams, "

				"but URB has no stream ID.\n",

				slot_id, ep_index);

		return NULL;

	}



	if (stream_id < ep->stream_info->num_streams)

		return ep->stream_info->stream_rings[stream_id];



	xhci_warn(xhci,

			"WARN: Slot ID %u, ep index %u has "

			"stream IDs 1 to %u allocated, "

			"but stream ID %u is requested.\n",

			slot_id, ep_index,

			ep->stream_info->num_streams - 1,

			stream_id);

	return NULL;

}



/* Get the right ring for the given URB.

 * If the endpoint supports streams, boundary check the URB's stream ID.

 * If the endpoint doesn't support streams, return the singular endpoint ring.

 */

struct xhci_ring *xhci_urb_to_transfer_ring(struct xhci_hcd *xhci,

		struct urb *urb)

{

	return xhci_triad_to_transfer_ring(xhci, urb->dev->slot_id,

		xhci_get_endpoint_index(&urb->ep->desc), urb->stream_id);

}



#ifdef CONFIG_USB_XHCI_HCD_DEBUGGING

static int xhci_test_radix_tree(struct xhci_hcd *xhci,

		unsigned int num_streams,

drivers/usb/host/xhci-ring.c

+44 −0
Original line number Diff line number Diff line
@@ -419,6 +419,50 @@ static struct xhci_segment *find_trb_seg( 
	return cur_seg;

}





static struct xhci_ring *xhci_triad_to_transfer_ring(struct xhci_hcd *xhci,

		unsigned int slot_id, unsigned int ep_index,

		unsigned int stream_id)

{

	struct xhci_virt_ep *ep;



	ep = &xhci->devs[slot_id]->eps[ep_index];

	/* Common case: no streams */

	if (!(ep->ep_state & EP_HAS_STREAMS))

		return ep->ring;



	if (stream_id == 0) {

		xhci_warn(xhci,

				"WARN: Slot ID %u, ep index %u has streams, "

				"but URB has no stream ID.\n",

				slot_id, ep_index);

		return NULL;

	}



	if (stream_id < ep->stream_info->num_streams)

		return ep->stream_info->stream_rings[stream_id];



	xhci_warn(xhci,

			"WARN: Slot ID %u, ep index %u has "

			"stream IDs 1 to %u allocated, "

			"but stream ID %u is requested.\n",

			slot_id, ep_index,

			ep->stream_info->num_streams - 1,

			stream_id);

	return NULL;

}



/* Get the right ring for the given URB.

 * If the endpoint supports streams, boundary check the URB's stream ID.

 * If the endpoint doesn't support streams, return the singular endpoint ring.

 */

static struct xhci_ring *xhci_urb_to_transfer_ring(struct xhci_hcd *xhci,

		struct urb *urb)

{

	return xhci_triad_to_transfer_ring(xhci, urb->dev->slot_id,

		xhci_get_endpoint_index(&urb->ep->desc), urb->stream_id);

}



/*

 * Move the xHC's endpoint ring dequeue pointer past cur_td.

 * Record the new state of the xHC's endpoint ring dequeue segment,

drivers/usb/host/xhci.c

+41 −0
Original line number Diff line number Diff line
@@ -916,6 +916,47 @@ dying: 
	return -ESHUTDOWN;

}



/* Get the right ring for the given URB.

 * If the endpoint supports streams, boundary check the URB's stream ID.

 * If the endpoint doesn't support streams, return the singular endpoint ring.

 */

static struct xhci_ring *xhci_urb_to_transfer_ring(struct xhci_hcd *xhci,

		struct urb *urb)

{

	unsigned int slot_id;

	unsigned int ep_index;

	unsigned int stream_id;

	struct xhci_virt_ep *ep;



	slot_id = urb->dev->slot_id;

	ep_index = xhci_get_endpoint_index(&urb->ep->desc);

	stream_id = urb->stream_id;

	ep = &xhci->devs[slot_id]->eps[ep_index];

	/* Common case: no streams */

	if (!(ep->ep_state & EP_HAS_STREAMS))

		return ep->ring;



	if (stream_id == 0) {

		xhci_warn(xhci,

				"WARN: Slot ID %u, ep index %u has streams, "

				"but URB has no stream ID.\n",

				slot_id, ep_index);

		return NULL;

	}



	if (stream_id < ep->stream_info->num_streams)

		return ep->stream_info->stream_rings[stream_id];



	xhci_warn(xhci,

			"WARN: Slot ID %u, ep index %u has "

			"stream IDs 1 to %u allocated, "

			"but stream ID %u is requested.\n",

			slot_id, ep_index,

			ep->stream_info->num_streams - 1,

			stream_id);

	return NULL;

}



/*

 * Remove the URB's TD from the endpoint ring.  This may cause the HC to stop

 * USB transfers, potentially stopping in the middle of a TRB buffer.  The HC

drivers/usb/host/xhci.h

+0 −5
Original line number Diff line number Diff line
@@ -1344,11 +1344,6 @@ void xhci_setup_no_streams_ep_input_ctx(struct xhci_hcd *xhci, 
struct xhci_ring *xhci_dma_to_transfer_ring(

		struct xhci_virt_ep *ep,

		u64 address);

struct xhci_ring *xhci_urb_to_transfer_ring(struct xhci_hcd *xhci,

		struct urb *urb);

struct xhci_ring *xhci_triad_to_transfer_ring(struct xhci_hcd *xhci,

		unsigned int slot_id, unsigned int ep_index,

		unsigned int stream_id);

struct xhci_ring *xhci_stream_id_to_ring(

		struct xhci_virt_device *dev,

		unsigned int ep_index,