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: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-mem.c | 43 -----------------------------------------
drivers/usb/host/xhci-ring.c | 44 ++++++++++++++++++++++++++++++++++++++++++
drivers/usb/host/xhci.c | 41 +++++++++++++++++++++++++++++++++++++++
drivers/usb/host/xhci.h | 5 ----
4 files changed, 85 insertions(+), 48 deletions(-)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index af0514f..2908700 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -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,
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index da3519e..7f1c545 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -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,
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 51dc2cb..a8d483f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -918,6 +918,47 @@ 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
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index e1383d9..9fe95c4 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -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,
--
1.6.3.3
--
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