| Message ID | 20230518204947.3770236-1-Frank.Li@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 2a1c4639d6d6bcee27f74e38f83ffb43579c4733 |
| Headers | show |
| Series | [1/2] usb: cdns3: improve handling of unaligned address case | expand |
On 23-05-18 16:49:45, Frank Li wrote: > When the address of a request was not aligned with an 8-byte boundary, the > USB DMA was unable to process it, necessitating the use of an internal > bounce buffer. > > In these cases, the request->buf had to be copied to/from this bounce > buffer. However, if this unaligned address scenario arises, it is > unnecessary to perform heavy cache maintenance operations like > usb_gadget_map(unmap)_request_by_dev() on the request->buf, as the DMA > does not utilize it at all. it can be skipped at this case. > > iperf3 tests on the rndis case: > > Transmit speed (TX): Improved from 299Mbps to 440Mbps > Receive speed (RX): Improved from 290Mbps to 500Mbps > > Signed-off-by: Frank Li <Frank.Li@nxp.com> > --- > drivers/usb/cdns3/cdns3-gadget.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c > index 1dcadef933e3..09a0882a4e97 100644 > --- a/drivers/usb/cdns3/cdns3-gadget.c > +++ b/drivers/usb/cdns3/cdns3-gadget.c > @@ -800,7 +800,8 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep, > if (request->status == -EINPROGRESS) > request->status = status; > > - usb_gadget_unmap_request_by_dev(priv_dev->sysdev, request, > + if (likely(!(priv_req->flags & REQUEST_UNALIGNED))) > + usb_gadget_unmap_request_by_dev(priv_dev->sysdev, request, > priv_ep->dir); > > if ((priv_req->flags & REQUEST_UNALIGNED) && > @@ -2543,10 +2544,12 @@ static int __cdns3_gadget_ep_queue(struct usb_ep *ep, > if (ret < 0) > return ret; > > - ret = usb_gadget_map_request_by_dev(priv_dev->sysdev, request, > + if (likely(!(priv_req->flags & REQUEST_UNALIGNED))) { > + ret = usb_gadget_map_request_by_dev(priv_dev->sysdev, request, > usb_endpoint_dir_in(ep->desc)); So, the possible reason for performance drop is do cache coherency operation twice for unaligned buffers? Peter > - if (ret) > - return ret; > + if (ret) > + return ret; > + } > > list_add_tail(&request->list, &priv_ep->deferred_req_list); > > -- > 2.34.1 >
diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c index 1dcadef933e3..09a0882a4e97 100644 --- a/drivers/usb/cdns3/cdns3-gadget.c +++ b/drivers/usb/cdns3/cdns3-gadget.c @@ -800,7 +800,8 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep, if (request->status == -EINPROGRESS) request->status = status; - usb_gadget_unmap_request_by_dev(priv_dev->sysdev, request, + if (likely(!(priv_req->flags & REQUEST_UNALIGNED))) + usb_gadget_unmap_request_by_dev(priv_dev->sysdev, request, priv_ep->dir); if ((priv_req->flags & REQUEST_UNALIGNED) && @@ -2543,10 +2544,12 @@ static int __cdns3_gadget_ep_queue(struct usb_ep *ep, if (ret < 0) return ret; - ret = usb_gadget_map_request_by_dev(priv_dev->sysdev, request, + if (likely(!(priv_req->flags & REQUEST_UNALIGNED))) { + ret = usb_gadget_map_request_by_dev(priv_dev->sysdev, request, usb_endpoint_dir_in(ep->desc)); - if (ret) - return ret; + if (ret) + return ret; + } list_add_tail(&request->list, &priv_ep->deferred_req_list);
When the address of a request was not aligned with an 8-byte boundary, the USB DMA was unable to process it, necessitating the use of an internal bounce buffer. In these cases, the request->buf had to be copied to/from this bounce buffer. However, if this unaligned address scenario arises, it is unnecessary to perform heavy cache maintenance operations like usb_gadget_map(unmap)_request_by_dev() on the request->buf, as the DMA does not utilize it at all. it can be skipped at this case. iperf3 tests on the rndis case: Transmit speed (TX): Improved from 299Mbps to 440Mbps Receive speed (RX): Improved from 290Mbps to 500Mbps Signed-off-by: Frank Li <Frank.Li@nxp.com> --- drivers/usb/cdns3/cdns3-gadget.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)