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Message-ID: <CAPybu_10kUFE02QewKd7Lf3CVrJa5y4ogPfptViUfWzTh0W_qg@mail.gmail.com>
Date: Fri, 26 Nov 2021 17:37:32 +0100
From: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
To: Kyeongdon Kim <kyeongdon.kim@....com>
Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
linux-media <linux-media@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Ricardo Ribalda <ribalda@...omium.org>
Subject: Re: [PATCH v2] media: uvcvideo: use dynamic allocation for uvc_copy_op
Hi Kyeongdon
I fail to understand why your approach is faster than the original one.
Is it because of the alignment of struct uvc_copy_op copy_operations ?
Thanks!
On Fri, Sep 3, 2021 at 6:56 AM Kyeongdon Kim <kyeongdon.kim@....com> wrote:
>
> There are some issues to handle frame throughput with camera devices
>
> Using devices:
> - Logitech Webcam
> - Intel(R) RealSense(TM) Depth Camera
>
> To improve efficiency, and maximise throughput,
> use dynamic allocation for uvc_copy_op.
>
> Change from struct uvc_copy_op copy_operations[UVC_MAX_PACKETS];
> to struct uvc_copy_op *copy_operations;
>
> Now, only tested bulk video options.
>
> On test device & own debug log to check frame duration(us),
> refer to test result the below:
>
> Use copy_operations[UVC_MAX_PACKETS]
> [UVC] Check time duration(us) : 54732 / 66000
> [UVC] Check time duration(us) : 57452 / 66000
> [UVC] Check time duration(us) : 57413 / 66000
> [UVC] Check time duration(us) : 56713 / 66000
> [UVC] Check time duration(us) : 57967 / 66000
>
> Use *copy_operations
> [UVC] Check time duration(us) : 30804 / 66000
> [UVC] Check time duration(us) : 38642 / 66000
> [UVC] Check time duration(us) : 26011 / 66000
> [UVC] Check time duration(us) : 30116 / 66000
> [UVC] Check time duration(us) : 29265 / 66000
>
> Signed-off-by: Kyeongdon Kim <kyeongdon.kim@....com>
> ---
> drivers/media/usb/uvc/uvc_video.c | 55 ++++++++++++++++++++++++++++++++++++---
> drivers/media/usb/uvc/uvcvideo.h | 3 ++-
> 2 files changed, 54 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index e164646..3a7c131 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -1614,6 +1614,36 @@ static void uvc_video_complete(struct urb *urb)
> queue_work(stream->async_wq, &uvc_urb->work);
> }
>
> +static void uvc_free_urb_cop(struct uvc_streaming *stream)
> +{
> + struct uvc_urb *uvc_urb;
> +
> + for_each_uvc_urb(uvc_urb, stream) {
> + if (uvc_urb->copy_operations) {
> + kfree(uvc_urb->copy_operations);
> + uvc_urb->copy_operations = NULL;
> + }
> + }
> +}
> +
> +static int uvc_alloc_urb_cop(struct uvc_streaming *stream, gfp_t gfp_flags)
> +{
> + int max_packet = stream->urb_max_packets;
> + struct uvc_urb *uvc_urb;
> +
> + for_each_uvc_urb(uvc_urb, stream) {
> + uvc_urb->copy_operations
> + = kcalloc(max_packet, sizeof(struct uvc_copy_op), gfp_flags);
> + if (uvc_urb->copy_operations == NULL)
> + goto error;
> + }
> + return 0;
> +error:
> + uvc_free_urb_cop(stream);
> +
> + return -ENOMEM;
> +}
> +
> /*
> * Free transfer buffers.
> */
> @@ -1687,8 +1717,8 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
> * payloads across multiple URBs.
> */
> npackets = DIV_ROUND_UP(size, psize);
> - if (npackets > UVC_MAX_PACKETS)
> - npackets = UVC_MAX_PACKETS;
> + if (npackets > stream->urb_max_packets)
> + npackets = stream->urb_max_packets;
>
> /* Retry allocations until one succeed. */
> for (; npackets > 1; npackets /= 2) {
> @@ -1744,8 +1774,10 @@ static void uvc_video_stop_transfer(struct uvc_streaming *stream,
> uvc_urb->urb = NULL;
> }
>
> - if (free_buffers)
> + if (free_buffers) {
> uvc_free_urb_buffers(stream);
> + uvc_free_urb_cop(stream);
> + }
> }
>
> /*
> @@ -1790,10 +1822,18 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream,
> psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
> size = stream->ctrl.dwMaxVideoFrameSize;
>
> + stream->urb_max_packets = UVC_MAX_PACKETS;
> +
> npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
> if (npackets == 0)
> return -ENOMEM;
>
> + if (uvc_alloc_urb_cop(stream, gfp_flags) != 0) {
> + uvc_dbg(stream->dev, VIDEO,
> + "Failed to init URBs copy operations.\n");
> + return -ENOMEM;
> + }
> +
> size = npackets * psize;
>
> for_each_uvc_urb(uvc_urb, stream) {
> @@ -1842,11 +1882,18 @@ static int uvc_init_video_bulk(struct uvc_streaming *stream,
> psize = usb_endpoint_maxp(&ep->desc);
> size = stream->ctrl.dwMaxPayloadTransferSize;
> stream->bulk.max_payload_size = size;
> + stream->urb_max_packets = DIV_ROUND_UP(size, psize);
>
> npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
> if (npackets == 0)
> return -ENOMEM;
>
> + if (uvc_alloc_urb_cop(stream, gfp_flags) != 0) {
> + uvc_dbg(stream->dev, VIDEO,
> + "Failed to init URBs copy operations.\n");
> + return -ENOMEM;
> + }
> +
> size = npackets * psize;
>
> if (usb_endpoint_dir_in(&ep->desc))
> @@ -2147,6 +2194,8 @@ int uvc_video_init(struct uvc_streaming *stream)
> }
> }
>
> + stream->urb_max_packets = UVC_MAX_PACKETS;
> +
> /* Prepare asynchronous work items. */
> for_each_uvc_urb(uvc_urb, stream)
> INIT_WORK(&uvc_urb->work, uvc_video_copy_data_work);
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index cce5e38..00cf6c9 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -561,7 +561,7 @@ struct uvc_urb {
> struct sg_table *sgt;
>
> unsigned int async_operations;
> - struct uvc_copy_op copy_operations[UVC_MAX_PACKETS];
> + struct uvc_copy_op *copy_operations;
> struct work_struct work;
> };
>
> @@ -616,6 +616,7 @@ struct uvc_streaming {
>
> struct uvc_urb uvc_urb[UVC_URBS];
> unsigned int urb_size;
> + unsigned int urb_max_packets;
>
> u32 sequence;
> u8 last_fid;
> --
> 2.10.2
>
--
Ricardo Ribalda
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