On 20/11/2020 17:26, Lynne wrote:
This improves performance and helps a little when given FDs without
any synchronization fences.
Patch attached.
> From b4b0b8038bef08cf3dae9daa78eca3a675b67f89 Mon Sep 17 00:00:00 2001
> From: Lynne <d...@lynne.ee>
> Date: Fri, 20 Nov 2020 18:23:42 +0100
> Subject: [PATCH] hwcontext_drm: issue DMA_BUF_IOCTL_SYNC when mapping FDs
>
> This improves performance and helps a little when given FDs without
> any synchronization fences.
> ---
> libavutil/hwcontext_drm.c | 36 +++++++++++++++++++++++++++++++-----
> 1 file changed, 31 insertions(+), 5 deletions(-)
>
> diff --git a/libavutil/hwcontext_drm.c b/libavutil/hwcontext_drm.c
> index 32cbde82eb..ceacf683a0 100644
> --- a/libavutil/hwcontext_drm.c
> +++ b/libavutil/hwcontext_drm.c
> @@ -19,6 +19,8 @@
> #include <fcntl.h>
> #include <sys/mman.h>
> #include <unistd.h>
> +#include <linux/dma-buf.h>
Is it possible that adding raw ioctl() calls will cause problems on non-Linux
platforms with libdrm, like FreeBSD? (Maybe they implement the same ioctl()s,
I don't know.)
> +#include <sys/ioctl.h>
>
> #include <drm.h>
> #include <xf86drm.h>
> @@ -85,6 +87,8 @@ static int drm_get_buffer(AVHWFramesContext *hwfc, AVFrame
*frame)
> typedef struct DRMMapping {
> // Address and length of each mmap()ed region.
> int nb_regions;
> + int sync_flags;
> + int object[AV_DRM_MAX_PLANES];
> void *address[AV_DRM_MAX_PLANES];
> size_t length[AV_DRM_MAX_PLANES];
> } DRMMapping;
> @@ -93,10 +97,16 @@ static void drm_unmap_frame(AVHWFramesContext *hwfc,
> HWMapDescriptor *hwmap)
> {
> DRMMapping *map = hwmap->priv;
> - int i;
> -
> - for (i = 0; i < map->nb_regions; i++)
> + struct dma_buf_sync sync = { .flags = DMA_BUF_SYNC_END | map->sync_flags
};
> + int i, ret;
> +
> + for (i = 0; i < map->nb_regions; i++) {
> + ret = ioctl(map->object[i], DMA_BUF_IOCTL_SYNC, &sync);
> + if (ret)
> + av_log(hwfc, AV_LOG_ERROR, "Failed to issue ioctl sync to DRM object
"
> + "%d: %d.\n", map->object[i], errno);
> munmap(map->address[i], map->length[i]);
> + }
>
> av_free(map);
> }
> @@ -105,6 +115,7 @@ static int drm_map_frame(AVHWFramesContext *hwfc,
> AVFrame *dst, const AVFrame *src, int flags)
> {
> const AVDRMFrameDescriptor *desc = (AVDRMFrameDescriptor*)src->data[0];
> + struct dma_buf_sync sync_start = { 0 };
> DRMMapping *map;
> int err, i, p, plane;
> int mmap_prot;
> @@ -115,10 +126,16 @@ static int drm_map_frame(AVHWFramesContext *hwfc,
> return AVERROR(ENOMEM);
>
> mmap_prot = 0;
> - if (flags & AV_HWFRAME_MAP_READ)
> + if (flags & AV_HWFRAME_MAP_READ) {
> mmap_prot |= PROT_READ;
> - if (flags & AV_HWFRAME_MAP_WRITE)
> + map->sync_flags |= DMA_BUF_SYNC_READ;
> + }
> + if (flags & AV_HWFRAME_MAP_WRITE) {
> mmap_prot |= PROT_WRITE;
> + map->sync_flags |= DMA_BUF_SYNC_WRITE;
> + }
> +
> + sync_start.flags = DMA_BUF_SYNC_START | map->sync_flags;
>
> av_assert0(desc->nb_objects <= AV_DRM_MAX_PLANES);
> for (i = 0; i < desc->nb_objects; i++) {
> @@ -133,6 +150,15 @@ static int drm_map_frame(AVHWFramesContext *hwfc,
>
> map->address[i] = addr;
> map->length[i] = desc->objects[i].size;
> + map->object[i] = desc->objects[i].fd;
> +
> + err = ioctl(desc->objects[i].fd, DMA_BUF_IOCTL_SYNC, &sync_start);
> + if (err) {
> + err = AVERROR(errno);
> + av_log(hwfc, AV_LOG_ERROR, "Failed to issue ioctl sync to DRM object
"
> + "%d: %d.\n", desc->objects[i].fd, errno);
> + goto fail;
> + }
> }
> map->nb_regions = i;
>
> --
> 2.29.2
>
Patch LGTM if we can check the compatibility.
Thanks,
- Mark
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