On Fri, Mar 27, 2009 at 8:58 PM, Jesse Barnes <jbar...@virtuousgeek.org> wrote:
> This patch speeds up drmModeGetConnector by pre-allocating mode &
> property info space before calling into the kernel. In many cases this
> pre-allocation will be sufficient to hold the returned values (it's
> easy enough to tweak if the common case becomes larger), which means we
> don't have to make the second call, which saves a lot of time.
>
> Any comments or problems with the patch?
Looks good, I do wonder how much time do we save on doing pre
allocation, just curious? Anyways the patch is
Acked-by: Jakob Bornecrantz <wallbra...@gmail.com>
Cheers Jakob.
>
> Thanks,
> --
> Jesse Barnes, Intel Open Source Technology Center
>
> diff --git a/libdrm/xf86drmMode.c b/libdrm/xf86drmMode.c
> index 872604f..e2aba81 100644
> --- a/libdrm/xf86drmMode.c
> +++ b/libdrm/xf86drmMode.c
> @@ -357,21 +357,45 @@ drmModeConnectorPtr drmModeGetConnector(int fd,
> uint32_t connector_id)
> {
> struct drm_mode_get_connector conn;
> drmModeConnectorPtr r = NULL;
> + int pre_props = 8, pre_modes = 16, pre_encoders = 4;
>
> conn.connector_id = connector_id;
> conn.connector_type_id = 0;
> conn.connector_type = 0;
> - conn.count_modes = 0;
> - conn.modes_ptr = 0;
> - conn.count_props = 0;
> - conn.props_ptr = 0;
> - conn.prop_values_ptr = 0;
> - conn.count_encoders = 0;
> - conn.encoders_ptr = 0;
> + conn.count_modes = pre_modes;
> + conn.count_props = pre_props;
> + conn.count_encoders = pre_encoders;
> +
> + /*
> + * Pre-allocate space for some modes, properties, and encoders. If
> + * we're lucky we won't need to call into the kernel twice.
> + */
> + conn.props_ptr = VOID2U64(drmMalloc(pre_props * sizeof(uint32_t)));
> + conn.prop_values_ptr = VOID2U64(drmMalloc(pre_props *
> + sizeof(uint64_t)));
> + conn.modes_ptr = VOID2U64(drmMalloc(pre_modes *
> + sizeof(struct
> drm_mode_modeinfo)));
> + conn.encoders_ptr = VOID2U64(drmMalloc(pre_encoders *
> + sizeof(uint32_t)));
>
> if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn))
> return 0;
>
> + if (conn.count_props <= pre_props &&
> + conn.count_modes <= pre_modes &&
> + conn.count_encoders <= pre_encoders)
> + goto done;
> +
> + /* Oh well, free & reallocate everything and ask again... */
> + drmFree(U642VOID(conn.prop_values_ptr));
> + drmFree(U642VOID(conn.props_ptr));
> + drmFree(U642VOID(conn.modes_ptr));
> + drmFree(U642VOID(conn.encoders_ptr));
> + conn.prop_values_ptr = 0;
> + conn.props_ptr = 0;
> + conn.modes_ptr = 0;
> + conn.encoders_ptr = 0;
> +
> if (conn.count_props) {
> conn.props_ptr =
> VOID2U64(drmMalloc(conn.count_props*sizeof(uint32_t)));
> conn.prop_values_ptr =
> VOID2U64(drmMalloc(conn.count_props*sizeof(uint64_t)));
> @@ -386,6 +410,7 @@ drmModeConnectorPtr drmModeGetConnector(int fd, uint32_t
> connector_id)
> if (drmIoctl(fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn))
> goto err_allocs;
>
> +done:
> if(!(r = drmMalloc(sizeof(*r)))) {
> goto err_allocs;
> }
>
------------------------------------------------------------------------------
--
_______________________________________________
Dri-devel mailing list
Dri-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/dri-devel
