[Mesa-dev] [PATCH 13/17] mesa: implement buffer/texture barriers for semaphore wait/signal
Nicolai Hähnle
nhaehnle at gmail.com
Fri Nov 3 09:18:05 UTC 2017
On 02.11.2017 04:57, Andres Rodriguez wrote:
> Make sure memory is accessible to the external client, for the specified
> memory object, before the signal/after the wait.
>
> Signed-off-by: Andres Rodriguez <andresx7 at gmail.com>
> ---
> src/mesa/main/dd.h | 14 ++++++-
> src/mesa/main/externalobjects.c | 38 ++++++++++++++---
> src/mesa/state_tracker/st_cb_semaphoreobjects.c | 55 ++++++++++++++++++++++++-
> 3 files changed, 98 insertions(+), 9 deletions(-)
>
> diff --git a/src/mesa/main/dd.h b/src/mesa/main/dd.h
> index ec9ed8e..5089c86 100644
> --- a/src/mesa/main/dd.h
> +++ b/src/mesa/main/dd.h
> @@ -1149,14 +1149,24 @@ struct dd_function_table {
> * server's command stream
> */
> void (*ServerWaitSemaphoreObject)(struct gl_context *ctx,
> - struct gl_semaphore_object *semObj);
> + struct gl_semaphore_object *semObj,
> + GLuint numBufferBarriers,
> + struct gl_buffer_object **bufObjs,
> + GLuint numTextureBarriers,
> + struct gl_texture_object **texObjs,
> + const GLenum *srcLayouts);
>
> /**
> * Introduce an operation to signal the semaphore object in the GL
> * server's command stream
> */
> void (*ServerSignalSemaphoreObject)(struct gl_context *ctx,
> - struct gl_semaphore_object *semObj);
> + struct gl_semaphore_object *semObj,
> + GLuint numBufferBarriers,
> + struct gl_buffer_object **bufObjs,
> + GLuint numTextureBarriers,
> + struct gl_texture_object **texObjs,
> + const GLenum *dstLayouts);
> /*@}*/
>
> /**
> diff --git a/src/mesa/main/externalobjects.c b/src/mesa/main/externalobjects.c
> index 67912dd..a7e42a9 100644
> --- a/src/mesa/main/externalobjects.c
> +++ b/src/mesa/main/externalobjects.c
> @@ -23,6 +23,7 @@
>
> #include "macros.h"
> #include "mtypes.h"
> +#include "bufferobj.h"
> #include "context.h"
> #include "externalobjects.h"
> #include "teximage.h"
> @@ -744,7 +745,8 @@ _mesa_WaitSemaphoreEXT(GLuint semaphore,
> {
> GET_CURRENT_CONTEXT(ctx);
> struct gl_semaphore_object *semObj;
> -
> + struct gl_buffer_object **bufObjs;
> + struct gl_texture_object **texObjs;
>
> if (!ctx->Extensions.EXT_semaphore) {
> _mesa_error(ctx, GL_INVALID_OPERATION, "glWaitSemaphoreEXT(unsupported)");
> @@ -757,8 +759,20 @@ _mesa_WaitSemaphoreEXT(GLuint semaphore,
> if (!semObj)
> return;
>
> - /* TODO: memory barriers and layout transitions */
> - ctx->Driver.ServerWaitSemaphoreObject(ctx, semObj);
> + bufObjs = alloca(sizeof(struct gl_buffer_object **) * numBufferBarriers);
> + for (unsigned i = 0; i < numBufferBarriers; i++) {
> + bufObjs[i] = _mesa_lookup_bufferobj(ctx, buffers[i]);
> + }
> +
> + texObjs = alloca(sizeof(struct gl_texture_object **) * numTextureBarriers);
> + for (unsigned i = 0; i < numTextureBarriers; i++) {
> + texObjs[i] = _mesa_lookup_texture(ctx, textures[i]);
> + }
> +
> + ctx->Driver.ServerWaitSemaphoreObject(ctx, semObj,
> + numBufferBarriers, bufObjs,
> + numTextureBarriers, texObjs,
> + srcLayouts);
> }
>
> void GLAPIENTRY
> @@ -771,6 +785,8 @@ _mesa_SignalSemaphoreEXT(GLuint semaphore,
> {
> GET_CURRENT_CONTEXT(ctx);
> struct gl_semaphore_object *semObj;
> + struct gl_buffer_object **bufObjs;
> + struct gl_texture_object **texObjs;
>
> if (!ctx->Extensions.EXT_semaphore) {
> _mesa_error(ctx, GL_INVALID_OPERATION, "glSignalSemaphoreEXT(unsupported)");
> @@ -783,8 +799,20 @@ _mesa_SignalSemaphoreEXT(GLuint semaphore,
> if (!semObj)
> return;
>
> - /* TODO: memory barriers and layout transitions */
> - ctx->Driver.ServerSignalSemaphoreObject(ctx, semObj);
> + bufObjs = alloca(sizeof(struct gl_buffer_object **) * numBufferBarriers);
> + for (unsigned i = 0; i < numBufferBarriers; i++) {
> + bufObjs[i] = _mesa_lookup_bufferobj(ctx, buffers[i]);
> + }
> +
> + texObjs = alloca(sizeof(struct gl_texture_object **) * numTextureBarriers);
> + for (unsigned i = 0; i < numTextureBarriers; i++) {
> + texObjs[i] = _mesa_lookup_texture(ctx, textures[i]);
> + }
> +
> + ctx->Driver.ServerSignalSemaphoreObject(ctx, semObj,
> + numBufferBarriers, bufObjs,
> + numTextureBarriers, texObjs,
> + dstLayouts);
> }
>
> void GLAPIENTRY
> diff --git a/src/mesa/state_tracker/st_cb_semaphoreobjects.c b/src/mesa/state_tracker/st_cb_semaphoreobjects.c
> index 4cff3fd..f6242c7 100644
> --- a/src/mesa/state_tracker/st_cb_semaphoreobjects.c
> +++ b/src/mesa/state_tracker/st_cb_semaphoreobjects.c
> @@ -6,6 +6,8 @@
> #include "main/externalobjects.h"
>
> #include "st_context.h"
> +#include "st_texture.h"
> +#include "st_cb_bufferobjects.h"
> #include "st_cb_semaphoreobjects.h"
>
> #include "state_tracker/drm_driver.h"
> @@ -51,25 +53,74 @@ st_import_semaphoreobj_fd(struct gl_context *ctx,
>
> static void
> st_server_wait_semaphore(struct gl_context *ctx,
> - struct gl_semaphore_object *semObj)
> + struct gl_semaphore_object *semObj,
> + GLuint numBufferBarriers,
> + struct gl_buffer_object **bufObjs,
> + GLuint numTextureBarriers,
> + struct gl_texture_object **texObjs,
> + const GLenum *srcLayouts)
> {
> struct st_semaphore_object *st_obj = st_semaphore_object(semObj);
> struct st_context *st = st_context(ctx);
> struct pipe_context *pipe = st->pipe;
> + struct st_buffer_object *bufObj;
> + struct st_texture_object *texObj;
>
> + for (unsigned i = 0; i < numBufferBarriers; i++) {
> + if (!bufObjs[i])
> + continue;
> +
> + bufObj = st_buffer_object(bufObjs[i]);
> + pipe->flush_resource(pipe, bufObj->buffer);
> + }
> +
> + for (unsigned i = 0; i < numTextureBarriers; i++) {
> + if (!texObjs[i])
> + continue;
> +
> + texObj = st_texture_object(texObjs[i]);
> + pipe->flush_resource(pipe, texObj->pt);
> + }
What's the justifications of these flushes? pipe_context::flush_resource
is described as
* Flush the resource cache, so that the resource can be used
* by an external client. Possible usage:
... but WaitSemaphore is about *importing* resources from an external
client (acquire semantics).
> +
> + /* TODO: layout transition */
> _mesa_flush(ctx);
> pipe->semobj_wait(pipe, st_obj->semaphore);
> }
>
> static void
> st_server_signal_semaphore(struct gl_context *ctx,
> - struct gl_semaphore_object *semObj)
> + struct gl_semaphore_object *semObj,
> + GLuint numBufferBarriers,
> + struct gl_buffer_object **bufObjs,
> + GLuint numTextureBarriers,
> + struct gl_texture_object **texObjs,
> + const GLenum *dstLayouts)
> {
> struct st_semaphore_object *st_obj = st_semaphore_object(semObj);
> struct st_context *st = st_context(ctx);
> struct pipe_context *pipe = st->pipe;
> + struct st_buffer_object *bufObj;
> + struct st_texture_object *texObj;
>
> pipe->semobj_signal(pipe, st_obj->semaphore);
> +
> + for (unsigned i = 0; i < numBufferBarriers; i++) {
> + if (!bufObjs[i])
> + continue;
> +
> + bufObj = st_buffer_object(bufObjs[i]);
> + pipe->flush_resource(pipe, bufObj->buffer);
> + }
> +
> + for (unsigned i = 0; i < numTextureBarriers; i++) {
> + if (!texObjs[i])
> + continue;
> +
> + texObj = st_texture_object(texObjs[i]);
> + pipe->flush_resource(pipe, texObj->pt);
> + }
These flushes must go before the call to semobj_signal: Logically, we
can only signal the semaphore *after* the resources have been flushed.
In practice, the code can indeed go wrong as-is, because each of the
flush_resource call can trigger an actually flush, so the semaphore can
really be signalled by a command submission that does not contain
flush_resource for the later resources.
Cheers,
Nicolai
> +
> + /* TODO: layout transition */
> _mesa_flush(ctx);
> }
>
>
--
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Aber vergiss niemals, wie sie sein sollte.
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