On Mon, Mar 21, 2016 at 08:35:20PM +0100, Marek Olšák wrote:
> On Wed, Mar 9, 2016 at 2:28 AM, Dongwon Kim <dongwon....@intel.com> wrote:
> > This patch enables an EGL extension, EGL_KHR_reusable_sync.
> > This new extension basically provides a way for multiple APIs or
> > threads to be excuted synchronously via a "reusable sync"
> > primitive shared by those threads/API calls.
> >
> > This was implemented based on the specification at
> >
> > https://www.khronos.org/registry/egl/extensions/KHR/EGL_KHR_reusable_sync.txt
> >
> > Signed-off-by: Dongwon Kim <dongwon....@intel.com>
> > ---
> > src/egl/drivers/dri2/egl_dri2.c | 197
> > ++++++++++++++++++++++++++++++++++++++--
> > src/egl/drivers/dri2/egl_dri2.h | 2 +
> > src/egl/main/eglapi.c | 8 ++
> > src/egl/main/eglsync.c | 3 +-
> > 4 files changed, 200 insertions(+), 10 deletions(-)
> >
> > diff --git a/src/egl/drivers/dri2/egl_dri2.c
> > b/src/egl/drivers/dri2/egl_dri2.c
> > index 8f50f0c..78164e4 100644
> > --- a/src/egl/drivers/dri2/egl_dri2.c
> > +++ b/src/egl/drivers/dri2/egl_dri2.c
> > @@ -38,6 +38,8 @@
> > #include <fcntl.h>
> > #include <errno.h>
> > #include <unistd.h>
> > +#include <pthread.h>
> > +#include <time.h>
> > #ifdef HAVE_LIBDRM
> > #include <xf86drm.h>
> > #include <drm_fourcc.h>
> > @@ -623,6 +625,8 @@ dri2_setup_screen(_EGLDisplay *disp)
> > disp->Extensions.KHR_cl_event2 = EGL_TRUE;
> > }
> >
> > + disp->Extensions.KHR_reusable_sync = EGL_TRUE;
> > +
> > if (dri2_dpy->image) {
> > if (dri2_dpy->image->base.version >= 10 &&
> > dri2_dpy->image->getCapabilities != NULL) {
> > @@ -2389,14 +2393,33 @@ dri2_egl_ref_sync(struct dri2_egl_sync *sync)
> > p_atomic_inc(&sync->refcount);
> > }
> >
> > -static void
> > +static EGLint
> > dri2_egl_unref_sync(struct dri2_egl_display *dri2_dpy,
> > struct dri2_egl_sync *dri2_sync)
> > {
> > + EGLint ret;
> > +
> > if (p_atomic_dec_zero(&dri2_sync->refcount)) {
> > - dri2_dpy->fence->destroy_fence(dri2_dpy->dri_screen,
> > dri2_sync->fence);
> > + /* mutex and cond should be freed if not freed yet. */
> > + if (dri2_sync->mutex)
> > + free(dri2_sync->mutex);
> > +
> > + if (dri2_sync->cond) {
> > + ret = pthread_cond_destroy(dri2_sync->cond);
> > +
> > + if (ret)
> > + return EGL_FALSE;
> > +
> > + free(dri2_sync->cond);
> > + }
> > +
> > + if (dri2_sync->fence)
> > + dri2_dpy->fence->destroy_fence(dri2_dpy->dri_screen,
> > dri2_sync->fence);
> > +
> > free(dri2_sync);
> > }
> > +
> > + return EGL_TRUE;
> > }
> >
> > static _EGLSync *
> > @@ -2408,6 +2431,7 @@ dri2_create_sync(_EGLDriver *drv, _EGLDisplay *dpy,
> > struct dri2_egl_display *dri2_dpy = dri2_egl_display(dpy);
> > struct dri2_egl_context *dri2_ctx = dri2_egl_context(ctx);
> > struct dri2_egl_sync *dri2_sync;
> > + EGLint ret;
> >
> > dri2_sync = calloc(1, sizeof(struct dri2_egl_sync));
> > if (!dri2_sync) {
> > @@ -2450,6 +2474,23 @@ dri2_create_sync(_EGLDriver *drv, _EGLDisplay *dpy,
> > dri2_sync->fence, 0, 0))
> > dri2_sync->base.SyncStatus = EGL_SIGNALED_KHR;
> > break;
> > +
> > + case EGL_SYNC_REUSABLE_KHR:
> > + dri2_sync->cond = calloc(1, sizeof(pthread_cond_t));
> > + dri2_sync->mutex = calloc(1, sizeof(pthread_mutex_t));
> > + ret = pthread_cond_init(dri2_sync->cond, NULL);
> > +
> > + if (ret) {
> > + _eglError(EGL_BAD_PARAMETER, "eglCreateSyncKHR");
> > + free(dri2_sync->cond);
> > + free(dri2_sync->mutex);
> > + free(dri2_sync);
> > + return NULL;
> > + }
> > +
> > + /* initial status of reusable sync must be "unsignaled" */
> > + dri2_sync->base.SyncStatus = EGL_UNSIGNALED_KHR;
> > + break;
> > }
> >
> > p_atomic_set(&dri2_sync->refcount, 1);
> > @@ -2461,9 +2502,33 @@ dri2_destroy_sync(_EGLDriver *drv, _EGLDisplay *dpy,
> > _EGLSync *sync)
> > {
> > struct dri2_egl_display *dri2_dpy = dri2_egl_display(dpy);
> > struct dri2_egl_sync *dri2_sync = dri2_egl_sync(sync);
> > + EGLint ret = EGL_TRUE;
> > + EGLint err;
> >
> > - dri2_egl_unref_sync(dri2_dpy, dri2_sync);
> > - return EGL_TRUE;
> > + /* if type of sync is EGL_SYNC_REUSABLE_KHR and it is not signaled yet,
> > + * then unlock all threads possibly blocked by the reusable sync before
> > + * destroying it.
> > + */
> > + if (dri2_sync->base.Type == EGL_SYNC_REUSABLE_KHR &&
> > + dri2_sync->base.SyncStatus == EGL_UNSIGNALED_KHR) {
> > + dri2_sync->base.SyncStatus = EGL_SIGNALED_KHR;
> > + /* unblock all threads currently blocked by sync */
> > + ret = pthread_cond_broadcast(dri2_sync->cond);
> > +
> > + if (ret) {
> > + _eglError(EGL_BAD_PARAMETER, "eglDestroySyncKHR");
> > + ret = EGL_FALSE;
>
> BAD_PARAMETER is not the correct error for a pthread_cond_broadcast
> failure. I'm not sure, but I think we shouldn't return an error in
> this case, since the specification doesn't define an error for it.
> According to pthread documentation, this error shouldn't occur if
> dri2_sync->cond is valid, thus it shouldn't be an issue right?
>
> Same for error handling of other pthread functions.
Don't we need to make it fail anyway if pthread function
gets an error? What about just get it return EGL_FALSE
without any error code? Is it allowed here?
>
> > + }
> > + }
> > +
> > + err = dri2_egl_unref_sync(dri2_dpy, dri2_sync);
> > +
> > + if (err == EGL_FALSE) {
> > + _eglError(EGL_BAD_PARAMETER, "eglDestroySyncKHR");
> > + ret = EGL_FALSE;
> > + }
> > +
> > + return ret;
> > }
> >
> > static EGLint
> > @@ -2471,11 +2536,18 @@ dri2_client_wait_sync(_EGLDriver *drv, _EGLDisplay
> > *dpy, _EGLSync *sync,
> > EGLint flags, EGLTime timeout)
> > {
> > _EGLContext *ctx = _eglGetCurrentContext();
> > + struct dri2_egl_driver *dri2_drv = dri2_egl_driver(drv);
> > struct dri2_egl_display *dri2_dpy = dri2_egl_display(dpy);
> > struct dri2_egl_context *dri2_ctx = dri2_egl_context(ctx);
> > struct dri2_egl_sync *dri2_sync = dri2_egl_sync(sync);
> > unsigned wait_flags = 0;
> > +
> > + /* timespecs for pthread_cond_timedwait */
> > + struct timespec current;
> > + struct timespec expired;
> > +
> > EGLint ret = EGL_CONDITION_SATISFIED_KHR;
> > + EGLint err;
> >
> > /* The EGL_KHR_fence_sync spec states:
> > *
> > @@ -2488,17 +2560,123 @@ dri2_client_wait_sync(_EGLDriver *drv, _EGLDisplay
> > *dpy, _EGLSync *sync,
> > /* the sync object should take a reference while waiting */
> > dri2_egl_ref_sync(dri2_sync);
> >
> > - if (dri2_dpy->fence->client_wait_sync(dri2_ctx ? dri2_ctx->dri_context
> > : NULL,
> > + switch (sync->Type) {
> > + case EGL_SYNC_FENCE_KHR:
>
> This should also be executed for EGL_SYNC_CL_EVENT_KHR.
>
Will fix this in version 2
> > + if (dri2_dpy->fence->client_wait_sync(dri2_ctx ?
> > dri2_ctx->dri_context : NULL,
> > dri2_sync->fence, wait_flags,
> > timeout))
> > - dri2_sync->base.SyncStatus = EGL_SIGNALED_KHR;
> > - else
> > - ret = EGL_TIMEOUT_EXPIRED_KHR;
> > + dri2_sync->base.SyncStatus = EGL_SIGNALED_KHR;
> > + else
> > + ret = EGL_TIMEOUT_EXPIRED_KHR;
>
> No need to add an empty line here:
>
Will be fixed in version 2
> > +
> > + break;
> > +
> > + case EGL_SYNC_REUSABLE_KHR:
> > + if (dri2_ctx && dri2_sync->base.SyncStatus==EGL_UNSIGNALED_KHR &&
> > + (flags & EGL_SYNC_FLUSH_COMMANDS_BIT_KHR)) {
> > + /* flush context if EGL_SYNC_FLUSH_COMMANDS_BIT_KHR is set */
> > + if (dri2_drv->glFlush)
> > + dri2_drv->glFlush();
> > + }
> > +
> > + /* if timeout is EGL_FOREVER_KHR, it should wait without any
> > timeout.*/
> > + if (timeout == EGL_FOREVER_KHR) {
> > + if (pthread_mutex_lock(dri2_sync->mutex)) {
> > + ret = EGL_FALSE;
> > + goto cleanup;
> > + }
> > +
> > + ret = pthread_cond_wait(dri2_sync->cond, dri2_sync->mutex);
> > +
> > + if (pthread_mutex_unlock(dri2_sync->mutex)) {
> > + ret = EGL_FALSE;
> > + goto cleanup;
> > + }
> > +
> > + if (ret) {
> > + _eglError(EGL_BAD_PARAMETER, "eglClientWaitSyncKHR");
> > + ret = EGL_FALSE;
> > + }
> > + } else {
> > + /* if reusable sync has not been yet signaled */
> > + if (dri2_sync->base.SyncStatus!=EGL_SIGNALED_KHR) {
>
> Missing spaces around !=.
>
Will be fixed in version 2
> > +
> > + clock_gettime(CLOCK_REALTIME, ¤t);
>
> We should use CLOCK_MONOTONIC everywhere.
>
Will be fixed in version 2
> > +
> > + expired.tv_nsec = current.tv_nsec + timeout;
>
> This needs to handle integer overflows, otherwise you can get negative
> tv_nsec. Also, tv_nsec only has 32 bits on 32-bit CPUs, which should
> also be dealt with.
>
Will be fixed in version 2
> > + expired.tv_sec = current.tv_sec + expired.tv_nsec/1000000000L;
> > + expired.tv_nsec = current.tv_nsec%1000000000L;
> > +
> > + if (pthread_mutex_lock(dri2_sync->mutex)) {
> > + ret = EGL_FALSE;
> > + goto cleanup;
> > + }
> > +
> > + ret = pthread_cond_timedwait(dri2_sync->cond,
> > dri2_sync->mutex, &expired);
> > +
> > + if (pthread_mutex_unlock(dri2_sync->mutex)) {
> > + ret = EGL_FALSE;
> > + goto cleanup;
> > + }
> > +
> > + if (ret)
> > + if (ret == ETIMEDOUT) {
> > + if (dri2_sync->base.SyncStatus==EGL_UNSIGNALED_KHR) {
> > + ret = EGL_TIMEOUT_EXPIRED_KHR;
> > + } else {
> > + _eglError(EGL_BAD_PARAMETER, "eglClientWaitSyncKHR");
> > + ret = EGL_FALSE;
> > + }
> > + }
> > + }
> > + }
> > + break;
> > + }
> > +
> > + cleanup:
> > + err = dri2_egl_unref_sync(dri2_dpy, dri2_sync);
> > +
> > + /* fail to unreference dri2_sync */
> > + if (ret == EGL_FALSE || err == EGL_FALSE) {
> > + _eglError(EGL_BAD_PARAMETER, "eglClientWaitSyncKHR");
> > + return EGL_FALSE;
> > + }
> >
> > - dri2_egl_unref_sync(dri2_dpy, dri2_sync);
> > return ret;
> > }
> >
> > +static EGLBoolean
> > +dri2_signal_sync(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSync *sync,
> > + EGLenum mode)
> > +{
> > + struct dri2_egl_sync *dri2_sync = dri2_egl_sync(sync);
> > + EGLint ret;
> > +
> > + if (sync->Type!=EGL_SYNC_REUSABLE_KHR) {
>
> Missing spaces around !=.
>
Will be fixed in version 2
> > + _eglError(EGL_BAD_MATCH, "eglSignalSyncKHR");
> > + return EGL_FALSE;
> > + }
> > +
> > + if (mode != EGL_SIGNALED_KHR && mode != EGL_UNSIGNALED_KHR) {
> > + _eglError(EGL_BAD_ATTRIBUTE, "eglSignalSyncKHR");
> > + return EGL_FALSE;
> > + }
> > +
> > + dri2_sync->base.SyncStatus = mode;
> > +
> > + if (mode == EGL_SIGNALED_KHR) {
> > + ret = pthread_cond_broadcast(dri2_sync->cond);
> > +
> > + /* fail to broadcast */
> > + if (ret) {
> > + _eglError(EGL_BAD_PARAMETER, "eglSignalSyncKHR");
> > + return EGL_FALSE;
> > + }
> > + }
> > +
> > + return EGL_TRUE;
> > +}
> > +
> > static EGLint
> > dri2_server_wait_sync(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSync *sync)
> > {
> > @@ -2620,6 +2798,7 @@ _eglBuiltInDriverDRI2(const char *args)
> > dri2_drv->base.API.GetSyncValuesCHROMIUM =
> > dri2_get_sync_values_chromium;
> > dri2_drv->base.API.CreateSyncKHR = dri2_create_sync;
> > dri2_drv->base.API.ClientWaitSyncKHR = dri2_client_wait_sync;
> > + dri2_drv->base.API.SignalSyncKHR = dri2_signal_sync;
> > dri2_drv->base.API.WaitSyncKHR = dri2_server_wait_sync;
> > dri2_drv->base.API.DestroySyncKHR = dri2_destroy_sync;
> >
> > diff --git a/src/egl/drivers/dri2/egl_dri2.h
> > b/src/egl/drivers/dri2/egl_dri2.h
> > index 52ad92b..f70f384 100644
> > --- a/src/egl/drivers/dri2/egl_dri2.h
> > +++ b/src/egl/drivers/dri2/egl_dri2.h
> > @@ -307,6 +307,8 @@ struct dri2_egl_image
> >
> > struct dri2_egl_sync {
> > _EGLSync base;
> > + pthread_mutex_t *mutex;
> > + pthread_cond_t *cond;
>
> The types should be mtx_t and cnd_t from c11/threads.h. The
> corresponding functions from c11/threads.h should be used too.
Does this mean I need to replace all pthread functions that
I used here with things defined in threads.h intead? I can do
it but can I know why we can't use pthread.h?
>
> Also, declaring the variables as pointers seems unnecessary. Instead
> of checking the pointers against NULL, you can declare them as normal
> non-pointer variables and check (base.Type == EGL_SYNC_REUSABLE_KHR)
> instead.
I thought we can save space by definiting those as pointers.
(basically we don't have to allocate space for mutex and cond
if sync type is not reusable)
Thanks!
>
> It should also be clear from the variable names or comments that both
> variables are for EGL_SYNC_REUSABLE_KHR only.
>
> Thanks,
> Marek
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