Hi Dongwon,
On 5 April 2016 at 01:14, 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
>
> v2
> - use thread functions defined in C11/threads.h instead of
> using direct pthread calls
> - make the timeout set with reference to CLOCK_MONOTONIC
> - cleaned up the way expiration time is calculated
> - (bug fix) in dri2_client_wait_sync, case EGL_SYNC_CL_EVENT_KHR
> has been added.
> - (bug fix) in dri2_destroy_sync, return from cond_broadcast
> call is now stored in 'err' intead of 'ret' to prevent 'ret'
> from being reset to 'EGL_FALSE' even in successful case
> - corrected minor syntax problems
>
> v3
> - dri2_egl_unref_sync now became 'void' type. No more error check
> is needed for this function call as a result.
> - (bug fix) resolved issue with duplicated unlocking of display in
> eglClientWaitSync when type of sync is "EGL_KHR_REUSABLE_SYNC"
>
> Signed-off-by: Dongwon Kim <dongwon....@intel.com>
> ---
> src/egl/drivers/dri2/egl_dri2.c | 192
> ++++++++++++++++++++++++++++++++++++++--
> src/egl/drivers/dri2/egl_dri2.h | 2 +
> src/egl/main/eglapi.c | 17 +++-
> src/egl/main/eglsync.c | 3 +-
> 4 files changed, 206 insertions(+), 8 deletions(-)
>
> diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
> index 8f50f0c..490b040 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 <c11/threads.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) {
> @@ -2394,7 +2398,12 @@ dri2_egl_unref_sync(struct dri2_egl_display *dri2_dpy,
> struct dri2_egl_sync *dri2_sync)
> {
> if (p_atomic_dec_zero(&dri2_sync->refcount)) {
> - dri2_dpy->fence->destroy_fence(dri2_dpy->dri_screen, dri2_sync->fence);
> + if (dri2_sync->base.Type == EGL_SYNC_REUSABLE_KHR)
> + cnd_destroy(&dri2_sync->cond);
> +
> + if (dri2_sync->fence)
> + dri2_dpy->fence->destroy_fence(dri2_dpy->dri_screen,
> dri2_sync->fence);
> +
> free(dri2_sync);
> }
> }
> @@ -2408,6 +2417,8 @@ 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;
> + pthread_condattr_t attr;
>
> dri2_sync = calloc(1, sizeof(struct dri2_egl_sync));
> if (!dri2_sync) {
> @@ -2450,6 +2461,37 @@ 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:
> + /* intialize attr */
typo -> initialize
> + ret = pthread_condattr_init(&attr);
> +
> + if (ret) {
> + _eglError(EGL_BAD_ACCESS, "eglCreateSyncKHR");
> + free(dri2_sync);
> + return NULL;
> + }
> +
> + /* change clock attribute to CLOCK_MONOTONIC */
> + ret = pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
> +
> + if (ret) {
> + _eglError(EGL_BAD_ACCESS, "eglCreateSyncKHR");
> + free(dri2_sync);
> + return NULL;
> + }
> +
> + ret = pthread_cond_init(&dri2_sync->cond, &attr);
> +
> + if (ret) {
> + _eglError(EGL_BAD_ACCESS, "eglCreateSyncKHR");
> + 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 +2503,27 @@ 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;
> +
> + /* 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 */
> + err = cnd_broadcast(&dri2_sync->cond);
>
> + if (err) {
> + _eglError(EGL_BAD_ACCESS, "eglDestroySyncKHR");
> + ret = EGL_FALSE;
> + }
> + }
> dri2_egl_unref_sync(dri2_dpy, dri2_sync);
> - return EGL_TRUE;
> +
> + return ret;
> }
>
> static EGLint
> @@ -2471,10 +2531,16 @@ 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 cnd_timedwait */
> + struct timespec current;
> + xtime expire;
> +
Please squash the above whitespace.
> EGLint ret = EGL_CONDITION_SATISFIED_KHR;
>
> /* The EGL_KHR_fence_sync spec states:
> @@ -2488,17 +2554,130 @@ 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:
> + case EGL_SYNC_CL_EVENT_KHR:
> + 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;
> + 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 (mtx_lock(&dri2_sync->mutex)) {
It's quite admirable that you've added the lock/unlock error checking.
Then again all of mesa (some 200+ cases of lock/unlock) don't bother,
so I'd just drop them for now.
> + /* if reusable sync has not been yet signaled */
> + if (dri2_sync->base.SyncStatus != EGL_SIGNALED_KHR) {
> + clock_gettime(CLOCK_MONOTONIC, ¤t);
> +
> + /* calculating when to expire */
> + expire.nsec = timeout % 1000000000L;
> + expire.sec = timeout / 1000000000L;
> +
> + expire.nsec += current.tv_nsec;
> + expire.sec += current.tv_sec;
> +
> + /* expire.nsec now is a number between 0 and 1999999998 */
> + if (expire.nsec > 999999999L) {
> + expire.sec++;
> + expire.nsec -= 1000000000L;
Albeit unlikely to change these soon, they feel error prone. Might
replacing them with 1000 * 1000 * 1000L derived equivalents ?
> + }
> +
> + if (mtx_lock(&dri2_sync->mutex)) {
> + ret = EGL_FALSE;
> + goto cleanup;
> + }
> +
> + ret = cnd_timedwait(&dri2_sync->cond, &dri2_sync->mutex,
> &expire);
> +
> + if (mtx_unlock(&dri2_sync->mutex)) {
> + ret = EGL_FALSE;
> + goto cleanup;
> + }
> +
> + if (ret)
> + if (ret == thrd_busy) {
> + if (dri2_sync->base.SyncStatus == EGL_UNSIGNALED_KHR) {
> + ret = EGL_TIMEOUT_EXPIRED_KHR;
> + } else {
> + _eglError(EGL_BAD_ACCESS, "eglClientWaitSyncKHR");
> + ret = EGL_FALSE;
Afaics this is wrong. The eglClientWaitSyncKHR does not return
EGL_TRUE/FALSE but
EGL_TIMEOUT_EXPIRED_KHR/EGL_CONDITION_SATISFIED_KHR.
> + }
> + }
> + }
> + }
> + break;
> + }
> +
> + cleanup:
> dri2_egl_unref_sync(dri2_dpy, dri2_sync);
> +
> + if (ret == EGL_FALSE) {
> + _eglError(EGL_BAD_ACCESS, "eglClientWaitSyncKHR");
> + return EGL_FALSE;
> + }
> +
With the above two suggestions (removed lock/unlock error handling and
feeding the correct value to ret, this hunk can be dropped.
Thanks for the contribution.
-Emil
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