Mesa (master): gallium/os: add os_wait_until_zero (v2)
Marek Olšák
mareko at kemper.freedesktop.org
Sun Jul 5 13:09:52 UTC 2015
Module: Mesa
Branch: master
Commit: 3836857a777a248dd212ce7a1d7307d2984fda7d
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=3836857a777a248dd212ce7a1d7307d2984fda7d
Author: Marek Olšák <marek.olsak at amd.com>
Date: Thu Jun 25 20:39:34 2015 +0200
gallium/os: add os_wait_until_zero (v2)
This will be used by radeon and amdgpu winsyses.
Copied from the amdgpu winsys.
v2: use volatile and p_atomic_read
Reviewed-by: Brian Paul <brianp at vmware.com>
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
---
src/gallium/auxiliary/os/os_time.c | 38 +++++++++++++++++++++++++++++++++++-
src/gallium/auxiliary/os/os_time.h | 11 +++++++++++
2 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/src/gallium/auxiliary/os/os_time.c b/src/gallium/auxiliary/os/os_time.c
index f7e4ca4..bd09452 100644
--- a/src/gallium/auxiliary/os/os_time.c
+++ b/src/gallium/auxiliary/os/os_time.c
@@ -33,11 +33,13 @@
*/
-#include "pipe/p_config.h"
+#include "pipe/p_defines.h"
+#include "util/u_atomic.h"
#if defined(PIPE_OS_UNIX)
# include <time.h> /* timeval */
# include <sys/time.h> /* timeval */
+# include <sched.h> /* sched_yield */
#elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
# include <windows.h>
#else
@@ -92,3 +94,37 @@ os_time_sleep(int64_t usecs)
}
#endif
+
+
+bool
+os_wait_until_zero(volatile int *var, uint64_t timeout)
+{
+ if (!p_atomic_read(var))
+ return true;
+
+ if (!timeout)
+ return false;
+
+ if (timeout == PIPE_TIMEOUT_INFINITE) {
+ while (p_atomic_read(var)) {
+#if defined(PIPE_OS_UNIX)
+ sched_yield();
+#endif
+ }
+ return true;
+ }
+ else {
+ int64_t start_time = os_time_get_nano();
+ int64_t end_time = start_time + timeout;
+
+ while (p_atomic_read(var)) {
+ if (os_time_timeout(start_time, end_time, os_time_get_nano()))
+ return false;
+
+#if defined(PIPE_OS_UNIX)
+ sched_yield();
+#endif
+ }
+ return true;
+ }
+}
diff --git a/src/gallium/auxiliary/os/os_time.h b/src/gallium/auxiliary/os/os_time.h
index 4fab03c..2989af1 100644
--- a/src/gallium/auxiliary/os/os_time.h
+++ b/src/gallium/auxiliary/os/os_time.h
@@ -94,6 +94,17 @@ os_time_timeout(int64_t start,
}
+/**
+ * Wait until the variable at the given memory location is zero.
+ *
+ * \param var variable
+ * \param timeout timeout in ns, can be anything from 0 (no wait) to
+ * PIPE_TIME_INFINITE (wait forever)
+ * \return true if the variable is zero
+ */
+bool
+os_wait_until_zero(volatile int *var, uint64_t timeout);
+
#ifdef __cplusplus
}
#endif
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