I still don't really like this but I agree that this code really should not be getting hit very often so it's probably not too bad. Maybe one day we'll be able to drop the non-syncobj paths entirely. Wouldn't that be nice. In the mean time, this is probably fine. I did see one issue below with time conversions that should be fixed though.
On Thu, Jun 14, 2018 at 7:52 PM, Keith Packard <keithp@xxxxxxxxxx> wrote:
Handle the case where the set of fences to wait for is not all of the
same type by either waiting for them sequentially (waitAll), or
polling them until the timer has expired (!waitAll). We hope the
latter case is not common.
While the current code makes sure that it always has fences of only
one type, that will not be true when we add WSI fences. Split out this
refactoring to make merging that clearer.
v2: Adopt Jason Ekstrand's coding conventions
Declare variables at first use, eliminate extra whitespace between
types and names. Wrap lines to 80 columns.
Suggested-by: Jason Ekstrand <jason.ekstrand@xxxxxxxxx>
Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
---
src/intel/vulkan/anv_queue.c | 105 +++++++++++++++++++++++++++++------
1 file changed, 88 insertions(+), 17 deletions(-)
diff --git a/src/intel/vulkan/anv_queue.c b/src/intel/vulkan/anv_queue.c
index 6fe04a0a19d..8df99c84549 100644
--- a/src/intel/vulkan/anv_queue.c
+++ b/src/intel/vulkan/anv_queue.c
@@ -459,12 +459,32 @@ gettime_ns(void)
return (uint64_t)current.tv_sec * NSEC_PER_SEC + current.tv_nsec;
}
+static uint64_t anv_get_absolute_timeout(uint64_t timeout)
+{
+ if (timeout == 0)
+ return 0;
+ uint64_t current_time = gettime_ns();
+
+ timeout = MIN2(INT64_MAX - current_time, timeout);
+
+ return (current_time + timeout);
+}
This does not have the same behavior as the code it replaces. In particular, the old code saturates at INT64_MAX whereas this code does not do so properly anymore. If UINT64_MAX gets passed into timeout, I believe that will be implicitly casted to signed and the MIN will yield -1 which gets casted back to unsigned and you get UINT64_MAX again. This is a problem because the value we pass into the kernel ioctls is signed. The behavior of the kernel *should* be infinite when timeout < 0 but, on some older kernels, -1 is treated as 0 and you get no timeout.
That said, I think I just saw a bug in the old code which I'll point out below.
+
+static int64_t anv_get_relative_timeout(uint64_t abs_timeout)
+{
+ uint64_t now = gettime_ns();
+
+ if (abs_timeout < now)
+ return 0;
+ return abs_timeout - now;
+}
+
static VkResult
anv_wait_for_syncobj_fences(struct anv_device *device,
uint32_t fenceCount,
const VkFence *pFences,
bool waitAll,
- uint64_t _timeout)
+ uint64_t abs_timeout_ns)
{
uint32_t *syncobjs = vk_zalloc(&device->alloc,
sizeof(*syncobjs) * fenceCount, 8,
@@ -484,19 +504,6 @@ anv_wait_for_syncobj_fences(struct anv_device *device,
syncobjs[i] = impl->syncobj;
}
- int64_t abs_timeout_ns = 0;
- if (_timeout > 0) {
- uint64_t current_ns = gettime_ns();
-
- /* Add but saturate to INT32_MAX */
- if (current_ns + _timeout < current_ns)
- abs_timeout_ns = INT64_MAX;
- else if (current_ns + _timeout > INT64_MAX)
I suspect we need to cast INT64_MAX to a uint64_t here to ensure we don't accidentally get an implicit conversion to signed.
- abs_timeout_ns = INT64_MAX;
- else
- abs_timeout_ns = current_ns + _timeout;
- }
-
/* The gem_syncobj_wait ioctl may return early due to an inherent
* limitation in the way it computes timeouts. Loop until we've actually
* passed the timeout.
@@ -665,6 +672,67 @@ done:
return result;
}
+static VkResult
+anv_wait_for_fences(struct anv_device *device,
+ uint32_t fenceCount,
+ const VkFence *pFences,
+ bool waitAll,
+ uint64_t abs_timeout)
+{
+ VkResult result = VK_SUCCESS;
+
+ if (fenceCount <= 1 || waitAll) {
+ for (uint32_t i = 0; i < fenceCount; i++) {
+ ANV_FROM_HANDLE(anv_fence, fence, pFences[i]);
+ switch (fence->permanent.type) {
+ case ANV_FENCE_TYPE_BO:
+ result = anv_wait_for_bo_fences(
+ device, 1, &pFences[i], true,
+ anv_get_relative_timeout(abs_timeout));
+ break;
+ case ANV_FENCE_TYPE_SYNCOBJ:
+ result = anv_wait_for_syncobj_fences(device, 1, &pFences[i],
+ true, abs_timeout);
+ break;
+ case ANV_FENCE_TYPE_NONE:
+ result = VK_SUCCESS;
+ break;
+ }
+ if (result != VK_SUCCESS)
+ return result;
+ }
+ } else {
+ while (gettime_ns() < abs_timeout) {
+ for (uint32_t i = 0; i < fenceCount; i++) {
+ if (anv_wait_for_fences(device, 1, &pFences[i], true, 0) == VK_SUCCESS)
+ return VK_SUCCESS;
+ }
+ }
+ result = VK_TIMEOUT;
+ }
+ return result;
+}
+
+static bool anv_all_fences_syncobj(uint32_t fenceCount, const VkFence *pFences)
+{
+ for (uint32_t i = 0; i < fenceCount; ++i) {
+ ANV_FROM_HANDLE(anv_fence, fence, pFences[i]);
+ if (fence->permanent.type != ANV_FENCE_TYPE_SYNCOBJ)
+ return false;
+ }
+ return true;
+}
+
+static bool anv_all_fences_bo(uint32_t fenceCount, const VkFence *pFences)
+{
+ for (uint32_t i = 0; i < fenceCount; ++i) {
+ ANV_FROM_HANDLE(anv_fence, fence, pFences[i]);
+ if (fence->permanent.type != ANV_FENCE_TYPE_BO)
+ return false;
+ }
+ return true;
+}
+
VkResult anv_WaitForFences(
VkDevice _device,
uint32_t fenceCount,
@@ -677,12 +745,15 @@ VkResult anv_WaitForFences(
if (unlikely(device->lost))
return VK_ERROR_DEVICE_LOST;
- if (device->instance->physicalDevice.has_syncobj_ wait) {
+ if (anv_all_fences_syncobj(fenceCount, pFences)) {
return anv_wait_for_syncobj_fences(device, fenceCount, pFences,
- waitAll, timeout);
- } else {
+ waitAll, anv_get_absolute_timeout(timeout));
+ } else if (anv_all_fences_bo(fenceCount, pFences)) {
return anv_wait_for_bo_fences(device, fenceCount, pFences,
waitAll, timeout);
+ } else {
+ return anv_wait_for_fences(device, fenceCount, pFences,
+ waitAll, anv_get_absolute_timeout(timeout));
}
}
--
2.17.1
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