[Mesa-dev] [PATCH] anv/query: ensure visibility of reset before copying query results

[Iago Toral Quiroga]

Specifically, vkCmdCopyQueryPoolResults is required to see the effect
of a previous vkCmdResetQueryPool. This may not work currently when
query execution is still on going, as some of the queries may become
available asynchronously after the reset.

Fixes new CTS tests:
dEQP-VK.query_pool.statistics_query.reset_before_copy.*
---

Jason, do you have any better ideas?

 src/intel/vulkan/genX_query.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/intel/vulkan/genX_query.c b/src/intel/vulkan/genX_query.c
index 146435c3f8f..08b013f6351 100644
--- a/src/intel/vulkan/genX_query.c
+++ b/src/intel/vulkan/genX_query.c
@@ -383,6 +383,19 @@ void genX(CmdResetQueryPool)(
    ANV_FROM_HANDLE(anv_cmd_buffer, cmd_buffer, commandBuffer);
    ANV_FROM_HANDLE(anv_query_pool, pool, queryPool);
 
+   /* From the Vulkan spec:
+    *
+    *    "vkCmdCopyQueryPoolResults is guaranteed to see the effect of
+    *     previous uses of vkCmdResetQueryPool in the same queue, without
+    *     any additional synchronization. Thus, the results will always
+    *     reflect the most recent use of the query."
+    *
+    * So we need to make sure that any on-going queries are finished by
+    * the time we emit the reset.
+    */
+   cmd_buffer->state.pending_pipe_bits |= ANV_PIPE_CS_STALL_BIT;
+   genX(cmd_buffer_apply_pipe_flushes)(cmd_buffer);
+
    for (uint32_t i = 0; i < queryCount; i++) {
       anv_batch_emit(&cmd_buffer->batch, GENX(MI_STORE_DATA_IMM), sdm) {
          sdm.Address = anv_query_address(pool, firstQuery + i);
-- 
2.17.1