[Mesa-dev] [PATCH 5/7] i965/fs: move the fs_reg::smear() from get_timestamp() to the callers

[Emil Velikov]

We're about to reuse get_timestamp() for the nir_intrinsic_shader_clock.
In the latter the generalisation does not apply, so move the smear()
where needed. This also makes the function analogous to the vec4 one.

v2: Tweak the comment - The caller -> We (Matt, Connor).

Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
---

Connor,

The diff might be a bit hard to read, but the patch does remove the 
comment from get_timestamp(), If you guys prefer I can also drop it from 
shader_time_begin() and(?) delay the smear until emit_shader_time_end().

-Emil

 src/mesa/drivers/dri/i965/brw_fs.cpp | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index a2fd441..93bb55d 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -521,7 +521,15 @@ fs_visitor::get_timestamp(const fs_builder &bld)
     */
    bld.group(4, 0).exec_all().MOV(dst, ts);
 
-   /* The caller wants the low 32 bits of the timestamp.  Since it's running
+   return dst;
+}
+
+void
+fs_visitor::emit_shader_time_begin()
+{
+   shader_start_time = get_timestamp(bld.annotate("shader time start"));
+
+   /* We want only the low 32 bits of the timestamp.  Since it's running
     * at the GPU clock rate of ~1.2ghz, it will roll over every ~3 seconds,
     * which is plenty of time for our purposes.  It is identical across the
     * EUs, but since it's tracking GPU core speed it will increment at a
@@ -531,15 +539,7 @@ fs_visitor::get_timestamp(const fs_builder &bld)
     * else that might disrupt timing) by setting smear to 2 and checking if
     * that field is != 0.
     */
-   dst.set_smear(0);
-
-   return dst;
-}
-
-void
-fs_visitor::emit_shader_time_begin()
-{
-   shader_start_time = get_timestamp(bld.annotate("shader time start"));
+   shader_start_time.set_smear(0);
 }
 
 void
@@ -553,6 +553,18 @@ fs_visitor::emit_shader_time_end()
 
    fs_reg shader_end_time = get_timestamp(ibld);
 
+   /* We want only the low 32 bits of the timestamp.  Since it's running
+    * at the GPU clock rate of ~1.2ghz, it will roll over every ~3 seconds,
+    * which is plenty of time for our purposes.  It is identical across the
+    * EUs, but since it's tracking GPU core speed it will increment at a
+    * varying rate as render P-states change.
+    *
+    * The caller could also check if render P-states have changed (or anything
+    * else that might disrupt timing) by setting smear to 2 and checking if
+    * that field is != 0.
+    */
+   shader_end_time.set_smear(0);
+
    /* Check that there weren't any timestamp reset events (assuming these
     * were the only two timestamp reads that happened).
     */
-- 
2.6.1