mesa: Add SSE 4.1 optimisation for glDrawElements.

Makes use of SSE 4.1 to speed up compute of min and max elements.

Callgrind cpu usage results from pts benchmarks:

Openarena 0.8.8: 3.67% -> 1.03%
UrbanTerror: 2.36% -> 0.81%

V5:
- actually make use of the optimisation in android (Emil Velikov)
- set a better array size limit for using SSE and added TODO

V4:
- fixed bugs with incrementing pointer and updating counters

V3:
- Removed sse_minmax.c from Makefile.sources
- handle the first few values without SSE until the pointer is aligned
 and use _mm_load_si128 rather than _mm_loadu_si128
- guard the call to the SSE code better at build time

V2:
- removed GL* types
- use _mm_store_si128() rather than _mm_store_ps()
- add runtime check for SSE
- use aligned attribute for local mix/max
- bunch of tidyups

Reviewed-by: Juha-Pekka Heikkila <[email protected]>
Reviewed-by: Matt Turner <[email protected]>
Signed-off-by: Timothy Arceri <[email protected]>

1 files changed, 97 insertions, 0 deletions

diff --git a/src/mesa/main/sse_minmax.c b/src/mesa/main/sse_minmax.c
new file mode 100644
index 00000000000..222ac14542e
--- /dev/null
+++ b/src/mesa/main/sse_minmax.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright © 2014 Timothy Arceri
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Author:
+ *    Timothy Arceri <[email protected]>
+ *
+ */
+
+#ifdef __SSE4_1__
+#include "main/sse_minmax.h"
+#include <smmintrin.h>
+#include <stdint.h>
+
+void
+_mesa_uint_array_min_max(const unsigned *ui_indices, unsigned *min_index,
+                         unsigned *max_index, const unsigned count)
+{
+   unsigned max_ui = 0;
+   unsigned min_ui = ~0U;
+   unsigned i = 0;
+   unsigned aligned_count = count;
+
+   /* handle the first few values without SSE until the pointer is aligned */
+   while (((uintptr_t)ui_indices & 15) && aligned_count) {
+      if (*ui_indices > max_ui)
+         max_ui = *ui_indices;
+      if (*ui_indices < min_ui)
+         min_ui = *ui_indices;
+
+      aligned_count--;
+      ui_indices++;
+   }
+
+   /* TODO: The actual threshold for SSE begin useful may be higher than 8.
+    * Some careful microbenchmarks and measurement are required to
+    * find the actual tipping point.
+    */
+   if (aligned_count >= 8) {
+      unsigned max_arr[4] __attribute__ ((aligned (16)));
+      unsigned min_arr[4] __attribute__ ((aligned (16)));
+      unsigned vec_count;
+      __m128i max_ui4 = _mm_setzero_si128();
+      __m128i min_ui4 = _mm_set1_epi32(~0U);
+      __m128i ui_indices4;
+      __m128i *ui_indices_ptr;
+
+      vec_count = aligned_count & ~0x3;
+      ui_indices_ptr = (__m128i *)ui_indices;
+      for (i = 0; i < vec_count / 4; i++) {
+         ui_indices4 = _mm_load_si128(&ui_indices_ptr[i]);
+         max_ui4 = _mm_max_epu32(ui_indices4, max_ui4);
+         min_ui4 = _mm_min_epu32(ui_indices4, min_ui4);
+      }
+
+      _mm_store_si128((__m128i *)max_arr, max_ui4);
+      _mm_store_si128((__m128i *)min_arr, min_ui4);
+
+      for (i = 0; i < 4; i++) {
+         if (max_arr[i] > max_ui)
+            max_ui = max_arr[i];
+         if (min_arr[i] < min_ui)
+            min_ui = min_arr[i];
+      }
+      i = vec_count;
+   }
+
+   for (; i < aligned_count; i++) {
+      if (ui_indices[i] > max_ui)
+         max_ui = ui_indices[i];
+      if (ui_indices[i] < min_ui)
+         min_ui = ui_indices[i];
+   }
+
+   *min_index = min_ui;
+   *max_index = max_ui;
+}
+
+#endif