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authorFrancisco Jerez <[email protected]>2013-11-01 11:29:13 -0700
committerFrancisco Jerez <[email protected]>2013-11-04 12:12:38 -0800
commit35fe7ed7d3c45f5263ae42bcedecc00ba6adf91d (patch)
treeccd10ca5c2497e408b319930f955da99724e755c /src/mesa/drivers/dri
parentba885c30c74f9efc94743d4582d30a0e70924b97 (diff)
i965/gen7: Add instruction latency estimates for untyped atomics and reads.
The latency information has been obtained empirically from measurements taken on Haswell and Ivy Bridge. Acked-by: Paul Berry <[email protected]> Reviewed-by: Matt Turner <[email protected]>
Diffstat (limited to 'src/mesa/drivers/dri')
-rw-r--r--src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp39
1 files changed, 39 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
index fe0de080544..5a425133a9d 100644
--- a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
+++ b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
@@ -352,6 +352,45 @@ schedule_node::set_latency_gen7(bool is_haswell)
* then around 140. Presumably this is cache hit vs miss.
*/
latency = 50;
+ case SHADER_OPCODE_UNTYPED_ATOMIC:
+ /* Test code:
+ * mov(8) g112<1>ud 0x00000000ud { align1 WE_all 1Q };
+ * mov(1) g112.7<1>ud g1.7<0,1,0>ud { align1 WE_all };
+ * mov(8) g113<1>ud 0x00000000ud { align1 WE_normal 1Q };
+ * send(8) g4<1>ud g112<8,8,1>ud
+ * data (38, 5, 6) mlen 2 rlen 1 { align1 WE_normal 1Q };
+ *
+ * Running it 100 times as fragment shader on a 128x128 quad
+ * gives an average latency of 13867 cycles per atomic op,
+ * standard deviation 3%. Note that this is a rather
+ * pessimistic estimate, the actual latency in cases with few
+ * collisions between threads and favorable pipelining has been
+ * seen to be reduced by a factor of 100.
+ */
+ latency = 14000;
+ break;
+
+ case SHADER_OPCODE_UNTYPED_SURFACE_READ:
+ /* Test code:
+ * mov(8) g112<1>UD 0x00000000UD { align1 WE_all 1Q };
+ * mov(1) g112.7<1>UD g1.7<0,1,0>UD { align1 WE_all };
+ * mov(8) g113<1>UD 0x00000000UD { align1 WE_normal 1Q };
+ * send(8) g4<1>UD g112<8,8,1>UD
+ * data (38, 6, 5) mlen 2 rlen 1 { align1 WE_normal 1Q };
+ * .
+ * . [repeats 8 times]
+ * .
+ * mov(8) g112<1>UD 0x00000000UD { align1 WE_all 1Q };
+ * mov(1) g112.7<1>UD g1.7<0,1,0>UD { align1 WE_all };
+ * mov(8) g113<1>UD 0x00000000UD { align1 WE_normal 1Q };
+ * send(8) g4<1>UD g112<8,8,1>UD
+ * data (38, 6, 5) mlen 2 rlen 1 { align1 WE_normal 1Q };
+ *
+ * Running it 100 times as fragment shader on a 128x128 quad
+ * gives an average latency of 583 cycles per surface read,
+ * standard deviation 0.9%.
+ */
+ latency = is_haswell ? 300 : 600;
break;
default: