CRC32 (R64, R64) - Throughput and Uops (IACA 2.2)


With different registers for different operands

With 1 independent instruction

Throughput Analysis Report
--------------------------
Block Throughput: 3.00 Cycles       Throughput Bottleneck: Dependency chains (possibly between iterations)

Port Binding In Cycles Per Iteration:
-------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |
-------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 1.0  | 0.0    0.0  | 0.0    0.0  | 0.0  | 0.0  |
-------------------------------------------------------------------------


| Num Of |              Ports pressure in cycles               |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |    |
---------------------------------------------------------------------
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r8, r9
Total Num Of Uops: 1

With 9 independent instructions


Throughput Analysis Report
--------------------------
Block Throughput: 12.00 Cycles       Throughput Bottleneck: Dependency chains (possibly between iterations)

Port Binding In Cycles Per Iteration:
-------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |
-------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 9.0  | 0.0    0.0  | 0.0    0.0  | 0.0  | 0.0  |
-------------------------------------------------------------------------


| Num Of |              Ports pressure in cycles               |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |    |
---------------------------------------------------------------------
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r8, r9
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r10, r9
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r11, r9
|   1    |           | 1.0 |           |           |     |     |    | crc32 r12, r9
|   1    |           | 1.0 |           |           |     |     | CP | crc32 rbx, r9
|   1    |           | 1.0 |           |           |     |     | CP | crc32 rcx, r9
|   1    |           | 1.0 |           |           |     |     | CP | crc32 rdx, r9
|   1    |           | 1.0 |           |           |     |     |    | crc32 rdi, r9
|   1    |           | 1.0 |           |           |     |     |    | crc32 rsi, r9
Total Num Of Uops: 9

With the same register for for different operands

With 1 independent instruction

Throughput Analysis Report
--------------------------
Block Throughput: 3.00 Cycles       Throughput Bottleneck: Dependency chains (possibly between iterations)

Port Binding In Cycles Per Iteration:
-------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |
-------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 1.0  | 0.0    0.0  | 0.0    0.0  | 0.0  | 0.0  |
-------------------------------------------------------------------------


| Num Of |              Ports pressure in cycles               |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |    |
---------------------------------------------------------------------
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r8, r8
Total Num Of Uops: 1

With 10 independent instructions


Throughput Analysis Report
--------------------------
Block Throughput: 12.00 Cycles       Throughput Bottleneck: Dependency chains (possibly between iterations)

Port Binding In Cycles Per Iteration:
-------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |
-------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 10.0 | 0.0    0.0  | 0.0    0.0  | 0.0  | 0.0  |
-------------------------------------------------------------------------


| Num Of |              Ports pressure in cycles               |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |    |
---------------------------------------------------------------------
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r8, r8
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r9, r9
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r10, r10
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r11, r11
|   1    |           | 1.0 |           |           |     |     |    | crc32 r12, r12
|   1    |           | 1.0 |           |           |     |     |    | crc32 rbx, rbx
|   1    |           | 1.0 |           |           |     |     |    | crc32 rcx, rcx
|   1    |           | 1.0 |           |           |     |     |    | crc32 rdx, rdx
|   1    |           | 1.0 |           |           |     |     |    | crc32 rdi, rdi
|   1    |           | 1.0 |           |           |     |     |    | crc32 rsi, rsi
Total Num Of Uops: 10

With the -no_interiteration flag

Throughput Analysis Report
--------------------------
Block Throughput: 1.00 Cycles       Throughput Bottleneck: Port1

Port Binding In Cycles Per Iteration:
-------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |
-------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 1.0  | 0.0    0.0  | 0.0    0.0  | 0.0  | 0.0  |
-------------------------------------------------------------------------


| Num Of |              Ports pressure in cycles               |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |    |
---------------------------------------------------------------------
|   1    |           | 1.0 |           |           |     |     | CP | crc32 r8, r9
Total Num Of Uops: 1