BSR (R64, R64) - Throughput and Uops (IACA 2.3)

With different registers for different operands

With 1 independent instruction

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

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 | bsr r8, r9
Total Num Of Uops: 1

With 12 independent instructions

Throughput Analysis Report
--------------------------
Block Throughput: 12.00 Cycles       Throughput Bottleneck: Backend. Port1

Port Binding In Cycles Per Iteration:
-------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |
-------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 12.0 | 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 | bsr r8, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr r10, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr r11, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr r12, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr r13, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr r14, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr rbx, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr rcx, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr rdx, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr rdi, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr rsi, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr rbp, r9
Total Num Of Uops: 12

With the same register for for different operands

With 1 independent instruction

Throughput Analysis Report
--------------------------
Block Throughput: 2.86 Cycles       Throughput Bottleneck: FrontEnd

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 | bsr r8, r8
Total Num Of Uops: 1

With 13 independent instructions

Throughput Analysis Report
--------------------------
Block Throughput: 13.00 Cycles       Throughput Bottleneck: Backend. Port1

Port Binding In Cycles Per Iteration:
-------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |
-------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 13.0 | 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 | bsr r8, r8
|   1    |           | 1.0 |           |           |     |     | CP | bsr r9, r9
|   1    |           | 1.0 |           |           |     |     | CP | bsr r10, r10
|   1    |           | 1.0 |           |           |     |     | CP | bsr r11, r11
|   1    |           | 1.0 |           |           |     |     | CP | bsr r12, r12
|   1    |           | 1.0 |           |           |     |     | CP | bsr r13, r13
|   1    |           | 1.0 |           |           |     |     | CP | bsr r14, r14
|   1    |           | 1.0 |           |           |     |     | CP | bsr rbx, rbx
|   1    |           | 1.0 |           |           |     |     | CP | bsr rcx, rcx
|   1    |           | 1.0 |           |           |     |     | CP | bsr rdx, rdx
|   1    |           | 1.0 |           |           |     |     | CP | bsr rdi, rdi
|   1    |           | 1.0 |           |           |     |     | CP | bsr rsi, rsi
|   1    |           | 1.0 |           |           |     |     | CP | bsr rbp, rbp
Total Num Of Uops: 13