BSR (R64, M64) - Port Usage (IACA 2.1)


With blocking instructions for port '1':

Throughput Analysis Report
--------------------------
Block Throughput: 11.00 Cycles       Throughput Bottleneck: Port1

Port Binding In Cycles Per Iteration:
---------------------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |  6   |  7   |
---------------------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 11.0 | 0.5    0.5  | 0.5    0.5  | 0.0  | 0.0  | 0.0  | 0.0  |
---------------------------------------------------------------------------------------


| Num Of |                    Ports pressure in cycles                     |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |  6  |  7  |    |
---------------------------------------------------------------------------------
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm0, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm2, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm3, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm4, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm5, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm6, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm7, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm8, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm9, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm10, xmm1
|   2^   |           | 1.0 | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | bsr r8, qword ptr [r14]
Total Num Of Uops: 12
⇨ One μop that can only use port '1'

With blocking instructions for ports {'2', '3'}:

Throughput Analysis Report
--------------------------
Block Throughput: 5.50 Cycles       Throughput Bottleneck: PORT2_AGU, Port2_DATA, PORT3_AGU, Port3_DATA

Port Binding In Cycles Per Iteration:
---------------------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |  6   |  7   |
---------------------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 1.0  | 5.5    5.5  | 5.5    5.5  | 0.0  | 0.0  | 0.0  | 0.0  |
---------------------------------------------------------------------------------------


| Num Of |                    Ports pressure in cycles                     |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |  6  |  7  |    |
---------------------------------------------------------------------------------
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm0, xmmword ptr [r14+0x40]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm1, xmmword ptr [r14+0x50]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm2, xmmword ptr [r14+0x60]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm3, xmmword ptr [r14+0x70]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm4, xmmword ptr [r14+0x80]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm5, xmmword ptr [r14+0x90]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm6, xmmword ptr [r14+0xa0]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm7, xmmword ptr [r14+0xb0]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm8, xmmword ptr [r14+0xc0]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm9, xmmword ptr [r14+0xd0]
|   2^   |           | 1.0 | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | bsr r8, qword ptr [r14]
Total Num Of Uops: 12
⇨ One μop that can only use ports {'2', '3'}

With an indexed addressing mode


With blocking instructions for port '1':

Throughput Analysis Report
--------------------------
Block Throughput: 11.00 Cycles       Throughput Bottleneck: Port1

Port Binding In Cycles Per Iteration:
---------------------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |  6   |  7   |
---------------------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 11.0 | 0.5    0.5  | 0.5    0.5  | 0.0  | 0.0  | 0.0  | 0.0  |
---------------------------------------------------------------------------------------


| Num Of |                    Ports pressure in cycles                     |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |  6  |  7  |    |
---------------------------------------------------------------------------------
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm0, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm2, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm3, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm4, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm5, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm6, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm7, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm8, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm9, xmm1
|   1    |           | 1.0 |           |           |     |     |     |     | CP | addpd xmm10, xmm1
|   2    |           | 1.0 | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | bsr r8, qword ptr [r14+r13*1]
Total Num Of Uops: 12
⇨ One μop that can only use port '1'

With blocking instructions for ports {'2', '3'}:

Throughput Analysis Report
--------------------------
Block Throughput: 5.50 Cycles       Throughput Bottleneck: PORT2_AGU, Port2_DATA, PORT3_AGU, Port3_DATA

Port Binding In Cycles Per Iteration:
---------------------------------------------------------------------------------------
|  Port  |  0   -  DV  |  1   |  2   -  D   |  3   -  D   |  4   |  5   |  6   |  7   |
---------------------------------------------------------------------------------------
| Cycles | 0.0    0.0  | 1.0  | 5.5    5.5  | 5.5    5.5  | 0.0  | 0.0  | 0.0  | 0.0  |
---------------------------------------------------------------------------------------


| Num Of |                    Ports pressure in cycles                     |    |
|  Uops  |  0  - DV  |  1  |  2  -  D  |  3  -  D  |  4  |  5  |  6  |  7  |    |
---------------------------------------------------------------------------------
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm0, xmmword ptr [r14+0x40]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm1, xmmword ptr [r14+0x50]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm2, xmmword ptr [r14+0x60]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm3, xmmword ptr [r14+0x70]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm4, xmmword ptr [r14+0x80]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm5, xmmword ptr [r14+0x90]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm6, xmmword ptr [r14+0xa0]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm7, xmmword ptr [r14+0xb0]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm8, xmmword ptr [r14+0xc0]
|   1^   |           |     | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | lddqu xmm9, xmmword ptr [r14+0xd0]
|   2    |           | 1.0 | 0.5   0.5 | 0.5   0.5 |     |     |     |     | CP | bsr r8, qword ptr [r14+r13*1]
Total Num Of Uops: 12
⇨ One μop that can only use ports {'2', '3'}