OV - exec - Loop 7

0x40fc9c ADD	X0, X4, #1

0x40fca0 ADD	X6, X4, #2

0x40fca4 STR	D0, [X27, X4,LSL #3]    [8]

0x40fca8 ADD	X1, X4, #3

0x40fcac ADD	X5, X4, #4

0x40fcb0 STR	D0, [X27, X0,LSL #3]    [6]

0x40fcb4 ADD	X7, X4, #5

0x40fcb8 ADD	X8, X4, #6

0x40fcbc STR	D0, [X27, X6,LSL #3]    [2]

0x40fcc0 ADD	X9, X4, #7

0x40fcc4 ADD	X4, X4, #8

0x40fcc8 STR	D0, [X27, X1,LSL #3]    [7]

0x40fccc STR	D0, [X27, X5,LSL #3]    [1]

0x40fcd0 STR	D0, [X27, X7,LSL #3]    [3]

0x40fcd4 STR	D0, [X27, X8,LSL #3]    [4]

0x40fcd8 STR	D0, [X27, X9,LSL #3]    [5]

0x40fcdc CMP	X17, X9

0x40fce0 B.NE	40fc9c

/home/hbollore/qaas-runs/171-233-5044/intel/AMG/build/AMG/AMG/test/amg.c: 317 - 318

--------------------------------------------------------------------------------

317:    for (i = 0; i < local_num_rows; i++)

318:       values[i] = 1.0;

Coverage (%)	Name	Source Location	Module

Path /

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.00
CQA speedup if fully vectorized	4.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.78
Bottlenecks	P6, P7, P10, P11,
Function	main
Source	amg.c:317-318
Source loop unroll info	not unrolled or unrolled with no peel/tail loop
Source loop unroll confidence level	max
Unroll/vectorization loop type	NA
Unroll factor	NA
CQA cycles	4.00
CQA cycles if no scalar integer	4.00
CQA cycles if FP arith vectorized	4.00
CQA cycles if fully vectorized	1.00
Front-end cycles	2.25
DIV/SQRT cycles	0.50
P0 cycles	0.50
P1 cycles	2.25
P2 cycles	2.25
P3 cycles	2.25
P4 cycles	2.25
P5 cycles	4.00
P6 cycles	4.00
P7 cycles	0.00
P8 cycles	0.00
P9 cycles	4.00
P10 cycles	4.00
P11 cycles	0.00
P12 cycles	0.00
P13 cycles	0.00
P14 cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	18.00
Nb uops	18.00
Nb loads	NA
Nb stores	8.00
Nb stack references	0.00
FLOP/cycle	0.00
Nb FLOP add-sub	0.00
Nb FLOP mul	0.00
Nb FLOP fma	0.00
Nb FLOP div	0.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	16.00
Bytes prefetched	0.00
Bytes loaded	0.00
Bytes stored	64.00
Stride 0	NA
Stride 1	NA
Stride n	NA
Stride unknown	NA
Stride indirect	NA
Vectorization ratio all	0.00
Vectorization ratio load	NA
Vectorization ratio store	0.00
Vectorization ratio mul	NA
Vectorization ratio add_sub	NA
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	NA
Vector-efficiency ratio all	25.00
Vector-efficiency ratio load	NA
Vector-efficiency ratio store	25.00
Vector-efficiency ratio mul	NA
Vector-efficiency ratio add_sub	NA
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	NA

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.00
CQA speedup if fully vectorized	4.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.78
Bottlenecks	P6, P7, P10, P11,
Function	main
Source	amg.c:317-318
Source loop unroll info	not unrolled or unrolled with no peel/tail loop
Source loop unroll confidence level	max
Unroll/vectorization loop type	NA
Unroll factor	NA
CQA cycles	4.00
CQA cycles if no scalar integer	4.00
CQA cycles if FP arith vectorized	4.00
CQA cycles if fully vectorized	1.00
Front-end cycles	2.25
DIV/SQRT cycles	0.50
P0 cycles	0.50
P1 cycles	2.25
P2 cycles	2.25
P3 cycles	2.25
P4 cycles	2.25
P5 cycles	4.00
P6 cycles	4.00
P7 cycles	0.00
P8 cycles	0.00
P9 cycles	4.00
P10 cycles	4.00
P11 cycles	0.00
P12 cycles	0.00
P13 cycles	0.00
P14 cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	18.00
Nb uops	18.00
Nb loads	NA
Nb stores	8.00
Nb stack references	0.00
FLOP/cycle	0.00
Nb FLOP add-sub	0.00
Nb FLOP mul	0.00
Nb FLOP fma	0.00
Nb FLOP div	0.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	16.00
Bytes prefetched	0.00
Bytes loaded	0.00
Bytes stored	64.00
Stride 0	NA
Stride 1	NA
Stride n	NA
Stride unknown	NA
Stride indirect	NA
Vectorization ratio all	0.00
Vectorization ratio load	NA
Vectorization ratio store	0.00
Vectorization ratio mul	NA
Vectorization ratio add_sub	NA
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	NA
Vector-efficiency ratio all	25.00
Vector-efficiency ratio load	NA
Vector-efficiency ratio store	25.00
Vector-efficiency ratio mul	NA
Vector-efficiency ratio add_sub	NA
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	NA

Path /

Average path: Display a virtual path defined by average values of all real paths

Function	main
Source file and lines	amg.c:317-318
Module	exec

The loop is defined in /home/hbollore/qaas-runs/171-233-5044/intel/AMG/build/AMG/AMG/test/amg.c:317-318.

The related source loop is not unrolled or unrolled with no peel/tail loop.

gain
potential
hint
expert

Vectorization

Your loop is not vectorized. 4 data elements could be processed at once in vector registers. By vectorizing your loop, you can lower the cost of an iteration from 4.00 to 1.00 cycles (4.00x speedup).

Details

All VPU instructions are used in scalar version (process only one data element in vector registers). Since your execution units are vector units, only a vectorized loop can use their full power.

Workaround

Try another compiler or update/tune your current one:
- recompile with fassociative-math (included in Ofast or ffast-math) to extend loop vectorization to FP reductions.
Remove inter-iterations dependences from your loop and make it unit-stride:
- If your arrays have 2 or more dimensions, check whether elements are accessed contiguously and, otherwise, try to permute loops accordingly: C storage order is row-major: for(i) for(j) a[j][i] = b[j][i]; (slow, non stride 1) => for(i) for(j) a[i][j] = b[i][j]; (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): for(i) a[i].x = b[i].x; (slow, non stride 1) => for(i) a.x[i] = b.x[i]; (fast, stride 1)

No data for this section

Matching between your loop (in the source code) and the binary loop

The binary loop does not contain any FP arithmetical operations. The binary loop is storing 64 bytes.

General properties

nb instructions	18
loop length	72
nb stack references	0

Front-end

FIT IN UOP CACHE

front end

2.25 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	2.25	2.25	2.25	2.25	4.00	4.00	0.00	0.00	4.00	4.00	0.00	0.00	0.00
cycles	0.50	0.50	2.25	2.25	2.25	2.25	4.00	4.00	0.00	0.00	4.00	4.00	0.00	0.00	0.00

Execution ports to units layout:

P0:
P1:
P2: ALU
P3: ALU
P4: ALU
P5: ALU
P6 (128 bits): VPU, FP store data, ALU, DIV/SQRT
P7 (128 bits): VPU, ALU, FP store data
P8 (128 bits): VPU, ALU, DIV/SQRT
P9 (128 bits): ALU, VPU
P10 (256 bits): store address, load
P11 (256 bits): store address, load
P12 (256 bits): load
P13 (64 bits): store data
P14 (64 bits): store data

Cycles executing div or sqrt instructions	NA
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	2.25
Data deps.	1.00
Overall L1	4.00

Vectorization ratios

all	0%
load	NA (no load vectorizable/vectorized instructions)
store	0%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	NA (no add-sub vectorizable/vectorized instructions)
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 4.00 cycles. At this rate:

33% of peak store performance is reached (16.00 out of 48.00 bytes stored per cycle (GB/s @ 1GHz))

ASM code

In the binary file, the address of the loop is: 40fc9c

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P10	P11	Latency	Recip. throughput
ADD X0, X4, #1	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X6, X4, #2	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X4,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
ADD X1, X4, #3	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X5, X4, #4	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X0,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
ADD X7, X4, #5	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X8, X4, #6	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X6,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
ADD X9, X4, #7	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X4, X4, #8	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X1,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X5,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X7,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X8,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X9,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
CMP X17, X9	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.33
B.NE 40fc9c <main+0x49c>	1	0.50	0.50	0	0	0	0	0	0	0	0	1	0.50

Function	main
Source file and lines	amg.c:317-318
Module	exec

The loop is defined in /home/hbollore/qaas-runs/171-233-5044/intel/AMG/build/AMG/AMG/test/amg.c:317-318.

The related source loop is not unrolled or unrolled with no peel/tail loop.

gain
potential
hint
expert

Vectorization

Your loop is not vectorized. 4 data elements could be processed at once in vector registers. By vectorizing your loop, you can lower the cost of an iteration from 4.00 to 1.00 cycles (4.00x speedup).

Details

All VPU instructions are used in scalar version (process only one data element in vector registers). Since your execution units are vector units, only a vectorized loop can use their full power.

Workaround

Try another compiler or update/tune your current one:
- recompile with fassociative-math (included in Ofast or ffast-math) to extend loop vectorization to FP reductions.
Remove inter-iterations dependences from your loop and make it unit-stride:
- If your arrays have 2 or more dimensions, check whether elements are accessed contiguously and, otherwise, try to permute loops accordingly: C storage order is row-major: for(i) for(j) a[j][i] = b[j][i]; (slow, non stride 1) => for(i) for(j) a[i][j] = b[i][j]; (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): for(i) a[i].x = b[i].x; (slow, non stride 1) => for(i) a.x[i] = b.x[i]; (fast, stride 1)

No data for this section

Matching between your loop (in the source code) and the binary loop

The binary loop does not contain any FP arithmetical operations. The binary loop is storing 64 bytes.

General properties

nb instructions	18
loop length	72
nb stack references	0

Front-end

FIT IN UOP CACHE

front end

2.25 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	2.25	2.25	2.25	2.25	4.00	4.00	0.00	0.00	4.00	4.00	0.00	0.00	0.00
cycles	0.50	0.50	2.25	2.25	2.25	2.25	4.00	4.00	0.00	0.00	4.00	4.00	0.00	0.00	0.00

Execution ports to units layout:

P0:
P1:
P2: ALU
P3: ALU
P4: ALU
P5: ALU
P6 (128 bits): VPU, FP store data, ALU, DIV/SQRT
P7 (128 bits): VPU, ALU, FP store data
P8 (128 bits): VPU, ALU, DIV/SQRT
P9 (128 bits): ALU, VPU
P10 (256 bits): store address, load
P11 (256 bits): store address, load
P12 (256 bits): load
P13 (64 bits): store data
P14 (64 bits): store data

Cycles executing div or sqrt instructions	NA
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	2.25
Data deps.	1.00
Overall L1	4.00

Vectorization ratios

all	0%
load	NA (no load vectorizable/vectorized instructions)
store	0%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	NA (no add-sub vectorizable/vectorized instructions)
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 4.00 cycles. At this rate:

33% of peak store performance is reached (16.00 out of 48.00 bytes stored per cycle (GB/s @ 1GHz))

ASM code

In the binary file, the address of the loop is: 40fc9c

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P10	P11	Latency	Recip. throughput
ADD X0, X4, #1	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X6, X4, #2	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X4,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
ADD X1, X4, #3	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X5, X4, #4	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X0,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
ADD X7, X4, #5	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X8, X4, #6	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X6,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
ADD X9, X4, #7	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
ADD X4, X4, #8	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.25
STR D0, [X27, X1,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X5,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X7,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X8,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
STR D0, [X27, X9,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0.50	0.50	2	0.50
CMP X17, X9	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	1	0.33
B.NE 40fc9c <main+0x49c>	1	0.50	0.50	0	0	0	0	0	0	0	0	1	0.50

Report Configuration

Vectorization

Details

Workaround

Matching between your loop (in the source code) and the binary loop

General properties

Front-end

Back-end

Cycles summary

Vectorization ratios

Cycles and memory resources usage

ASM code

Vectorization

Details

Workaround

Matching between your loop (in the source code) and the binary loop

General properties

Front-end

Back-end

Cycles summary

Vectorization ratios

Cycles and memory resources usage

ASM code