OV - exec - Function main._omp

	Function: main._omp_fn.3	Module: exec	Source: stream.c:290-292	Coverage (incl. loops): 0.67% \| (excl. loops): 0.00%

/beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c: 290 - 292

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

290: #pragma omp parallel for

291:     for (j = 0; j < STREAM_ARRAY_SIZE; j++)

292: 		a[j] = 2.0E0 * a[j];

0x401bf0 PUSH	%RBP

0x401bf1 MOV	$0x401060,%RAX

0x401bfb MOV	%RSP,%RBP

0x401bfe PUSH	%RBX

0x401bff SUB	$0x8,%RSP

0x401c03 CALL	%RAX

0x401c05 MOVSXD	%EAX,%RBX

0x401c08 MOV	$0x401030,%RAX

0x401c12 CALL	%RAX

0x401c14 MOVSXD	%EAX,%RCX

0x401c17 MOV	$0x33450000,%EAX

0x401c1c CQTO

0x401c1e IDIV	%RBX

0x401c21 CMP	%RDX,%RCX

0x401c24 JL	401da0

0x401c2a IMUL	%RAX,%RCX

0x401c2e ADD	%RCX,%RDX

0x401c31 ADD	%RDX,%RAX

0x401c34 CMP	%RAX,%RDX

0x401c37 JGE	401d8c

0x401c3d MOV	$0x3349060e0,%RSI

0x401c47 LEA	(%RSI,%RAX,8),%R8

0x401c4b LEA	(%RSI,%RDX,8),%RDI

0x401c4f MOV	%R8,%R9

0x401c52 SUB	%RDI,%R9

0x401c55 SUB	$0x8,%R9

0x401c59 SHR	$0x3,%R9

0x401c5d INC	%R9

0x401c60 AND	$0x7,%R9D

0x401c64 JE	401d11

0x401c6a CMP	$0x1,%R9

0x401c6e JE	401cfa

0x401c74 CMP	$0x2,%R9

0x401c78 JE	401ce8

0x401c7a CMP	$0x3,%R9

0x401c7e JE	401cd6

0x401c80 CMP	$0x4,%R9

0x401c84 JE	401cc5

0x401c86 CMP	$0x5,%R9

0x401c8a JE	401cb4

0x401c8c CMP	$0x6,%R9

0x401c90 JE	401ca3

0x401c92 VMOVSD	(%RDI),%XMM0

0x401c96 ADD	$0x8,%RDI

0x401c9a VADDSD	%XMM0,%XMM0,%XMM1

0x401c9e VMOVSD	%XMM1,-0x8(%RDI)

0x401ca3 VMOVSD	(%RDI),%XMM2

0x401ca7 ADD	$0x8,%RDI

0x401cab VADDSD	%XMM2,%XMM2,%XMM3

0x401caf VMOVSD	%XMM3,-0x8(%RDI)

0x401cb4 VMOVSD	(%RDI),%XMM4

0x401cb8 ADD	$0x8,%RDI

0x401cbc VADDSD	%XMM4,%XMM4,%XMM5

0x401cc0 VMOVSD	%XMM5,-0x8(%RDI)

0x401cc5 VMOVSD	(%RDI),%XMM6

0x401cc9 ADD	$0x8,%RDI

0x401ccd VADDSD	%XMM6,%XMM6,%XMM7

0x401cd1 VMOVSD	%XMM7,-0x8(%RDI)

0x401cd6 VMOVSD	(%RDI),%XMM8

0x401cda ADD	$0x8,%RDI

0x401cde VADDSD	%XMM8,%XMM8,%XMM9

0x401ce3 VMOVSD	%XMM9,-0x8(%RDI)

0x401ce8 VMOVSD	(%RDI),%XMM10

0x401cec ADD	$0x8,%RDI

0x401cf0 VADDSD	%XMM10,%XMM10,%XMM11

0x401cf5 VMOVSD	%XMM11,-0x8(%RDI)

0x401cfa VMOVSD	(%RDI),%XMM12

0x401cfe ADD	$0x8,%RDI

0x401d02 VADDSD	%XMM12,%XMM12,%XMM13

0x401d07 VMOVSD	%XMM13,-0x8(%RDI)

0x401d0c CMP	%R8,%RDI

0x401d0f JE	401d8c

(4) 0x401d11 VMOVSD	(%RDI),%XMM14

(4) 0x401d15 VMOVSD	0x8(%RDI),%XMM0

(4) 0x401d1a VMOVSD	0x10(%RDI),%XMM2

(4) 0x401d1f VMOVSD	0x18(%RDI),%XMM4

(4) 0x401d24 VMOVSD	0x20(%RDI),%XMM6

(4) 0x401d29 VMOVSD	0x28(%RDI),%XMM8

(4) 0x401d2e VMOVSD	0x30(%RDI),%XMM10

(4) 0x401d33 VMOVSD	0x38(%RDI),%XMM12

(4) 0x401d38 VADDSD	%XMM14,%XMM14,%XMM15

(4) 0x401d3d VADDSD	%XMM0,%XMM0,%XMM1

(4) 0x401d41 VMOVSD	%XMM15,(%RDI)

(4) 0x401d45 VMOVSD	%XMM1,0x8(%RDI)

(4) 0x401d4a VADDSD	%XMM2,%XMM2,%XMM3

(4) 0x401d4e VADDSD	%XMM4,%XMM4,%XMM5

(4) 0x401d52 VMOVSD	%XMM3,0x10(%RDI)

(4) 0x401d57 VMOVSD	%XMM5,0x18(%RDI)

(4) 0x401d5c VADDSD	%XMM6,%XMM6,%XMM7

(4) 0x401d60 VADDSD	%XMM8,%XMM8,%XMM9

(4) 0x401d65 VMOVSD	%XMM7,0x20(%RDI)

(4) 0x401d6a VMOVSD	%XMM9,0x28(%RDI)

(4) 0x401d6f VADDSD	%XMM10,%XMM10,%XMM11

(4) 0x401d74 VADDSD	%XMM12,%XMM12,%XMM13

(4) 0x401d79 VMOVSD	%XMM11,0x30(%RDI)

(4) 0x401d7e VMOVSD	%XMM13,0x38(%RDI)

(4) 0x401d83 ADD	$0x40,%RDI

(4) 0x401d87 CMP	%R8,%RDI

(4) 0x401d8a JNE	401d11

0x401d8c MOV	-0x8(%RBP),%RBX

0x401d90 LEAVE

0x401d91 RET

0x401d92 NOPW	%CS:(%RAX,%RAX,1)

0x401d9d NOPL	(%RAX)

0x401da0 INC	%RAX

0x401da3 XOR	%EDX,%EDX

0x401da5 JMP	401c2a

0x401daa NOPW	(%RAX,%RAX,1)

Coverage (%)	Name	Source Location	Module
○98.94	gomp_thread_start	team.c:130	libgomp.so.1.0.0
○1.06	GOMP_parallel	libgomp.h:982	libgomp.so.1.0.0

min	med	avg	max

Percentile Index	10	20	30	40	50	60	70	80	90	100
Value

min	med	avg	max

Percentile Index	10	20	30	40	50	60	70	80	90	100
Value

Path /

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

The code analyzed by CQA in that panel excludes loops and represents 0.00% of application time for run gcc_8

Source file and lines	stream.c:290-292
Module	exec

The function is defined in /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290-292.

Warnings:
Ignoring paths for analysis

gain
potential
hint
expert

Code clean check

Detected a slowdown caused by scalar integer instructions (typically used for address computation). By removing them, you can lower the cost of an iteration from 13.50 to 6.17 cycles (2.19x speedup).

Workaround

Try to reorganize arrays of structures to structures of arrays
Consider to permute loops (see vectorization gain report)

Vectorization

Your function is not vectorized. Only 12% of vector register length is used (average across all SSE/AVX instructions). By vectorizing your function, you can lower the cost of an iteration from 13.50 to 3.00 cycles (4.50x speedup).

Details

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

Workaround

Try another compiler or update/tune your current one
Make array accesses unit-stride:
- If your function 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)

Execution units bottlenecks

Found no such bottlenecks but see expert reports for more complex bottlenecks.

No data for this section

CALL instructions

Detected function call instructions.

Details

Calling (and then returning from) a function prevents many compiler optimizations (like vectorization), breaks control flow (which reduces pipeline performance) and executes extra instructions to save/restore the registers used inside it, which is very expensive (dozens of cycles). Consider to inline small functions.

unknown: 2 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290

Complex instructions

Detected COMPLEX INSTRUCTIONS.

Details

These instructions generate more than one micro-operation and only one of them can be decoded during a cycle and the extra micro-operations increase pressure on execution units.

IDIV: 1 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290
LEAVE: 1 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290

Conversion instructions

Detected expensive conversion instructions.

Details

CQTO: 1 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290

Workaround

Avoid mixing data with different types. In particular, check if the type of constants is the same as array elements.

Type of elements and instruction set

7 SSE or AVX instructions are processing arithmetic or math operations on double precision FP elements in scalar mode (one at a time).

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

The binary function is composed of 7 FP arithmetical operations:

7: addition or subtraction

The binary function is loading 64 bytes (8 double precision FP elements). The binary function is storing 56 bytes (7 double precision FP elements).

Arithmetic intensity

Arithmetic intensity is 0.06 FP operations per loaded or stored byte.

General properties

nb instructions	81
nb uops	81
loop length	325
used x86 registers	10
used mmx registers	0
used xmm registers	14
used ymm registers	0
used zmm registers	0
nb stack references	1

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	13.50 cycles
front end	13.50 cycles

Back-end

	ALU0/BRU0	ALU1	ALU2	ALU3	BRU1	AGU0	AGU1	AGU2	FP0	FP1	FP2	FP3	FP4	FP5
uops	10.75	10.75	10.75	10.75	8.00	6.00	6.00	6.00	0.00	0.00	3.50	3.50	3.50	3.50
cycles	10.75	10.75	10.75	10.75	8.00	6.00	6.00	6.00	0.00	0.00	3.50	3.50	3.50	3.50

Execution ports to units layout:

ALU0/BRU0: ALU, BRU
ALU1: ALU
ALU2: ALU
ALU3: ALU
BRU1: BRU
AGU0 (256 bits): store address, load
AGU1 (256 bits): store address, load
AGU2 (256 bits): store address, load
FP0 (256 bits): VPU, DIV/SQRT
FP1 (256 bits): VPU, DIV/SQRT
FP2 (256 bits): VPU
FP3 (256 bits): VPU
FP4 (256 bits): FP store data
FP5 (256 bits): FP store data

Cycles executing div or sqrt instructions

7.00-12.00

Cycles summary

Front-end	13.50
Dispatch	10.75
DIV/SQRT	7.00-12.00
Overall L1	13.50

Vectorization ratios

INT

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

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

INT+FP

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

Vector efficiency ratios

INT

all	11%
load	12%
store	NA (no store vectorizable/vectorized instructions)
mul	12%
add-sub	12%
fma	NA (no fma vectorizable/vectorized instructions)
other	11%

all	12%
load	12%
store	12%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	12%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

INT+FP

all	12%
load	12%
store	12%
mul	12%
add-sub	12%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	12%
other	11%

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each call to the function takes 13.50 cycles. At this rate:

4% of peak load performance is reached (4.74 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
6% of peak store performance is reached (4.15 out of 64.00 bytes stored per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Performance is limited by instruction throughput (loading/decoding program instructions to execution core) (front-end is a bottleneck).

ASM code

In the binary file, the address of the function is: 401bf0

Instruction	Nb FU	ALU0/BRU0	ALU1	ALU2	ALU3	BRU1	AGU0	AGU1	AGU2	FP0	FP1	FP2	FP3	FP4	FP5	Latency	Recip. throughput	Vectorization
PUSH %RBP	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A
MOV $0x401060,%RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.33	N/A
MOV %RSP,%RBP	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.17	N/A
PUSH %RBX	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A
SUB $0x8,%RSP	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
CALL %RAX	2	0.50	0	0	0	0.50	0.33	0.33	0.33	0	0	0	0	0	0	0	2	N/A
MOVSXD %EAX,%RBX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (6.3%)
MOV $0x401030,%RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.33	N/A
CALL %RAX	2	0.50	0	0	0	0.50	0.33	0.33	0.33	0	0	0	0	0	0	0	2	N/A
MOVSXD %EAX,%RCX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (6.3%)
MOV $0x33450000,%EAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
CQTO																		scal (12.5%)
IDIV %RBX	2	2	0	0	0	0	0	0	0	0	0	0	0	0	0	9-19	7-12	scal (12.5%)
CMP %RDX,%RCX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JL 401da0 <main._omp_fn.3+0x1b0>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
IMUL %RAX,%RCX	1	0	1	0	0	0	0	0	0	0	0	0	0	0	0	3	1	scal (12.5%)
ADD %RCX,%RDX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
ADD %RDX,%RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
CMP %RAX,%RDX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JGE 401d8c <main._omp_fn.3+0x19c>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
MOV $0x3349060e0,%RSI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.33	N/A
LEA (%RSI,%RAX,8),%R8	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
LEA (%RSI,%RDX,8),%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
MOV %R8,%R9	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.17	scal (12.5%)
SUB %RDI,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
SUB $0x8,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
SHR $0x3,%R9	1	0	0.50	0.50	0	0	0	0	0	0	0	0	0	0	0	1	0.50	scal (12.5%)
INC %R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
AND $0x7,%R9D	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (6.3%)
JE 401d11 <main._omp_fn.3+0x121>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x1,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cfa <main._omp_fn.3+0x10a>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x2,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401ce8 <main._omp_fn.3+0xf8>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x3,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cd6 <main._omp_fn.3+0xe6>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x4,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cc5 <main._omp_fn.3+0xd5>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x5,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cb4 <main._omp_fn.3+0xc4>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x6,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401ca3 <main._omp_fn.3+0xb3>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
VMOVSD (%RDI),%XMM0	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM0,%XMM0,%XMM1	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM1,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM2	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM2,%XMM2,%XMM3	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM3,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM4	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM4,%XMM4,%XMM5	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM5,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM6	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM6,%XMM6,%XMM7	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM7,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM8	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM8,%XMM8,%XMM9	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM9,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM10	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM10,%XMM10,%XMM11	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM11,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM12	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM12,%XMM12,%XMM13	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM13,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
CMP %R8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401d8c <main._omp_fn.3+0x19c>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
MOV -0x8(%RBP),%RBX	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	3	0.33	scal (12.5%)
LEAVE	2	0.25	0.25	0.25	0.25	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	N/A
RET	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50	N/A
NOPW %CS:(%RAX,%RAX,1)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.09	N/A
NOPL (%RAX)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.09	N/A
INC %RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
XOR %EDX,%EDX	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.25	N/A
JMP 401c2a <main._omp_fn.3+0x3a>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	0	1	N/A
NOPW (%RAX,%RAX,1)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.09	N/A

The code analyzed by CQA in that panel excludes loops and represents 0.00% of application time for run gcc_8

Source file and lines	stream.c:290-292
Module	exec

gain
potential
hint
expert

Code clean check

Detected a slowdown caused by scalar integer instructions (typically used for address computation). By removing them, you can lower the cost of an iteration from 13.50 to 6.17 cycles (2.19x speedup).

Workaround

Try to reorganize arrays of structures to structures of arrays
Consider to permute loops (see vectorization gain report)

Vectorization

Details

Workaround

Try another compiler or update/tune your current one
Make array accesses unit-stride:
- If your function 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)

Execution units bottlenecks

Found no such bottlenecks but see expert reports for more complex bottlenecks.

No data for this section

CALL instructions

Detected function call instructions.

Details

unknown: 2 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290

Complex instructions

Detected COMPLEX INSTRUCTIONS.

Details

These instructions generate more than one micro-operation and only one of them can be decoded during a cycle and the extra micro-operations increase pressure on execution units.

IDIV: 1 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290
LEAVE: 1 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290

Conversion instructions

Detected expensive conversion instructions.

Details

CQTO: 1 occurrences►
- /beegfs/hackathon/users/eoseret/qaas_runs_test/gmz16.benchmarkcenter.megware.com/177-374-0012/stream-scale/build/stream-scale/src/stream.c:290

Workaround

Avoid mixing data with different types. In particular, check if the type of constants is the same as array elements.

Type of elements and instruction set

7 SSE or AVX instructions are processing arithmetic or math operations on double precision FP elements in scalar mode (one at a time).

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

The binary function is composed of 7 FP arithmetical operations:

7: addition or subtraction

The binary function is loading 64 bytes (8 double precision FP elements). The binary function is storing 56 bytes (7 double precision FP elements).

Arithmetic intensity

Arithmetic intensity is 0.06 FP operations per loaded or stored byte.

General properties

nb instructions	81
nb uops	81
loop length	325
used x86 registers	10
used mmx registers	0
used xmm registers	14
used ymm registers	0
used zmm registers	0
nb stack references	1

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	13.50 cycles
front end	13.50 cycles

Back-end

	ALU0/BRU0	ALU1	ALU2	ALU3	BRU1	AGU0	AGU1	AGU2	FP0	FP1	FP2	FP3	FP4	FP5
uops	10.75	10.75	10.75	10.75	8.00	6.00	6.00	6.00	0.00	0.00	3.50	3.50	3.50	3.50
cycles	10.75	10.75	10.75	10.75	8.00	6.00	6.00	6.00	0.00	0.00	3.50	3.50	3.50	3.50

Execution ports to units layout:

ALU0/BRU0: ALU, BRU
ALU1: ALU
ALU2: ALU
ALU3: ALU
BRU1: BRU
AGU0 (256 bits): store address, load
AGU1 (256 bits): store address, load
AGU2 (256 bits): store address, load
FP0 (256 bits): VPU, DIV/SQRT
FP1 (256 bits): VPU, DIV/SQRT
FP2 (256 bits): VPU
FP3 (256 bits): VPU
FP4 (256 bits): FP store data
FP5 (256 bits): FP store data

Cycles executing div or sqrt instructions

7.00-12.00

Cycles summary

Front-end	13.50
Dispatch	10.75
DIV/SQRT	7.00-12.00
Overall L1	13.50

Vectorization ratios

INT

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

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

INT+FP

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

Vector efficiency ratios

INT

all	11%
load	12%
store	NA (no store vectorizable/vectorized instructions)
mul	12%
add-sub	12%
fma	NA (no fma vectorizable/vectorized instructions)
other	11%

all	12%
load	12%
store	12%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	12%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

INT+FP

all	12%
load	12%
store	12%
mul	12%
add-sub	12%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	12%
other	11%

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each call to the function takes 13.50 cycles. At this rate:

4% of peak load performance is reached (4.74 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
6% of peak store performance is reached (4.15 out of 64.00 bytes stored per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Performance is limited by instruction throughput (loading/decoding program instructions to execution core) (front-end is a bottleneck).

ASM code

In the binary file, the address of the function is: 401bf0

Instruction	Nb FU	ALU0/BRU0	ALU1	ALU2	ALU3	BRU1	AGU0	AGU1	AGU2	FP0	FP1	FP2	FP3	FP4	FP5	Latency	Recip. throughput	Vectorization
PUSH %RBP	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A
MOV $0x401060,%RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.33	N/A
MOV %RSP,%RBP	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.17	N/A
PUSH %RBX	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A
SUB $0x8,%RSP	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
CALL %RAX	2	0.50	0	0	0	0.50	0.33	0.33	0.33	0	0	0	0	0	0	0	2	N/A
MOVSXD %EAX,%RBX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (6.3%)
MOV $0x401030,%RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.33	N/A
CALL %RAX	2	0.50	0	0	0	0.50	0.33	0.33	0.33	0	0	0	0	0	0	0	2	N/A
MOVSXD %EAX,%RCX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (6.3%)
MOV $0x33450000,%EAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
CQTO																		scal (12.5%)
IDIV %RBX	2	2	0	0	0	0	0	0	0	0	0	0	0	0	0	9-19	7-12	scal (12.5%)
CMP %RDX,%RCX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JL 401da0 <main._omp_fn.3+0x1b0>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
IMUL %RAX,%RCX	1	0	1	0	0	0	0	0	0	0	0	0	0	0	0	3	1	scal (12.5%)
ADD %RCX,%RDX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
ADD %RDX,%RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
CMP %RAX,%RDX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JGE 401d8c <main._omp_fn.3+0x19c>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
MOV $0x3349060e0,%RSI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.33	N/A
LEA (%RSI,%RAX,8),%R8	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
LEA (%RSI,%RDX,8),%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
MOV %R8,%R9	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.17	scal (12.5%)
SUB %RDI,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
SUB $0x8,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
SHR $0x3,%R9	1	0	0.50	0.50	0	0	0	0	0	0	0	0	0	0	0	1	0.50	scal (12.5%)
INC %R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
AND $0x7,%R9D	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (6.3%)
JE 401d11 <main._omp_fn.3+0x121>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x1,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cfa <main._omp_fn.3+0x10a>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x2,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401ce8 <main._omp_fn.3+0xf8>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x3,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cd6 <main._omp_fn.3+0xe6>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x4,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cc5 <main._omp_fn.3+0xd5>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x5,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401cb4 <main._omp_fn.3+0xc4>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
CMP $0x6,%R9	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401ca3 <main._omp_fn.3+0xb3>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
VMOVSD (%RDI),%XMM0	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM0,%XMM0,%XMM1	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM1,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM2	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM2,%XMM2,%XMM3	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM3,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM4	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM4,%XMM4,%XMM5	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM5,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM6	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM6,%XMM6,%XMM7	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM7,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM8	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM8,%XMM8,%XMM9	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM9,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM10	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM10,%XMM10,%XMM11	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM11,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
VMOVSD (%RDI),%XMM12	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	scal (12.5%)
ADD $0x8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
VADDSD %XMM12,%XMM12,%XMM13	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	3	0.50	scal (12.5%)
VMOVSD %XMM13,-0x8(%RDI)	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0.50	0.50	1	1	scal (12.5%)
CMP %R8,%RDI	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	scal (12.5%)
JE 401d8c <main._omp_fn.3+0x19c>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A
MOV -0x8(%RBP),%RBX	1	0	0	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	3	0.33	scal (12.5%)
LEAVE	2	0.25	0.25	0.25	0.25	0	0.33	0.33	0.33	0	0	0	0	0	0	1	0.50	N/A
RET	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	1	0.50	N/A
NOPW %CS:(%RAX,%RAX,1)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.09	N/A
NOPL (%RAX)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.09	N/A
INC %RAX	1	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	0	0	0	1	0.25	N/A
XOR %EDX,%EDX	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.25	N/A
JMP 401c2a <main._omp_fn.3+0x3a>	1	0.50	0	0	0	0.50	0	0	0	0	0	0	0	0	0	0	1	N/A
NOPW (%RAX,%RAX,1)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.09	N/A

Name	Coverage (%)	Time (s)
▼main._omp_fn.3–	0.67	0.04
○Loop 4 - stream.c:292-292 - exec	0.67	0.04

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Type of elements and instruction set

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

Arithmetic intensity

General properties

Front-end

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Cycles summary

Vectorization ratios

Vector efficiency ratios

Cycles and memory resources usage

Front-end bottlenecks

ASM code