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multithreading_assembly_perf_test - 2025-05-20 10:57:29 - MAQAO 2.21.4

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Stylizer  

[ 0 / 4 ] Application profile is too short (8.58 s)

If the overall application profiling time is less than 10 seconds, many of the measurements at function or loop level will very likely be under the measurement quality threshold (0,1 seconds). Rerun to increase runtime duration: for example use a larger dataset or include a repetition loop.

[ 3 / 3 ] Optimization level option is correctly used

[ 2.97 / 3 ] Most of time spent in analyzed modules comes from functions compiled with -g and -fno-omit-frame-pointer

-g option gives access to debugging informations, such are source locations. -fno-omit-frame-pointer improve the accuracy of callchains found during the application profiling.

[ 2 / 3 ] Security settings from the host restrict profiling. Some metrics will be missing or incomplete.

Current value for kernel.perf_event_paranoid is 2. If possible, set it to 1 or check with your system administrator which flag can be used to achieve this.

[ 2.97 / 3 ] Architecture specific option -march=znver is used

[ 2 / 2 ] Application is correctly profiled ("Others" category represents 1.51 % of the execution time)

To have a representative profiling, it is advised that the category "Others" represents less than 20% of the execution time in order to analyze as much as possible of the user code

[ 1 / 1 ] Lstopo present. The Topology lstopo report will be generated.

[ 0 / 0 ] Fastmath not used

Consider to add ffast-math to compilation flags (or replace -O3 with -Ofast) to unlock potential extra speedup by relaxing floating-point computation consistency. Warning: floating-point accuracy may be reduced and the compliance to IEEE/ISO rules/specifications for math functions will be relaxed, typically 'errno' will no longer be set after calling some math functions.

Strategizer  

[ 0 / 4 ] Too little time of the experiment time spent in analyzed loops (4.34%)

If the time spent in analyzed loops is less than 30%, standard loop optimizations will have a limited impact on application performances.

[ 0 / 4 ] CPU activity is below 90% (26.90%)

CPU cores are idle more than 10% of time. Threads supposed to run on these cores are probably IO/sync waiting. Some hints: use faster filesystems to read/write data, improve parallel load balancing and/or scheduling.

[ 0 / 4 ] A significant amount of threads are idle (86.89%)

On average, more than 10% of observed threads are idle. Such threads are probably IO/sync waiting. Some hints: use faster filesystems to read/write data, improve parallel load balancing and/or scheduling.

[ 0 / 4 ] Affinity stability is lower than 90% (26.95%)

Threads are often migrating to other CPU cores/threads. For OpenMP, typically set (OMP_PLACES=cores OMP_PROC_BIND=close) or (OMP_PLACES=threads OMP_PROC_BIND=spread). With OpenMPI + OpenMP, use --bind-to core --map-by node:PE=$OMP_NUM_THREADS --report-bindings. With IntelMPI + OpenMP, set I_MPI_PIN_DOMAIN=omp:compact or I_MPI_PIN_DOMAIN=omp:scatter and use -print-rank-map.

[ 0 / 4 ] Loop profile is flat

No hotspot found in the application (greatest loop coverage is 1.67%), and the twenty hottest loops cumulated coverage is lower than 20% of the application profiled time (4.34%)

[ 0 / 4 ] Too little time of the experiment time spent in analyzed innermost loops (2.61%)

If the time spent in analyzed innermost loops is less than 15%, standard innermost loop optimizations such as vectorisation will have a limited impact on application performances.

[ 3 / 3 ] Cumulative Outermost/In between loops coverage (1.73%) lower than cumulative innermost loop coverage (2.61%)

Having cumulative Outermost/In between loops coverage greater than cumulative innermost loop coverage will make loop optimization more complex

[ 3 / 3 ] Less than 10% (0.00%) is spend in BLAS1 operations

It could be more efficient to inline by hand BLAS1 operations

[ 2 / 2 ] Less than 10% (0.08%) is spend in BLAS2 operations

BLAS2 calls usually could make a poor cache usage and could benefit from inlining.

[ 2 / 2 ] Less than 10% (0.00%) is spend in Libm/SVML (special functions)

Optimizer

Loop IDAnalysisPenalty Score
Loop 292 - multithreading_assembly_perf_testExecution Time: 1 % - Vectorization Ratio: 0.00 % - Vector Length Use: 6.25 %
Loop 290 - multithreading_assembly_perf_test+Execution Time: 1 % - Vectorization Ratio: 0.00 % - Vector Length Use: 0.00 %
Control Flow Issues+5
[SA] Several paths (3 paths) - Simplify control structure or force the compiler to use masked instructions. There are 3 issues ( = paths) costing 1 point each.3
[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
Vectorization Roadblocks+5
[SA] Several paths (3 paths) - Simplify control structure or force the compiler to use masked instructions. There are 3 issues ( = paths) costing 1 point each.3
[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
Loop 5783 - libfinite_elements.so+Execution Time: 0 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 %
Data Access Issues+4
[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 2 issues ( = data accesses) costing 2 point each.4
Vectorization Roadblocks+4
[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 2 issues ( = data accesses) costing 2 point each.4
Loop 5808 - libfinite_elements.so+Execution Time: 0 % - Vectorization Ratio: 29.60 % - Vector Length Use: 22.31 %
Control Flow Issues+1
[SA] Presence of calls - Inline either by compiler or by hand and use SVML for libm calls. There are 1 issues (= calls) costing 1 point each.1
Data Access Issues+92
[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 2 issues ( = data accesses) costing 2 point each.4
[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE, BROADCAST, Other_packing) - Simplify data access and try to get stride 1 access. There are 86 issues (= instructions) costing 1 point each.86
[SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points.2
Vectorization Roadblocks+5
[SA] Presence of calls - Inline either by compiler or by hand and use SVML for libm calls. There are 1 issues (= calls) costing 1 point each.1
[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 2 issues ( = data accesses) costing 2 point each.4
Inefficient Vectorization+88
[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE, BROADCAST, Other_packing) - Simplify data access and try to get stride 1 access. There are 86 issues (= instructions) costing 1 point each.86
[SA] Inefficient vectorization: use of masked instructions - Simplify control structure. The issue costs 2 points.2
Loop 5809 - libfinite_elements.so+Execution Time: 0 % - Vectorization Ratio: 0.00 % - Vector Length Use: 0.00 %
Control Flow Issues+36
[SA] Too many paths (32 paths) - Simplify control structure. There are 32 issues ( = paths) costing 1 point each with a malus of 4 points.36
Vectorization Roadblocks+36
[SA] Too many paths (32 paths) - Simplify control structure. There are 32 issues ( = paths) costing 1 point each with a malus of 4 points.36
Loop 291 - multithreading_assembly_perf_test+Execution Time: 0 % - Vectorization Ratio: 0.00 % - Vector Length Use: 0.00 %
Control Flow Issues+2
[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
Vectorization Roadblocks+2
[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
Loop 289 - multithreading_assembly_perf_test+Execution Time: 0 % - Vectorization Ratio: 0.00 % - Vector Length Use: 10.70 %
Loop Computation Issues+2
[SA] Presence of a large number of scalar integer instructions - Simplify loop structure, perform loop splitting or perform unroll and jam. This issue costs 2 points.2
Control Flow Issues+31
[SA] Too many paths (25 paths) - Simplify control structure. There are 25 issues ( = paths) costing 1 point each with a malus of 4 points.29
[SA] Non innermost loop (Outermost) - Collapse loop with innermost ones. This issue costs 2 points.2
Data Access Issues+2
[SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points.2
Vectorization Roadblocks+31
[SA] Too many paths (25 paths) - Simplify control structure. There are 25 issues ( = paths) costing 1 point each with a malus of 4 points.29
[SA] Non innermost loop (Outermost) - Collapse loop with innermost ones. This issue costs 2 points.2
Loop 293 - multithreading_assembly_perf_test+Execution Time: 0 % - Vectorization Ratio: 0.00 % - Vector Length Use: 6.25 %
Control Flow Issues+21
[SA] Too many paths (17 paths) - Simplify control structure. There are 17 issues ( = paths) costing 1 point each with a malus of 4 points.21
Vectorization Roadblocks+21
[SA] Too many paths (17 paths) - Simplify control structure. There are 17 issues ( = paths) costing 1 point each with a malus of 4 points.21
Loop 4828 - libfinite_elements.so+Execution Time: 0 % - Vectorization Ratio: 44.64 % - Vector Length Use: 26.71 %
Loop Computation Issues+5
[SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points.5
Control Flow Issues+6
[SA] Presence of calls - Inline either by compiler or by hand and use SVML for libm calls. There are 1 issues (= calls) costing 1 point each.1
[SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points.5
Data Access Issues+57
[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE) - Simplify data access and try to get stride 1 access. There are 55 issues (= instructions) costing 1 point each.55
[SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points.2
Vectorization Roadblocks+1
[SA] Presence of calls - Inline either by compiler or by hand and use SVML for libm calls. There are 1 issues (= calls) costing 1 point each.1
Inefficient Vectorization+55
[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE) - Simplify data access and try to get stride 1 access. There are 55 issues (= instructions) costing 1 point each.55
Loop 287 - multithreading_assembly_perf_test+Execution Time: 0 % - Vectorization Ratio: 0.00 % - Vector Length Use: 12.50 %
Loop Computation Issues+4
[SA] Less than 10% of the FP ADD/SUB/MUL arithmetic operations are performed using FMA - Reorganize arithmetic expressions to exhibit potential for FMA. This issue costs 4 points.4
Data Access Issues+16
[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 8 issues ( = data accesses) costing 2 point each.16
Vectorization Roadblocks+16
[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 8 issues ( = data accesses) costing 2 point each.16
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