A small C++ code for illumination rendering. Looks to be multi-threaded and quickly running.
Topdown profile shows backend stalls as largest issue with a moderate retirement rate.
AMD metrics show this is floating point code with small amount of L2 access. Backend stalls are mostly CPU stalls.
elapsed 45.090
on_cpu 0.654 # 10.47 / 16 cores
utime 471.119
stime 0.870
nvcsw 1678 # 25.47%
nivcsw 4911 # 74.53%
inblock 0 # 0.00/sec
onblock 62944 # 1395.95/sec
cpu-clock 472009776505 # 472.010 seconds
task-clock 472014224464 # 472.014 seconds
page faults 163926 # 347.290/sec
context switches 6635 # 14.057/sec
cpu migrations 212 # 0.449/sec
major page faults 12 # 0.025/sec
minor page faults 163914 # 347.265/sec
alignment faults 0 # 0.000/sec
emulation faults 0 # 0.000/sec
branches 290450354693 # 101.312 branches per 1000 inst
branch misses 6280963989 # 2.16% branch miss
conditional 224571701814 # 78.333 conditional branches per 1000 inst
indirect 8558837143 # 2.985 indirect branches per 1000 inst
cpu-cycles 1882296852708 # 2.61 GHz
instructions 2865046175872 # 1.52 IPC
slots 3766723443972 #
retiring 1031193614822 # 27.4% (41.8%)
-- ucode 740624499 # 0.0%
-- fastpath 1030452990323 # 27.4%
frontend 128086560200 # 3.4% ( 5.2%)
-- latency 89260572702 # 2.4%
-- bandwidth 38825987498 # 1.0%
backend 1182909332439 # 31.4% (47.9%)
-- cpu 1030784053449 # 27.4%
-- memory 152125278990 # 4.0%
speculation 124961204508 # 3.3% ( 5.1%)
-- branch mispredict 122654034594 # 3.3%
-- pipeline restart 2307169914 # 0.1%
smt-contention 1299568541868 # 34.5% ( 0.0%)
cpu-cycles 1879246306828 # 2.61 GHz
instructions 2869706329426 # 1.53 IPC
instructions 954570926607 # 0.574 l2 access per 1000 inst
l2 hit from l1 383137104 # 4.29% l2 miss
l2 miss from l1 12700086 #
l2 hit from l2 pf 154085933 #
l3 hit from l2 pf 5453940 #
l3 miss from l2 pf 5369977 #
instructions 955485420525 # 391.055 float per 1000 inst
float 512 77 # 0.000 AVX-512 per 1000 inst
float 256 586 # 0.000 AVX-256 per 1000 inst
float 128 373647513792 # 391.055 AVX-128 per 1000 inst
float MMX 0 # 0.000 MMX per 1000 inst
float scalar 0 # 0.000 scalar per 1000 inst
instructions 2866802424129 #
opcache 402332512660 # 140.342 opcache per 1000 inst
opcache miss 1292555935 # 0.3% opcache miss rate
l1 dTLB miss 31443107 # 0.011 L1 dTLB per 1000 inst
l2 dTLB miss 5381707 # 0.002 L2 dTLB per 1000 inst
instructions 2866800052557 #
icache 2307657177 # 0.805 icache per 1000 inst
icache miss 286395407 # 12.4% icache miss rate
l1 iTLB miss 8608125 # 0.003 L1 iTLB per 1000 inst
l2 iTLB miss 0 # 0.000 L2 iTLB per 1000 inst
tlb flush 16974 # 0.000 TLB flush per 1000 inst
Intel metrics confirm low L2 access and show higher level of branch misprediction
elapsed 46.525
on_cpu 0.673 # 10.77 / 16 cores
utime 500.506
stime 0.384
nvcsw 1211 # 19.40%
nivcsw 5030 # 80.60%
inblock 4656 # 100.08/sec
onblock 51592 # 1108.91/sec
cpu-clock 500904808159 # 500.905 seconds
task-clock 500907949143 # 500.908 seconds
page faults 99508 # 198.655/sec
context switches 6290 # 12.557/sec
cpu migrations 222 # 0.443/sec
major page faults 58 # 0.116/sec
minor page faults 99450 # 198.539/sec
alignment faults 0 # 0.000/sec
emulation faults 0 # 0.000/sec
branches 289123524356 # 101.078 branches per 1000 inst
branch misses 6697550758 # 2.32% branch miss
conditional 289123534756 # 101.078 conditional branches per 1000 inst
indirect 53838970043 # 18.822 indirect branches per 1000 inst
slots 2855244531524 #
retiring 1627251960026 # 57.0% (57.0%) high
-- ucode 35202779377 # 1.2%
-- fastpath 1592049180649 # 55.8%
frontend 521415453265 # 18.3% (18.3%)
-- latency 452095257232 # 15.8%
-- bandwidth 69320196033 # 2.4%
backend 297810108968 # 10.4% (10.4%) low
-- cpu 214954934707 # 7.5%
-- memory 82855174261 # 2.9%
speculation 409638370395 # 14.3% (14.3%) high
-- branch mispredict 409107060915 # 14.3%
-- pipeline restart 531309480 # 0.0%
smt-contention 0 # 0.0% ( 0.0%)
cpu-cycles 3296409027952 # 2.19 GHz
instructions 5741847939829 # 1.74 IPC
l2 access 306096009 # 0.094 l2 access per 1000 inst
l2 miss 67249322 # 21.97% l2 miss
cpu-cycles 1860051893950 # 16.4% memory latency
load stalls 304362400662 # 16.3% l1 bound
l1 miss 798391811 # 0.0% l2 bound
l2 miss 362458552 # 0.0% l3 bound
l3 miss 166527645 # 0.0% dram bound
store_stalls 143931493 # 0.0% store bound
Process profile shows the smallpt-rendere process is primary process
384 processes
48 smallpt-rendere 7485.92 2.08
68 clinfo 15.87 6.24
38 vulkaninfo 1.15 1.14
4 vulkani:disk$0 0.12 0.12
6 php 0.06 0.06
2 llvmpipe-0 0.06 0.06
2 llvmpipe-1 0.06 0.06
2 llvmpipe-10 0.06 0.06
2 llvmpipe-11 0.06 0.06
2 llvmpipe-12 0.06 0.06
2 llvmpipe-13 0.06 0.06
2 llvmpipe-14 0.06 0.06
2 llvmpipe-15 0.06 0.06
2 llvmpipe-2 0.06 0.06
2 llvmpipe-3 0.06 0.06
2 llvmpipe-4 0.06 0.06
2 llvmpipe-5 0.06 0.06
2 llvmpipe-6 0.06 0.06
2 llvmpipe-7 0.06 0.06
2 llvmpipe-8 0.06 0.06
2 llvmpipe-9 0.06 0.06
6 clang 0.05 0.07
3 rocminfo 0.00 0.03
1 lspci 0.00 0.02
84 sh 0.00 0.00
13 gcc 0.00 0.00
11 gsettings 0.00 0.00
8 stat 0.00 0.00
8 systemd-detect- 0.00 0.00
6 llvm-link 0.00 0.00
5 glxinfo 0.00 0.00
5 phoronix-test-s 0.00 0.00
3 gmain 0.00 0.00
3 smallpt 0.00 0.00
2 cc 0.00 0.00
2 dconf worker 0.00 0.00
2 grep 0.00 0.00
2 lscpu 0.00 0.00
2 setterm 0.00 0.00
2 uname 0.00 0.00
2 which 0.00 0.00
1 date 0.00 0.00
1 dirname 0.00 0.00
1 dmesg 0.00 0.00
1 dmidecode 0.00 0.00
1 ifconfig 0.00 0.00
1 ip 0.00 0.00
1 lsmod 0.00 0.00
1 mktemp 0.00 0.00
1 ps 0.00 0.00
1 qdbus 0.00 0.00
1 readlink 0.00 0.00
1 realpath 0.00 0.00
1 sed 0.00 0.00
1 sort 0.00 0.00
1 stty 0.00 0.00
1 systemctl 0.00 0.00
1 template.sh 0.00 0.00
1 wc 0.00 0.00
0 processes running
47 maximum processes
Process tree shows following pattern for core computation blocks.
230105) smallpt cpu=1 start=5.51 finish=15.35
230106) smallpt-rendere cpu=11 start=5.51 finish=15.35
230107) smallpt-rendere cpu=6 start=5.52 finish=15.35
230108) smallpt-rendere cpu=12 start=5.52 finish=15.35
230109) smallpt-rendere cpu=8 start=5.52 finish=15.35
230110) smallpt-rendere cpu=15 start=5.52 finish=15.35
230111) smallpt-rendere cpu=5 start=5.52 finish=15.35
230112) smallpt-rendere cpu=2 start=5.52 finish=15.35
230113) smallpt-rendere cpu=9 start=5.52 finish=15.35
230114) smallpt-rendere cpu=3 start=5.52 finish=15.35
230115) smallpt-rendere cpu=13 start=5.52 finish=15.35
230116) smallpt-rendere cpu=4 start=5.52 finish=15.35
230117) smallpt-rendere cpu=14 start=5.52 finish=15.35
230118) smallpt-rendere cpu=7 start=5.52 finish=15.35
230119) smallpt-rendere cpu=10 start=5.53 finish=15.35
230120) smallpt-rendere cpu=0 start=5.53 finish=15.35
230121) smallpt-rendere cpu=1 start=5.53 finish=15.35