3 ms·

I can't reproduce. When I run The code is here: https://github.com/gsauthof/osjitter/blob/master/bench_syscalls.cc https://github.com/gsauthof/osjitter/blob/mas

by ori_b 1y ago

I can't reproduce. When I run The code is here: https://github.com/gsauthof/osjitter/blob/master/bench_syscalls.cc https://github.com/gsauthof/osjitter/blob/master/bench_sysca..., here are the numbers on the computers I have: AMD Ryzen 7 9700X Desktop: ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 38.6 ns 38.5 ns 18160546 bench_getpid 39.9 ns 39.9 ns 17703749 bench_close 45.2 ns 45.1 ns 15711379 bench_syscall 42.2 ns 42.1 ns 16638675 bench_sched_yield 81.7 ns 81.6 ns 8623522 bench_clock_gettime 15.9 ns 15.9 ns 44010857 bench_clock_gettime_tai 15.9 ns 15.9 ns 43997256 bench_clock_gettime_monotonic 15.9 ns 15.9 ns 44012908 bench_clock_gettime_monotonic_raw 15.9 ns 15.9 ns 43982277 bench_nanosleep0 49961 ns 370 ns 100000 bench_nanosleep0_slack1 10839 ns 351 ns 1000000 bench_nanosleep1_slack1 10878 ns 358 ns 1000000 bench_pthread_cond_signal 1.37 ns 1.37 ns 503715097 bench_assign 0.563 ns 0.562 ns 1000000000 bench_sqrt 1.63 ns 1.63 ns 430096636 bench_sqrtrec 5.33 ns 5.33 ns 132574542 bench_nothing 0.394 ns 0.394 ns 1000000000 12th Gen Intel(R) Core(TM) i5-12600H ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 70.0 ns 70.0 ns 9985369 bench_getpid 71.6 ns 71.6 ns 9763016 bench_close 76.7 ns 76.7 ns 9131090 bench_syscall 66.8 ns 66.8 ns 10533946 bench_sched_yield 160 ns 160 ns 4377987 bench_clock_gettime 12.2 ns 12.2 ns 57432496 bench_clock_gettime_tai 12.1 ns 12.1 ns 57826299 bench_clock_gettime_monotonic 12.2 ns 12.2 ns 57736141 bench_clock_gettime_monotonic_raw 12.3 ns 12.3 ns 57070425 bench_nanosleep0 63154 ns 11834 ns 55756 bench_nanosleep0_slack1 2933 ns 1700 ns 348675 bench_nanosleep1_slack1 2654 ns 1479 ns 467420 bench_pthread_cond_signal 1.39 ns 1.39 ns 483995101 bench_assign 0.868 ns 0.868 ns 821103909 bench_sqrt 1.69 ns 1.69 ns 422094139 bench_sqrtrec 4.06 ns 4.06 ns 174511095 bench_nothing 0.750 ns 0.750 ns 941204159 AMD Ryzen 5 PRO 7545U Laptop: ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 106 ns 106 ns 6581746 bench_getpid 111 ns 111 ns 6271878 bench_close 116 ns 116 ns 5944154 bench_syscall 85.9 ns 85.9 ns 7317584 bench_sched_yield 315 ns 315 ns 2249333 bench_clock_gettime 17.6 ns 17.6 ns 39935693 bench_clock_gettime_tai 17.6 ns 17.6 ns 39920957 bench_clock_gettime_monotonic 17.5 ns 17.5 ns 39962966 bench_clock_gettime_monotonic_raw 17.5 ns 17.5 ns 39561163 bench_nanosleep0 52720 ns 3058 ns 100000 bench_nanosleep0_slack1 13815 ns 2969 ns 244790 bench_nanosleep1_slack1 13710 ns 2722 ns 254666 bench_pthread_cond_signal 2.66 ns 2.66 ns 264735233 bench_assign 0.930 ns 0.930 ns 813279743 bench_sqrt 2.43 ns 2.43 ns 286953468 bench_sqrtrec 5.67 ns 5.67 ns 123889652 bench_nothing 0.812 ns 0.812 ns 860562208 So, I've tested multiple times in multiple ways, and the results don't seem to match.

menaerus 1y ago
Interesting because on my machine I can reproduce the results. It's a pretty hefty 5.3GHz and recentish (Raptor Lake) Intel i7-13850HX CPU: ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 384 ns 384 ns 1822307 bench_getpid 382 ns 382 ns 1835289 bench_close 390 ns 390 ns 1796493 bench_syscall 374 ns 374 ns 1874165 bench_sched_yield 611 ns 611 ns 1143456 bench_clock_gettime 44.1 ns 44.1 ns 15872740 bench_clock_gettime_tai 44.1 ns 44.1 ns 15879915 bench_clock_gettime_monotonic 44.1 ns 44.1 ns 15887383 bench_clock_gettime_monotonic_raw 44.4 ns 44.4 ns 15755225 bench_nanosleep0 55617 ns 4647 ns 100000 bench_nanosleep0_slack1 7144 ns 4362 ns 160448 bench_nanosleep1_slack1 7159 ns 4369 ns 160645 bench_pthread_cond_signal 7.38 ns 7.38 ns 94670062 bench_assign 0.523 ns 0.523 ns 1000000000 bench_sqrt 8.04 ns 8.04 ns 86998912 bench_sqrtrec 11.4 ns 11.4 ns 61428535 bench_nothing 0.000 ns 0.000 ns 1000000000 EDIT: also reproducible on my skylake-x (Gold 6152) machine With turbo-boost @3.7Ghz enabled: ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 619 ns 616 ns 1153007 bench_getpid 632 ns 627 ns 1150829 bench_close 629 ns 626 ns 1110226 bench_syscall 617 ns 613 ns 1160239 bench_sched_yield 974 ns 969 ns 702773 bench_clock_gettime 17.9 ns 17.8 ns 39368735 bench_clock_gettime_tai 17.8 ns 17.7 ns 39109544 bench_clock_gettime_monotonic 17.9 ns 17.8 ns 39591364 bench_clock_gettime_monotonic_raw 19.0 ns 18.8 ns 38902038 bench_nanosleep0 63993 ns 4381 ns 100000 bench_nanosleep0_slack1 7445 ns 2115 ns 328474 bench_nanosleep1_slack1 7346 ns 2111 ns 334833 bench_pthread_cond_signal 2.13 ns 2.12 ns 327903411 bench_assign 0.167 ns 0.166 ns 1000000000 bench_sqrt 1.87 ns 1.85 ns 374885774 bench_sqrtrec 0.000 ns 0.000 ns 1000000000 bench_nothing 0.000 ns 0.000 ns 1000000000 With turbo-boost disabled (@2.1GHz base frequency): ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 1019 ns 1012 ns 688965 bench_getpid 1057 ns 1048 ns 688020 bench_close 1039 ns 1029 ns 684537 bench_syscall 1010 ns 1003 ns 696919 bench_sched_yield 1653 ns 1642 ns 434212 bench_clock_gettime 30.7 ns 30.4 ns 22999055 bench_clock_gettime_tai 30.5 ns 30.2 ns 23716873 bench_clock_gettime_monotonic 29.8 ns 29.6 ns 23643198 bench_clock_gettime_monotonic_raw 30.5 ns 30.3 ns 23277717 bench_nanosleep0 65256 ns 5114 ns 100000 bench_nanosleep0_slack1 11649 ns 3402 ns 197983 bench_nanosleep1_slack1 11572 ns 3528 ns 209371 bench_pthread_cond_signal 3.62 ns 3.60 ns 195696177 bench_assign 0.255 ns 0.253 ns 1000000000 bench_sqrt 3.13 ns 3.10 ns 225561559 bench_sqrtrec 0.000 ns 0.000 ns 1000000000 bench_nothing 0.000 ns 0.000 ns 1000000000 I wonder why your results are so much different. Mine almost linearly scale with the core frequency.

by ori_b 1y ago

menaerus 1y ago

Interesting because on my machine I can reproduce the results. It's a pretty hefty 5.3GHz and recentish (Raptor Lake) Intel i7-13850HX CPU: ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 384 ns 384 ns 1822307 bench_getpid 382 ns 382 ns 1835289 bench_close 390 ns 390 ns 1796493 bench_syscall 374 ns 374 ns 1874165 bench_sched_yield 611 ns 611 ns 1143456 bench_clock_gettime 44.1 ns 44.1 ns 15872740 bench_clock_gettime_tai 44.1 ns 44.1 ns 15879915 bench_clock_gettime_monotonic 44.1 ns 44.1 ns 15887383 bench_clock_gettime_monotonic_raw 44.4 ns 44.4 ns 15755225 bench_nanosleep0 55617 ns 4647 ns 100000 bench_nanosleep0_slack1 7144 ns 4362 ns 160448 bench_nanosleep1_slack1 7159 ns 4369 ns 160645 bench_pthread_cond_signal 7.38 ns 7.38 ns 94670062 bench_assign 0.523 ns 0.523 ns 1000000000 bench_sqrt 8.04 ns 8.04 ns 86998912 bench_sqrtrec 11.4 ns 11.4 ns 61428535 bench_nothing 0.000 ns 0.000 ns 1000000000 EDIT: also reproducible on my skylake-x (Gold 6152) machine With turbo-boost @3.7Ghz enabled: ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 619 ns 616 ns 1153007 bench_getpid 632 ns 627 ns 1150829 bench_close 629 ns 626 ns 1110226 bench_syscall 617 ns 613 ns 1160239 bench_sched_yield 974 ns 969 ns 702773 bench_clock_gettime 17.9 ns 17.8 ns 39368735 bench_clock_gettime_tai 17.8 ns 17.7 ns 39109544 bench_clock_gettime_monotonic 17.9 ns 17.8 ns 39591364 bench_clock_gettime_monotonic_raw 19.0 ns 18.8 ns 38902038 bench_nanosleep0 63993 ns 4381 ns 100000 bench_nanosleep0_slack1 7445 ns 2115 ns 328474 bench_nanosleep1_slack1 7346 ns 2111 ns 334833 bench_pthread_cond_signal 2.13 ns 2.12 ns 327903411 bench_assign 0.167 ns 0.166 ns 1000000000 bench_sqrt 1.87 ns 1.85 ns 374885774 bench_sqrtrec 0.000 ns 0.000 ns 1000000000 bench_nothing 0.000 ns 0.000 ns 1000000000 With turbo-boost disabled (@2.1GHz base frequency): ---------------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------------- bench_getuid 1019 ns 1012 ns 688965 bench_getpid 1057 ns 1048 ns 688020 bench_close 1039 ns 1029 ns 684537 bench_syscall 1010 ns 1003 ns 696919 bench_sched_yield 1653 ns 1642 ns 434212 bench_clock_gettime 30.7 ns 30.4 ns 22999055 bench_clock_gettime_tai 30.5 ns 30.2 ns 23716873 bench_clock_gettime_monotonic 29.8 ns 29.6 ns 23643198 bench_clock_gettime_monotonic_raw 30.5 ns 30.3 ns 23277717 bench_nanosleep0 65256 ns 5114 ns 100000 bench_nanosleep0_slack1 11649 ns 3402 ns 197983 bench_nanosleep1_slack1 11572 ns 3528 ns 209371 bench_pthread_cond_signal 3.62 ns 3.60 ns 195696177 bench_assign 0.255 ns 0.253 ns 1000000000 bench_sqrt 3.13 ns 3.10 ns 225561559 bench_sqrtrec 0.000 ns 0.000 ns 1000000000 bench_nothing 0.000 ns 0.000 ns 1000000000 I wonder why your results are so much different. Mine almost linearly scale with the core frequency.