https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66005
--- Comment #30 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-11 branch has been updated by Thomas Schwinge <tschwi...@gcc.gnu.org>: https://gcc.gnu.org/g:4506b349cf527834239554a03e43ae45237b315c commit r11-10880-g4506b349cf527834239554a03e43ae45237b315c Author: Thomas Schwinge <tho...@codesourcery.com> Date: Tue Apr 25 23:53:12 2023 +0200 Support parallel testing in libgomp, part II [PR66005] ..., and enable if 'flock' is available for serializing execution testing. Regarding the default of 19 parallel slots, this turned out to be a local minimum for wall time when testing this on: $ uname -srvi Linux 4.2.0-42-generic #49~14.04.1-Ubuntu SMP Wed Jun 29 20:22:11 UTC 2016 x86_64 $ grep '^model name' < /proc/cpuinfo | uniq -c 32 model name : Intel(R) Xeon(R) CPU E5-2640 v3 @ 2.60GHz ... in two configurations: case (a) standard configuration, no offloading configured, case (b) offloading for GCN and nvptx configured but no devices available. For both cases, default plus '-m32' variant. $ \time make check-target-libgomp RUNTESTFLAGS="--target_board=unix\{,-m32\}" Case (a), baseline: 6432.23user 332.38system 47:32.28elapsed 237%CPU (0avgtext+0avgdata 505044maxresident)k 6382.43user 319.21system 47:06.04elapsed 237%CPU (0avgtext+0avgdata 505172maxresident)k This is what people have been complaining about, rightly so, in <https://gcc.gnu.org/PR66005> "libgomp make check time is excessive" and elsewhere. Case (a), parallelized: -j12 GCC_TEST_PARALLEL_SLOTS=10 3088.49user 267.74system 6:43.82elapsed 831%CPU (0avgtext+0avgdata 505188maxresident)k -j15 GCC_TEST_PARALLEL_SLOTS=15 3308.08user 294.79system 5:56.04elapsed 1011%CPU (0avgtext+0avgdata 505360maxresident)k -j17 GCC_TEST_PARALLEL_SLOTS=17 3539.93user 298.99system 5:27.86elapsed 1170%CPU (0avgtext+0avgdata 505112maxresident)k -j18 GCC_TEST_PARALLEL_SLOTS=18 3697.50user 317.18system 5:14.63elapsed 1275%CPU (0avgtext+0avgdata 505360maxresident)k -j19 GCC_TEST_PARALLEL_SLOTS=19 3765.94user 324.27system 5:13.22elapsed 1305%CPU (0avgtext+0avgdata 505128maxresident)k -j20 GCC_TEST_PARALLEL_SLOTS=20 3684.66user 312.32system 5:15.26elapsed 1267%CPU (0avgtext+0avgdata 505100maxresident)k -j23 GCC_TEST_PARALLEL_SLOTS=23 4040.59user 347.10system 5:29.12elapsed 1333%CPU (0avgtext+0avgdata 505200maxresident)k -j26 GCC_TEST_PARALLEL_SLOTS=26 3973.24user 377.96system 5:24.70elapsed 1340%CPU (0avgtext+0avgdata 505160maxresident)k -j32 GCC_TEST_PARALLEL_SLOTS=32 4004.42user 346.10system 5:16.11elapsed 1376%CPU (0avgtext+0avgdata 505160maxresident)k Yay! Case (b), baseline; 2+ h: 7227.58user 700.54system 2:14:33elapsed 98%CPU (0avgtext+0avgdata 994264maxresident)k Case (b), parallelized: -j12 GCC_TEST_PARALLEL_SLOTS=10 7377.46user 777.52system 16:06.63elapsed 843%CPU (0avgtext+0avgdata 994344maxresident)k -j15 GCC_TEST_PARALLEL_SLOTS=15 8019.18user 721.42system 12:13.56elapsed 1191%CPU (0avgtext+0avgdata 994228maxresident)k -j17 GCC_TEST_PARALLEL_SLOTS=17 8530.11user 716.95system 10:45.92elapsed 1431%CPU (0avgtext+0avgdata 994176maxresident)k -j18 GCC_TEST_PARALLEL_SLOTS=18 8776.79user 645.89system 10:27.20elapsed 1502%CPU (0avgtext+0avgdata 994248maxresident)k -j19 GCC_TEST_PARALLEL_SLOTS=19 9332.37user 641.76system 10:15.09elapsed 1621%CPU (0avgtext+0avgdata 994260maxresident)k -j20 GCC_TEST_PARALLEL_SLOTS=20 9609.54user 789.88system 10:26.94elapsed 1658%CPU (0avgtext+0avgdata 994284maxresident)k -j23 GCC_TEST_PARALLEL_SLOTS=23 10362.40user 911.14system 10:44.47elapsed 1749%CPU (0avgtext+0avgdata 994208maxresident)k -j26 GCC_TEST_PARALLEL_SLOTS=26 11159.44user 850.99system 11:09.25elapsed 1794%CPU (0avgtext+0avgdata 994256maxresident)k -j32 GCC_TEST_PARALLEL_SLOTS=32 11453.50user 939.52system 11:00.38elapsed 1876%CPU (0avgtext+0avgdata 994240maxresident)k On my Dell Precision 7530 laptop: $ uname -srvi Linux 5.15.0-71-generic #78-Ubuntu SMP Tue Apr 18 09:00:29 UTC 2023 x86_64 $ grep '^model name' < /proc/cpuinfo | uniq -c 12 model name : Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz $ nvidia-smi -L GPU 0: Quadro P1000 (UUID: GPU-e043973b-b52a-d02b-c066-a8fdbf64e8ea) ... in two configurations: case (c) standard configuration, no offloading configured, case (d) offloading for nvptx configured and device available. For both cases, only default variant, no '-m32'. $ \time make check-target-libgomp Case (c), baseline; roughly half of case (a) (just one variant): 1180.98user 110.80system 19:36.40elapsed 109%CPU (0avgtext+0avgdata 505148maxresident)k 1133.22user 111.08system 19:35.75elapsed 105%CPU (0avgtext+0avgdata 505212maxresident)k Case (c), parallelized: -j12 GCC_TEST_PARALLEL_SLOTS=2 1143.83user 110.76system 10:20.46elapsed 202%CPU (0avgtext+0avgdata 505216maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=6 1737.08user 143.94system 4:59.48elapsed 628%CPU (0avgtext+0avgdata 505200maxresident)k 1730.31user 143.02system 4:58.75elapsed 627%CPU (0avgtext+0avgdata 505152maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=8 2192.63user 169.34system 4:52.96elapsed 806%CPU (0avgtext+0avgdata 505216maxresident)k 2219.04user 167.67system 4:53.19elapsed 814%CPU (0avgtext+0avgdata 505152maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=10 2463.93user 184.98system 4:48.39elapsed 918%CPU (0avgtext+0avgdata 505200maxresident)k 2455.62user 183.68system 4:47.40elapsed 918%CPU (0avgtext+0avgdata 505216maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=12 2591.04user 192.64system 4:44.98elapsed 976%CPU (0avgtext+0avgdata 505216maxresident)k 2581.23user 195.21system 4:47.51elapsed 965%CPU (0avgtext+0avgdata 505212maxresident)k -j20 GCC_TEST_PARALLEL_SLOTS=20 [oversubscribe] 2613.18user 199.51system 4:44.06elapsed 990%CPU (0avgtext+0avgdata 505216maxresident)k Case (d), baseline (compared to case (b): only nvptx offloading compilation, but also nvptx offloading execution); ~1 h: 2841.93user 653.68system 1:02:26elapsed 93%CPU (0avgtext+0avgdata 909792maxresident)k 2842.03user 654.39system 1:02:24elapsed 93%CPU (0avgtext+0avgdata 909880maxresident)k Case (d), parallelized: -j12 GCC_TEST_PARALLEL_SLOTS=2 2856.39user 606.87system 33:58.64elapsed 169%CPU (0avgtext+0avgdata 909948maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=6 3444.90user 666.86system 18:37.57elapsed 367%CPU (0avgtext+0avgdata 909856maxresident)k 3462.13user 667.13system 18:36.87elapsed 369%CPU (0avgtext+0avgdata 909872maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=8 3929.74user 716.22system 18:02.36elapsed 429%CPU (0avgtext+0avgdata 909832maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=10 4152.84user 736.16system 17:43.05elapsed 459%CPU (0avgtext+0avgdata 909872maxresident)k -j12 GCC_TEST_PARALLEL_SLOTS=12 4209.60user 749.00system 17:35.20elapsed 469%CPU (0avgtext+0avgdata 909840maxresident)k -j20 GCC_TEST_PARALLEL_SLOTS=20 [oversubscribe] 4255.54user 756.78system 17:29.06elapsed 477%CPU (0avgtext+0avgdata 909868maxresident)k Worth noting is that with nvptx offloading, there is one execution test case that times out ('libgomp.fortran/reverse-offload-5.f90'). This effectively stalls progress for almost 5 min: quickly other executions test cases queue up on the lock for all parallel slots. That's working as expected; just noting this as it accordingly does skew the wall time numbers. PR testsuite/66005 libgomp/ * configure.ac: Look for 'flock'. * testsuite/Makefile.am (gcc_test_parallel_slots): Enable parallel testing. * testsuite/config/default.exp: Don't 'load_lib "standard.exp"' here... * testsuite/lib/libgomp.exp: ... but here, instead. (libgomp_load): Override for parallel testing. * testsuite/libgomp-site-extra.exp.in (FLOCK): Set. * configure: Regenerate. * Makefile.in: Regenerate. * testsuite/Makefile.in: Regenerate. (cherry picked from commit 6c3b30ef9e0578509bdaf59c13da4a212fe6c2ba)
