| // hash_bench2.cc (compute std::hash once per key) | |
| // based on https://github.com/greg7mdp/parallel-hashmap/blob/master/examples/hash_bench.cc | |
| // | |
| // clang++ -o hash_bench2 -std=c++20 -Wall -O3 hash_bench2.cc -I./parallel-hashmap | |
| #include <iostream> | |
| #include <string> | |
| #include <array> | |
| #include <cstdint> | |
| #include <limits> |
I came across Parallel Hashmap for C++. It provides a parallel demonstration to count the number of occurrences of each word in a large text file using multiple threads. This gist includes complimentary chunking variants for comparison. Results were captured on Clear Linux and Fedora 38.
# Download Jane Austin "Pride and Prejudice".
| // Grep PCRE2 C++ OpenMP demonstration for website: | |
| // https://cpufun.substack.com/p/processing-a-file-with-openmp | |
| // | |
| // By Mario Roy - May 19, 2023 | |
| // License: GNU General Public License. | |
| // See http://www.gnu.org/licenses/ for license information. | |
| // SPDX-License-Identifier: GPL-3.0-or-later | |
| // Based on rtoa-pgatram-allinone2b.cpp: | |
| // https://perlmonks.org/?node_id=11152225 | |
| // |
| 29a30 | |
| > CONFIG_UAPI_HEADER_TEST=y | |
| 6187d6187 | |
| < # CONFIG_VIDEO_PCI_SKELETON is not set | |
| 10496c10496 | |
| < CONFIG_FS_VERITY_BUILTIN_SIGNATURES=y | |
| --- | |
| > # CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not set | |
| 10849c10849 | |
| < CONFIG_LSM_MMAP_MIN_ADDR=0 |
| ################################################################# | |
| # Install minimum dependencies. | |
| ################################################################# | |
| # On "Fedora"-based systems, install minimum dependencies. | |
| # sudo dnf install binutils libgcc glibc-devel libstdc++ patchelf wget | |
| # On "Clear Linux" 40690+, install minimum dependencies. | |
| # sudo swupd bundle-add c-basic patchelf wget | |
| # Fetch gcc-12 packages from Debian: |
| #!/usr/bin/env perl | |
| =pod | |
| =head1 NAME | |
| mcesort - Sort files or standard input in parallel | |
| =head1 SYNOPSIS |
| #!/usr/bin/env perl | |
| # cd $HOME/git/mce-perl or mce-shared | |
| # ../update_version.pl README.md `find lib -name "*.p*"` | |
| use strict; | |
| use warnings; | |
| use File::Inplace; | |
| my $old = '1.874'; |
| Terminal 1: mce-sort2 --maxworkers=40 --bm --check --no-output -e tr-radix random.txt | |
| Terminal 2: [rootuser] cyclictest --smp -p98 -m -D 50 -q | |
| Linux clr-linux 5.10.19-1032.native #1 SMP | |
| mce-sort2 : 26.0 seconds (memory bound, sort 32GiB file under /dev/shm) | |
| # /dev/cpu_dma_latency set to 0us | |
| T: 0 ( 1889) P:98 I:1000 C: 49989 Min: 1 Act: 4 Avg: 7 Max: 7626 | |
| T: 1 ( 1890) P:98 I:1500 C: 33329 Min: 1 Act: 4 Avg: 9 Max: 4429 |
| Terminal 1: numactl -C 0-31 time hackbench -T -f 4 -g 8 -l 3000000 # 64 tasks | |
| Terminal 2: numactl -C 32-63 time hackbench -T -f 4 -g 8 -l 3000000 # 64 tasks | |
| Terminal 3: [rootuser] cyclictest --smp -p98 -m -D 120 -q | |
| Terminal 4: [rootuser] sync; echo 3 > /proc/sys/vm/drop_caches; time ls -R /usr | |
| Linux clr-linux 5.10.19-1032.native #1 SMP | |
| echo 10000000 >/proc/sys/kernel/sched_min_granularity_ns | |
| echo 5000000 >/proc/sys/kernel/sched_migration_cost_ns |
| Terminal 1: numactl -C 0-31 time hackbench -T -f 4 -g 8 -l 3000000 # 64 tasks | |
| Terminal 2: numactl -C 32-63 time hackbench -T -f 4 -g 8 -l 3000000 # 64 tasks | |
| Terminal 3: [rootuser] cyclictest --smp -p98 -m -D 120 -q | |
| Terminal 4: [rootuser] sync; echo 3 > /proc/sys/vm/drop_caches; time ls -R /usr | |
| Linux clr-linux 5.10.19-1032.native #1 SMP | |
| hackbench 1 : 54 seconds | |
| hackbench 2 : 53 seconds | |
| ls -R /usr : 8.5 seconds avg (repeated sync/echo/ls 4 times) |