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https://github.com/martinus/map_benchmark
Comprehensive benchmarks of C++ maps
https://github.com/martinus/map_benchmark
benchmark c-plus-plus hashmaps
Last synced: 3 days ago
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Comprehensive benchmarks of C++ maps
- Host: GitHub
- URL: https://github.com/martinus/map_benchmark
- Owner: martinus
- License: mit
- Created: 2018-06-03T17:49:54.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2023-04-14T07:42:57.000Z (almost 2 years ago)
- Last Synced: 2025-01-15T09:56:17.633Z (11 days ago)
- Topics: benchmark, c-plus-plus, hashmaps
- Language: C++
- Size: 19.7 MB
- Stars: 302
- Watchers: 13
- Forks: 29
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# map_benchmark
Comprehensive benchmarks of C++ maps
# Results
[Please see here.](https://martin.ankerl.com/2019/04/01/hashmap-benchmarks-01-overview/)
# building
1. Install dependencies for folly::F14, see https://github.com/facebook/folly/#ubuntu-1604-lts
1. Install `ninja` and `cmake`
```
git clone --recurse-submodules https://github.com/martinus/map_benchmark.git
./map_benchmark/tools/build.sh
```
# Updating Submodules
```sh
git submodule update --force --remote
```
# Sourcecode Layout
The implementation if the benchmark is open source, get it here: [martinus/map_benchmark](https://github.com/martinus/map_benchmark). It is split in several parts:
1. `external`: all map implementations available through github are added as git submodules here.
1. `src/hashes`: One directory for each hashing algorithm, each directory contains a `Hash.h` which basically contains a `using` instruction for the hash, e.g. like this:
```cpp
template
using Hash = robin_hood::hash;
```
1. `src/maps`: One directory for each unordered map implementation, each directory contains a `Map.h` which basically contains a `using` instruction for the map. It includes `Hash.h`. E.g. like this:
```cpp
#include "Hash.h"
template
using Map = robin_hood::unordered_flat_map>;
```
# Add a new Hashmap
1. In `external`, add a submodule:
```
cd external
git submodule add -b master https://github.com/rigtorp/HashMap.git rigtorp__HashMap
```
2. Create a directory in `src/map/` with a file `Hash.h`. See the others for example.
# Maps I couldn't add
* [QHash](https://github.com/qt/qtbase): It's interface is too different to be easily includeable. e.g. `iterator->first` and `iterator->second` do not exist.
* [rigtorp::HashMap](https://github.com/rigtorp/HashMap): Doesn't have a default constructor
# Reliable Benchmarks
1. Run `lscpu --extended` to find out if you have hyperthreadding. E.g. for me it shows
```
$ lscpu --extended
CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE MAXMHZ MINMHZ
0 0 0 0 0:0:0:0 yes 4600,0000 800,0000
1 0 0 1 1:1:1:0 yes 4600,0000 800,0000
2 0 0 2 2:2:2:0 yes 4600,0000 800,0000
3 0 0 3 3:3:3:0 yes 4600,0000 800,0000
4 0 0 4 4:4:4:0 yes 4600,0000 800,0000
5 0 0 5 5:5:5:0 yes 4600,0000 800,0000
6 0 0 0 0:0:0:0 yes 4600,0000 800,0000
7 0 0 1 1:1:1:0 yes 4600,0000 800,0000
8 0 0 2 2:2:2:0 yes 4600,0000 800,0000
9 0 0 3 3:3:3:0 yes 4600,0000 800,0000
10 0 0 4 4:4:4:0 yes 4600,0000 800,0000
11 0 0 5 5:5:5:0 yes 4600,0000 800,0000
```
1. Isolate a CPU with it's hyperthreading companion. I'm isolating CPU 5 and 11.
1. Edit `/etc/default/grub` and change GRUB_CMDLINE_LINUX_DEFAULT so it looks like this:
```
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash isolcpus=5,11 rcu_nocbs=5,11"
```
1. Run `sudo update-grub`
1. reboot
1. Edit `bench.rb` so the `taskset -c ...` prefix is correct.
1. Install Python module `perf`, see https://perf.readthedocs.io/en/latest/
1. Run `sudo python3 -m perf system tune`
1. Start the benchmarks: ```../tools/bench.rb |tee ../data/all_new.txt```
Sources:
* https://wiki.ubuntuusers.de/GRUB_2/Konfiguration/
* https://perf.readthedocs.io/en/latest/system.html