https://github.com/puzzlef/vector-sum-openmp

Comparing performance of sequential vs OpenMP-based vector element sum.
https://github.com/puzzlef/vector-sum-openmp

element experiment multi-threaded openmp sequential single-threaded sum vector

Last synced: 5 months ago
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Comparing performance of sequential vs OpenMP-based vector element sum.

• Host: GitHub
• URL: https://github.com/puzzlef/vector-sum-openmp
• Owner: puzzlef
• License: mit
• Created: 2021-05-11T16:41:29.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2023-02-11T11:25:14.000Z (almost 3 years ago)
• Last Synced: 2025-04-06T12:43:53.041Z (9 months ago)
• Topics: element, experiment, multi-threaded, openmp, sequential, single-threaded, sum, vector
• Language: C++
• Homepage:
• Size: 81.1 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
Comparing performance of *sequential* vs *OpenMP-based* **vector element sum**.




### Adjusting OpenMP schedule

In this experiment ([adjust-schedule]), we sum together all values of a

floating-point vector `x`, with number of **elements** from `1E+6` to `1E+9`

using OpenMP. We attempt each element with various **OpenMP schedule**

**configs**, running each config 5 times to get a good time measure. Sum here

represents any `reduce()` operation that processes several values to a single

value. Our results indicate a **schedule-kind** of `auto`/`guided` to be suitable.

[adjust-schedule]: https://github.com/puzzlef/vector-sum-openmp/tree/adjust-schedule




### Comparison with Sequential approach

In this experiment ([compare-sequential], [main]), we compare the performance

between finding `Σx` using a single thread (**sequential**) or **OpenMP**. While

it might seem that **OpenMP** method would be a clear winner, our results

indicate it is dependent upon the workload, i.e., from `10⁵` elements, OpenMP

approach performs *better* than sequential. All outputs are saved in [gist].

Some [charts] are also included below, generated from [sheets].

[compare-sequential]: https://github.com/puzzlef/vector-sum-openmp/tree/compare-sequential

[main]: https://github.com/puzzlef/vector-sum-openmp




[![](https://i.imgur.com/gdJQIVJ.png)][sheetp]

[![](https://i.imgur.com/4VKbI6Q.png)][sheetp]







## References

- [Parallel for loop in openmp](https://stackoverflow.com/a/11773714/1413259)

- [What's the difference between “static” and “dynamic” schedule in OpenMP?](https://stackoverflow.com/a/10852852/1413259)

- [Git pulling a branch from another repository?](https://stackoverflow.com/a/46289324/1413259)







[![](https://i.imgur.com/Va4qBPD.jpg)](https://www.youtube.com/watch?v=0XTLuFpuAtE)

![](https://ga-beacon.deno.dev/G-KD28SG54JQ:hbAybl6nQFOtmVxW4if3xw/github.com/puzzlef/vector-sum-openmp)

[gist]: https://gist.github.com/wolfram77/9b90248012dda38727d57e12786ff40c

[charts]: https://photos.app.goo.gl/ruBBeXTz6vEATFQc6

[sheets]: https://docs.google.com/spreadsheets/d/1ZBp9TFxisTn_8_7_X_2HSPt_SbmP16gUW6_fiMtr8rc/edit?usp=sharing

[sheetp]: https://docs.google.com/spreadsheets/d/e/2PACX-1vTPFQlVfelJvgStWlpUnmAWcTZZXpYbL4APW0nc0djGLIGJdWABXx6S2QLkrxHbct_jnXJ51JlB7cv7/pubhtml