THthrowaway71271·Sep 1, 2023Submission
Hardware effects – effects that can degrade app performance in surprising ways
1 points · Open discussionKobzol
hardware-effects
C++2018–2023
Kobzol / hardware-effects
hardware-effects
Demonstration of various hardware effects.
4Distinct people
4Mentions
0Explicit recommenders
3KGitHub stars
What to know before exploring
What it is
Demonstration of various hardware effects.
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
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This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year4 dated mentions
Observed mentions: 2018-11-22 16:32:15 UTC to 2023-09-01 16:22:39 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 2 | 1 | 1 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 1 | 1 | 0 |
What Hacker News says
4 sourcesDo you have some more detaile about your app?
I use perf, sysprof, trace32, visual studio profiler for profiling, but this highly depends on your environment.
These assorted links might be interesting to you:
- https://github.com/Kobzol/hardware-effects
- https://www.youtube.com/watch?v=FJJTYQYB1JQ
- https://godbolt.org/
- http://igoro.com/archive/gallery-of-processor-cache-effects/
In Ask HN: What do you recommend for optimization and profiling?The best resource in my opinion is still "What every programmer should know about memory." It is now over ten years old but still the most comprehesive and comprehensible post I know about that topic.
https://lwn.net/Articles/250967/
AFAIK there have been no major breakthroughts since that time in memory technology (Transactional memory could be one). While modern processors may be build a bit different (e.g. added shared L3 chache) you will have no problem understanding them.
There is also this github :
https://github.com/Kobzol/hardware-effects
for programs which should show such effects. (I haven't used them yet but they may be interesting for you to play with.)
IT Hare has published a nice article about those costs including rules of thumb costs.
http://ithare.com/infographics-operation-costs-in-cpu-clock-...
Then there are the Agner
Read the rest
tables. Giving you latencies and reciprocal throughput for your instructions.
https://www.agner.org/optimize/instruction_tables.pdf
If you are through these you have to read the intel and AMD optimization guides. (ARM may or may not have something similar.)
The paper by Kazushige Goto ("Anatomy of a High Performance Matrix Multiplication") is an example of Cache and TLB considerations in a non-trivial example.
http://www.cs.utexas.edu/users/pingali/CS378/2008sp/papers/g...
Demonstration of various hardware effects
1 points · Open discussion