Linked Questions
10 questions linked to/from Bubble sort slower with -O3 than -O2 with GCC
56
votes
2
answers
26k
views
gcc optimization flag -O3 makes code slower than -O2
I find this topic Why is it faster to process a sorted array than an unsorted array? . And try to run this code. And I find strange behavior. If I compile this code with -O3 optimization flag it takes ...
- 2,132
16
votes
1
answer
5k
views
Why does clang produce inefficient asm with -O0 (for this simple floating point sum)?
I am disassembling this code on llvm clang Apple LLVM version 8.0.0 (clang-800.0.42.1):
int main() {
float a=0.151234;
float b=0.2;
float c=a+b;
printf("%f", c);
}
I compiled with no -...
- 145k
12
votes
2
answers
3k
views
Can modern x86 implementations store-forward from more than one prior store?
In the case that a load overlaps two earlier stores (and the load is not fully contained in the oldest store), can modern Intel or AMD x86 implementations forward from both stores to satisfy the load?
...
- 66.7k
1
vote
2
answers
3k
views
Why bubble sort is not efficient?
I am developing backend project using node.js and going to implement sorting products functionality.
I researched some articles and there were several articles saying bubble sort is not efficient.
...
- 687
10
votes
2
answers
1k
views
What are the costs of failed store-to-load forwarding on x86?
What are the costs of a failed store-to-load forwarding on recent x86 architectures?
In particular, store-to-load forwarding that fails because the load partly overlaps an earlier store, or because ...
- 66.7k
2
votes
3
answers
4k
views
Why Java turns out to be faster than C++ in this simple BubbleSort benchmark example?
I hear from colleagues that C++ is faster than Java and when looking for top performance, especially for finance applications, that's the route to go. But my observations differ a bit. Can anyone ...
- 63
1
vote
1
answer
1k
views
Possible to develop a game using assembly language? [closed]
I am wondering what it takes to develop a game in assembly language. For example, what are the limitations or advantages from using assembly language in game development? Also, are there any programs/...
- 55
-7
votes
3
answers
661
views
For comparison in speed between C and Assembly language using bubble sort, which of it in general is faster? [closed]
I have researched bubble sort speed differences between C and Assembly language, and found that code optimization is one factor.
What other factors are there to consider for bubble sort speed ...
- 17
2
votes
0
answers
832
views
Big penalty of unaligned load and store on x86_64 [duplicate]
I thought unaligned access and write has got cheaper on recent x86_64 CPUs compared to the older ones. However, I recently found out that doing a series of unaligned load and stores can be a huge ...
- 2,372
7
votes
0
answers
319
views
MSVC generating unnecessary complicated instructions
While benchmarking code involving std::optional<double>, I noticed that the code MSVC generates runs at roughly half the speed compared to the one produced by clang or gcc. After spending some ...
- 6,363