रञ्जित (Ranjit Mathew)Sep 29

“Lock-free” and “branch-less” #programming are fascinating topics:

“The Weird Concept Of ‘Branchless Programming’”, ‘Sanix’ (https://sanixdk.xyz/blogs/the-weird-concept-of-branchless-programming).

Via HN: https://news.ycombinator.com/item?id=45405750

#Optimization #Speed #Efficiency #BranchlessProgramming #Hardware #CPU #BranchPrediction

THE WEIRD CONCEPT OF BRANCHLESS PROGRAMMING

GeekProjects NewsJul 28, 2024
AMD Returns to 1996 With Zen 5’s Two-Block Ahead Branch Predictor https://hackaday.com/2024/07/28/amd-returns-to-1996-with-zen-5s-two-block-ahead-branch-predictor/ #branchprediction #Engineering #amd
AMD Returns To 1996 With Zen 5’s Two-Block Ahead Branch Predictor

An interesting finding in fields like computer science is that much of what is advertised as new and innovative was actually pilfered from old research papers submitted to ACM and others. Which is …

Hackaday
रञ्जित (Ranjit Mathew)Dec 27, 2021

"Beyond RISC - The Post-RISC Architecture" [1996], Brehob, et al (https://cse.msu.edu/~enbody/postrisc/postrisc2.htm).

Via HN: https://news.ycombinator.com/item?id=29659456

#RISC #PostRISC #ComputerArchitecture #SuperScalar #CPU #Pipeline #BranchPrediction #Hardware

postrisc2

रञ्जित (Ranjit Mathew)Dec 14, 2021

"Branch Prediction" [2017], Dan Luu (https://danluu.com/branch-prediction/).

On HN: https://news.ycombinator.com/item?id=15078574 and https://news.ycombinator.com/item?id=20324092

#CPU #Architecture #ComputerArchitecture #BranchPrediction #SuperScalar #Pipeline #Pipelining #Performance #Prediction #Hardware

Branch prediction

रञ्जित (Ranjit Mathew)May 7, 2021

Nice:

“Branch Predictor: How Many ‘If’s Are Too Many? Including x86 And M1 Benchmarks!”, Cloudflare (https://blog.cloudflare.com/branch-predictor/).

Via HN: https://news.ycombinator.com/item?id=27062650

#CPU #Hardware #Optimization #Performance #BranchPrediction #SpeculativeExecution #Intel #AMD #ARM #Pipeline

Branch predictor: How many "if"s are too many? Including x86 and M1 benchmarks!

Is it ok to have if clauses that will basically never be run? Surely, there must be some performance cost to that...

The Cloudflare Blog
Harald EilertsenMar 27, 2018
As predicted, more branch prediction processor attacks are discovered:

"Researchers from the College of William and Mary, Carnegie Mellon, the University of California Riverside, and Binghamton University have described a security attack that uses the speculative execution features of modern processors to leak sensitive information and undermine the security boundaries that operating systems and software erect to protect important data.

That probably sounds familiar."

https://quitter.no/url/1702276

#security #computers #cpu #branchprediction
As predicted, more branch prediction processor attacks are discovered

New attack focuses on a different part of the branch prediction system.