Parallele Programmierung - FS18
Begriffe für Prüfung Parallele Programmierung ETH
Begriffe für Prüfung Parallele Programmierung ETH
Kartei Details
| Karten | 26 |
|---|---|
| Sprache | Deutsch |
| Kategorie | Informatik |
| Stufe | Universität |
| Erstellt / Aktualisiert | 20.08.2018 / 20.08.2018 |
| Lizenzierung | Keine Angabe |
| Weblink |
https://card2brain.ch/box/20180820_parallele_programmierung_fs18
|
| Einbinden |
<iframe src="https://card2brain.ch/box/20180820_parallele_programmierung_fs18/embed" width="780" height="150" scrolling="no" frameborder="0"></iframe>
|
Amdahl's law
Sp = 1/(f+(1-f)/p)
S: Speedup
p: n Processors
f = Anteil nicht parallelisierbarer Instruktionen
Gustafson's law
Sp = p + (p-1)f
S: Speedup
p: n Processors
f: sequential fraction of any parallel process
max Speedup (Amdahl)
Amdahl with p -> inf
Pipeline troughput (Durchsatz)
troughput = 1 / (max(computationtime(stages))
[ignoring lead-in and lead-out time]
Latency (Latenz)
time to perform a computation
balanced pipeline: constant over time
Lock Contention
If a thread wants to take a lock that is already taken by another thread
Solution: Back off if the lock cannot be taken
Mutex
Mutual Exclusion
Solutions for ABA-Problem
- DCAS
- Garbage Collection
- Pointer Tagging
- Hazard Pointers
- Transactional Memory
