Parallele Programmierung - FS18
Begriffe für Prüfung Parallele Programmierung ETH
Begriffe für Prüfung Parallele Programmierung ETH
Kartei Details
Karten | 26 |
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Sprache | Deutsch |
Kategorie | Informatik |
Stufe | Universität |
Erstellt / Aktualisiert | 20.08.2018 / 20.08.2018 |
Lizenzierung | Keine Angabe |
Weblink |
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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