Topic: concurrency

topics > computer science > Group: parallel processing

asynchronous processing
communicating sequential processes
concurrency control by monitors
concurrency control by sequencers
concurrent operations
concurrent while in parallel processing
coordination system
critical regions
lock-free concurrency
managing shared memory
non-deterministic processing
optimistic update for concurrency control
parallel control statements
Petri net
proving concurrent programs
synchronized processing
Subtopic: concurrent events up

Quote: events are concurrent if they occur closer together than can be resolved in the system [»reedDP2_1979]
Quote: two occurrences are concurrent if they are not ordered in an occurrence graph [»holtAW9_1968]
Quote: two events are concurrent if neither happened before the other; can not effect each other [»lampL7_1978]
Quote: two actions are simultaneous if their durations overlap [»gottA4_1983, OK]
Quote: Petri nets feature proper concurrency; i.e., the priority of causality over temporal order, and partial independence [»petrCA_1996]
Quote: a temporal relationship defines a partial ordering; events are concurrent if they are unordered [»holtAW_1970]
Quote: while concurrent occurrences are at the same time, the time window increases with the distance between them in system space [»holtAW3_1979]
Quote: concurrency expresses a lack of those constraints that communication produces; due to spatial separation of intercommunicating actors [»holtAW8_1977c]
Quote: simultaneous, independent events execute in an unpredictable order [»handP_1981]
Quote: space and time must be interlocked because simultaneous events are relative; 'now' is inconsistent at a distance [»feynR_1965]

Subtopic: no global properties up

Quote: with concurrency, do not have the notion of system state; might ask how far out-of-step can things be [»holtAW_1970]
Quote: in process paradigm there is no global state or global time due to concurrent activity [»stroR10_1986]
Quote: Petri net theory rejects all global properties [»petrCA1_1966]
Quote: to describe complex systems need to represent the concurrent holdings of many conditions [»holtAW_1970]

Subtopic: coincidence up

Quote: coincidence in a system occurs when one transition always occurs with another; e.g., enter a train as leave the platform [»holtAW3_1979]
Quote: coincident transitions imply that two roles interact in a common activity; the transitions express the same fact [»holtAW3_1979]

Subtopic: locking, concurrency control up

Quote: review of concurrency control; locking, restart, two phase, optimistic methods [»thomA3_1998]
Quote: review concurrency control methods with reduced lock contention, indices, aggregate data, transactions, relaxed queries
Quote: for concurrency, locking data is more fundamental than multi-tasking [»stroB_1994]
Quote: use destructors to release a lock for exclusive access to data; simpler, more reliable, handles exceptions

Subtopic: concurrent language up

Quote: use predicate transition nets for modeling concurrency; use regular expressions to model sequential behavior
Quote: for a language, define a functional subset without side effects; can be executed concurrently [»giffDK7_1985, OK]
Quote: avoid timing-dependent behavior if all processes are data driven by messages received from one sender and processed in order [»dennPJ_1980]
Quote: in Thoth and V, messages are for communication and processes are for concurrency [»cherDR4_1984]

Subtopic: identity up

Quote: the key idea of pi-calculus is naming or reference; concurrency requires the independent identity of its components [»milnR1_1993]

Subtopic: concurrency bugs up

Quote: the most common synchronization error was ignoring read synchronization; data may be out-of-date or uninitialized [»hoveD7_2004]
Quote: binary operations on shared objects must synchronize both objects; all threads must use the same lock acquisition order [»hoveD7_2004]
Quote: concurrency bug patterns: mismatched wait, double locking, notify vs. notifyAll, run vs. start, mutable lock, naked notify, spin wait [»hoveD7_2004]

Subtopic: problems of concurrency up

Quote: systems for concurrent programming fail to handle complex, concurrent subtasks in a nondeterministic world [»donnMD_1987]
Quote: with complex, concurrent subtasks, must search for appropriate reactions to unpredictable events
Quote: many operating systems will crash and require a complete restart; often due to incorrect coordination of concurrent activity; better now [»dennPJ_1980]
Quote: instead of one person, one computer, follow one task, one computer; avoids crashes [»dvorJC9_1989]
Quote: production systems provide too much concurrency; serial behavior is difficult to do

Related Topics up

Topic: asynchronous processing (30 items)
Topic: communicating sequential processes (33 items)
Topic: concurrency control by monitors (24 items)
Topic: concurrency control by sequencers (27 items)
Topic: concurrent operations (22 items)
Topic: concurrent while in parallel processing (5 items)
Group: coordination system   (8 topics, 217 quotes)
Topic: critical regions (58 items)
Topic: lock-free concurrency (8 items)
Topic: managing shared memory (74 items)
Topic: non-deterministic processing (19 items)
Topic: optimistic update for concurrency control (35 items)
Topic: parallel control statements (12 items)
Topic: Petri net (44 items)
Topic: proving concurrent programs (37 items)
Topic: synchronized processing (35 items)
Topic: time
(49 items)

Updated barberCB 2/06
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