Difference between revisions of "Architecture/Proposal/Advanced Threading-Architecture"
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− | The advanced threading architecture aims to solve OOs multi threading and concurrency problems. | + | The advanced [[Uno/Term/Threading-Architecture|threading-architecture]] aims to solve OOs multi-threading and concurrency problems. |
==Problem== | ==Problem== | ||
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* asynchronous signals need to be mapped to events, | * asynchronous signals need to be mapped to events, | ||
* Windows window messages need to be mapped to events, | * Windows window messages need to be mapped to events, | ||
− | * the threading architecture must be defined high level, e.g. | + | * the [[Uno/Term/Threading-Architecture|threading-architecture]] must be defined high level, e.g. |
** concurrency per application, or | ** concurrency per application, or | ||
** concurrency per document. | ** concurrency per document. |
Revision as of 08:08, 5 September 2006
Type: Proposal State: draft
The advanced threading-architecture aims to solve OOs multi-threading and concurrency problems.
Contents
Problem
The following list gives a brief overview, of where the problems lie,
- unresponsive user interface (e.g. trying to connect to a particular web server may take somes minutes, without repaint and everything (it can take more time, if you have more than one http:// reference in your document) ;-),
- busy waiting (e.g. frequent re-schedule or yield calls),
- scalability with multiple threads, in particular when doing API programming,
- most long lasting operations (e.g. loading, saving, printing etc.) are not interruptable.
Solution
OOo must be changed to be purely event / callback driven. Please see Wikipedia for what event-driven programming is.
The following list gives a first idea, of what should be done,
- all (potentially) blocking calls need to be event driven,
- all long lasting calls need to be executed by dedicated threads, notifying the consumers via events / callbacks, in case data is available (thus basically creating event sources and event sinks),
- asynchronous signals need to be mapped to events,
- Windows window messages need to be mapped to events,
- the threading-architecture must be defined high level, e.g.
- concurrency per application, or
- concurrency per document.
Pros
- Not calling potential blocking system calls leads to 'short' lasting mutex acquisitions.
- No hand crafted reschedules necessary anymore.
- Easy utilization of Hyper Threading, multi cores and SMP.
- Controlable CPU utilization and possible avoidance of over utilization.
- 'Simple' architecture.
- One single location where to create threads.
Cons
- (assumed to be) Hard to implement.
Pseudo Code for event loop:
[[cpp]
void dispatch(int signal) {
switch(signal) { case SIGIO: fileHandler(getHandle()); break; case SIGTERM: ... }
}
int quit; sigset_t sigset;
int main(void) {
int signal;
while(!quit) { sigwait(&sigset, &signal); dispatch(signal); }
return 0;
}