Difference between revisions of "Architecture/Proposal/Advanced Threading-Architecture"
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===Problem=== | ===Problem=== | ||
The following list gives a brief overview, of where the problems lie, | 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 more than one http:// reference in your document) ;-), | + | * 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), | * busy waiting (e.g. frequent re-schedule or yield calls), | ||
* scalability with multiple threads, in particular when doing API programming, | * scalability with multiple threads, in particular when doing API programming, | ||
− | * operations (e.g. loading, saving, printing etc.) are not interruptable. | + | * most long lasting operations (e.g. loading, saving, printing etc.) are not interruptable. |
===Solution=== | ===Solution=== |
Revision as of 14:29, 21 July 2006
State: draft Type: Proposal
Advanced OOo Threading Architecture
The advanced threading architecture aims to solve OOs multi threading and concurrency problems.
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.
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,
- 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:
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; }