Difference between revisions of "Architecture/Proposal/Advanced Threading-Architecture"
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Type: Proposal | Type: Proposal | ||
+ | State: draft | ||
− | + | The advanced [[Uno/Term/Threading-Architecture|threading-architecture]] aims to solve OOos scalability and responsiveness problems. | |
− | + | ||
− | + | ==Problem== | |
− | + | A brief list of problems we face: | |
− | * unresponsive user interface | + | * Sometimes unresponsive user interface, e.g. trying to connect to a particular web server may take some minutes, without repaint and everything (it can take more time, if you have more than one http:// reference in your document) ;-). |
− | * busy waiting | + | * Polling / busy waiting, e.g. frequent re-schedule or yield calls, while loading or saving a document. |
− | * | + | * Scalability with multiple clients doing API calls, only one API call can be in execution at any time. |
− | * | + | * Most long lasting operations such as loading, saving, printing etc. are not interruptible. |
− | + | ==Solution== | |
OOo must be changed to be purely event / callback driven. Please see [[Wikipedia:|Wikipedia]] for what [[wikipedia:event-driven programming|event-driven programming]] is. | OOo must be changed to be purely event / callback driven. Please see [[Wikipedia:|Wikipedia]] for what [[wikipedia:event-driven programming|event-driven programming]] is. | ||
The following list gives a first idea, of what should be done, | The following list gives a first idea, of what should be done, | ||
− | * all (potentially) blocking calls need to be event driven, | + | * 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), | * 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, | + | * UNIX asynchronous signals, being an process interface by their own, 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. | ||
− | + | ===Pros=== | |
* Not calling potential blocking system calls leads to 'short' lasting mutex acquisitions. | * Not calling potential blocking system calls leads to 'short' lasting mutex acquisitions. | ||
* No hand crafted reschedules necessary anymore. | * No hand crafted reschedules necessary anymore. | ||
− | * Easy utilization of | + | * Easy utilization of hyper threading, multiple cores and SMP. |
− | * | + | * Controllable CPU utilization and possible avoidance of over utilization. |
* 'Simple' architecture. | * 'Simple' architecture. | ||
− | * | + | * Potentially high level thread abstraction. |
− | + | ===Cons=== | |
* (assumed to be) Hard to implement. | * (assumed to be) Hard to implement. | ||
Pseudo Code for event loop: | Pseudo Code for event loop: | ||
− | < | + | <source lang="cpp"> |
void dispatch(int signal) { | void dispatch(int signal) { | ||
switch(signal) { | switch(signal) { | ||
Line 60: | Line 59: | ||
return 0; | return 0; | ||
} | } | ||
− | </ | + | </source> |
Graphical overview:<br> | Graphical overview:<br> | ||
[[Image:Spec_Architecture_Threading_Advanced.jpg]] | [[Image:Spec_Architecture_Threading_Advanced.jpg]] | ||
− | [[Category | + | |
+ | [[Category:Architecture]] | ||
+ | [[Category:Draft]] | ||
+ | [[Category:Proposal]] | ||
+ | [[Category:Multi-Threading]] |
Latest revision as of 11:36, 5 May 2008
Type: Proposal State: draft
The advanced threading-architecture aims to solve OOos scalability and responsiveness problems.
Contents
Problem
A brief list of problems we face:
- Sometimes unresponsive user interface, e.g. trying to connect to a particular web server may take some minutes, without repaint and everything (it can take more time, if you have more than one http:// reference in your document) ;-).
- Polling / busy waiting, e.g. frequent re-schedule or yield calls, while loading or saving a document.
- Scalability with multiple clients doing API calls, only one API call can be in execution at any time.
- Most long lasting operations such as loading, saving, printing etc. are not interruptible.
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),
- UNIX asynchronous signals, being an process interface by their own, 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, multiple cores and SMP.
- Controllable CPU utilization and possible avoidance of over utilization.
- 'Simple' architecture.
- Potentially high level thread abstraction.
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; }