January 1998
- Mail from mud Zoran's final Imp Stephen Zepp
- Mail from mud Zoran's final Imp coder@ibm.net
- Mail from mud Zoran's final Imp Shawn Halpenny
- Mail from mud Zoran's final Imp JC Lawrence
- Mail from mud Zoran's final Imp Shawn Halpenny
- Happy new year Marian Griffith
- Totally OT... Marian Griffith
- Totally OT... (Or is it?) s001gmu@nova.wright.edu
- Mud-Dev FAQ Ling
- Mud-Dev FAQ Jon A. Lambert
- Mud-Dev FAQ JC Lawrence
- Mud-Dev FAQ Adam Wiggins
- Who's bugging who? : was- Wild West Jon A. Lambert
- my bio (was Mud-Dev FAQ) Mike Sellers
- request for comments (was: Mud-Dev FAQ) Vadim Tkachenko
- request for comments (was: Mud-Dev FAQ) Jon A. Lambert
- request for comments (was: Mud-Dev FAQ) coder@ibm.net
- request for comments (was: Mud-Dev FAQ) JC Lawrence
- request for comments (was: Mud-Dev FAQ) s001gmu@nova.wright.edu
On Mon, 5 Jan 1998, Vadim Tkachenko wrote:
>
>Jon A. Lambert wrote:
...
>> Variations on event-driven design
>
>Can you please elaborate on that?
I've spent the last month or so of my free time tossing around ideas for our
event driver, and I think I've finally settled on a general model. I have yet
to implement and test all of it, so I'm sure I'll be fine-tuning it, but here's
where it stands for the moment:
Definately Multi-threaded, though not as heavily as JC's model (so far).
I'm aiming for a statically sized pool of about 10 threads to handle events,
though that number is most certainly not set in stone.
All events are descended from a base event class, and the driver has
knowledge of only that base class. (A fundamental of OO design, but worth
stating.)
Pending events are stored in a queue wrapped in a pretty simple structure
containing a reference to the event object, an event ID, and the event's
timestamp (along with all the stuff necessary to make a doubly linked list).
Call it a Tuple if you like.
Each 'tick', all events scheduled to be handled are pulled off the main
queue into a secondary queue, where the thread pool attacks them (in no
guaranteed order), each thread grabbing an event and calling it's Handle
method. Threads go back to sleep once all events in the secondary queue
have been handled.
I will most likely use a locked model for access to the DB, but I need to
do a bit -o- research and thinking before I commit to one model or the other.
The main design concerns I dealt with in comming to the decisions I've made:
How many threads, executing potentially I/O intensive DB Queries, can run
simultaineously w/o bogging down the server? This is obviously tied to
the machine/os/thread implementation/DB version the end design is run on,
but for my sanity I decided on a static pool, with a boot-time configurable
number of threads. heck, I could prolly pretty easily add a command to
allow admin to add some threads to the pool on the fly, but I prefer to
minimize the cost of thread creation, localizing it to a boot-time expense.
For the lockless v. locked model, my main concern was/is how many threads,
executing at the same tick, are going to be handling events targeting the
same data? I figgure there won't be too many events executed simultaineously
that target the same data. It will happen, there's no doubt about that, but
I feel the majority of events (executing at the same tick) will be aimed at
different targets. This assumption may well be proven wrong, but for now I
can only go with it and see what happens. :) If it proves to be the case
that a large enough % of the events target the same data, I may adopt some
schemes to try and shuffle events targeting the same data into the same
threads, so they are executed sequentially by that thread, removing the
issue.
My reasoning is that, combined with ballancing the number of threads
correctly, this will allow the overhead of locking data to be outweighed
by the preformance gain of multithreading. Too much locking, and the
threads execute in series, loosing all preformance increase, too few
threads, and locking overhead outweighs performance gain.
Current, unanswered questions:
What happens if it takes more than one tick to process all the events in
the secondary queue? This says either that there are not enough threads to
process all the events quickly enough, or that there are too many events! :)
I'm thinking I'll just put the events in the same secondary queue, and have
the threads do a bit of prioritizing... only if there are no threads
executing events for the previous tick will they start processing the new
tick's events... dunno. I need to think about it some more. :)
I haven't spent much time on gracefull shut-down of the queue, or storing of
the event list to rebuild a queue, but they are next on the hit parade.
Did I miss anything glaring? :)
-Greg - request for comments (was: Mud-Dev FAQ) JC Lawrence
- request for comments (was: Mud-Dev FAQ) Vadim Tkachenko
- OT: Suomi Finland Ola Fosheim Grøstad
- OT: Suomi Finland ##Make Nylander
- Totally OT... (Or is it?) (yes it is ;) Marian Griffith
- Totally OT... (Or is it?) (yes it is ;) Ola Fosheim Grøstad
- Totally OT... (Or is it?) (yes it is ;) Adam Wiggins
- Totally OT... (Or is it?) (yes it is ;) Ola Fosheim Grøstad
- Totally OT... (Or is it?) (yes it is ;) Jon A. Lambert
- Totally OT... (Or is it?) (yes it is ;) Ola Fosheim Grøstad
- Totally OT... (Or is it?) (yes it is ;) JC Lawrence
- Totally OT... (Or is it?) (yes it is ;) Jon A. Lambert
- Totally OT... (Or is it?) (yes it is ;) Mike Sellers
- Totally OT... (Or is it?) (yes it is ;) JC Lawrence
- Totally OT... (Or is it?) (yes it is ;) JC Lawrence
- Journal of MUD Research, Vol. 3, No. 1 [TEXT] coder@ibm.net
- World Seeding (was Task Parsing) Ling
- World Seeding (was Task Parsing) JC Lawrence
- World Seeding (was Task Parsing) Stephen Zepp
- threaded servers (was request for comments Mike Sellers
- MUD Economy Shawn Halpenny
- MUD Economy Adam Wiggins
- MUD Economy Shawn Halpenny
- MUD Economy Ling
- MUD Economy Brandon J. Rickman
- MUD Economy Marian Griffith
- MUD Economy Shawn Halpenny
- MUD Economy Shawn Halpenny
- MUD Economy JC Lawrence
- MUD Economy Koster, Raph
- MUD Economy Matt Chatterley
- MUD Economy JC Lawrence
- MUD Economy Jon A. Lambert
- OT: Jobs available Koster, Raph
- OT: DCOM and RMI Jon A. Lambert
- OT: DCOM and RMI Vadim Tkachenko
- OT: DCOM and RMI Vadim Tkachenko
- OT: DCOM and RMI Miroslav Silovic
- OT: DCOM and RMI Alex Oren
- OT: DCOM and RMI Chris Gray
- request for comments Miroslav Silovic
- request for comments JC Lawrence
- Event handling (was: request for comments) Vadim Tkachenko
- Event handling (was: request for comments) s001gmu@nova.wright.edu
- Event handling (was: request for comments) Vadim Tkachenko
- Event handling (was: request for comments) s001gmu@nova.wright.edu
- Event handling (was: request for comments) Vadim Tkachenko
- Event handling (was: request for comments) JC Lawrence
- Event handling (was: request for comments) s001gmu@nova.wright.edu
- Event handling (was: request for comments) JC Lawrence
- Event handling (was: request for comments) s001gmu@nova.wright.edu
- Event handling (was: request for comments) JC Lawrence
- Event handling (was: request for comments) Matt Chatterley
- Event handling (was: request for comments) s001gmu@nova.wright.edu
- Event handling (was: request for comments) s001gmu@nova.wright.edu
- Event handling (was: request for comments) JC Lawrence
- Event handling (was: request for comments) Vadim Tkachenko
- request for comments JC Lawrence
- Text vs Video; Movies, Books & muds. Nathan Yospe
- Unique items (was: Graphic MUDS/Ultima Online) Vadim Tkachenko
- Unique items (was: Graphic MUDS/Ultima Online) JC Lawrence
- Unique items (was: Graphic MUDS/Ultima Online) Brandon J. Rickman
- Unique items (was: Graphic MUDS/Ultima Online) Adam Wiggins
- Unique items (was: Graphic MUDS/Ultima Online) Brandon J. Rickman
- Unique items (was: Graphic MUDS/Ultima Online) Marian Griffith
- Unique items (was: Graphic MUDS/Ultima Online) coder@ibm.net
- Unique items (was: Graphic MUDS/Ultima Online) coder@ibm.net
- Unique items (was: Graphic MUDS/Ultima Online) Chris Gray
- Unique items (was: Graphic MUDS/Ultima Online) coder@ibm.net
- Unique items (was: Graphic MUDS/Ultima Online) coder@ibm.net
- Unique items (was: Graphic MUDS/Ultima Online) coder@ibm.net
- Unique items (was: Graphic MUDS/Ultima Online) Adam Wiggins
- Unique items (was: Graphic MUDS/Ultima Online) coder@ibm.net
- Delivery Notification: Delivery has failed PMDF e-Mail Interconnect
- Unique items Richard Woolcock
- Unique items Jon A. Lambert
- Unique items Vadim Tkachenko
- Unique items Jon A. Lambert
- Unique items JC Lawrence
- Delivery Notification: Delivery has failed PMDF e-Mail Interconnect
- Delivery Notification: Delivery has failed PMDF e-Mail Interconnect
- Delivery Notification: Delivery has failed PMDF e-Mail Interconnect
- Two Tiers Ling
- MUD Development Digest Dr. Cat
- FAQ Ling
- Clients Matt Chatterley
- Clients JC Lawrence
- Clients Shawn Halpenny
- Clients Matt Chatterley
- Event handling - some definitions Jon A. Lambert
- Event Handling Jon A. Lambert
- Simulations - was: 'A flamewar startingpoint.' Jon A. Lambert
- Formatting apology Stephen Zepp
- OT: Insane Wordwrapping Caliban Tiresias Darklock
- OT: Insane Wordwrapping Alex Oren
- Summary Marian Griffith
- Clients Andrew Wilson
- Vast areas in muds Ling
- Vast areas in muds John G.
- Vast areas in muds Nathan Yospe
- Vast areas in muds Mike Sellers
- Vast areas in muds John G.
- Vast areas in muds Nathan Yospe
- META: Web futures for the list JC Lawrence
- OT: Socket programming - platform specific Jon A. Lambert
- OT: Socket programming - platform specific Chris Gray
- OT: Socket programming - platform specific Jon A. Lambert
- OT: Socket programming - platform specific Caliban Tiresias Darklock
- OT: Socket programming - platform specific Chris Gray
- Graphical mud perspectives Richard Woolcock
- Graphical mud perspectives Nathan Yospe
- Graphical mud perspectives Richard Woolcock
- Graphical mud perspectives Koster, Raph
- Graphical mud perspectives Mike Sellers
- Graphical mud perspectives Koster, Raph
- CORBA, RMI, threads Marc Eyrignoux
- CORBA, RMI, threads Nathan Yospe
- CORBA, RMI, threads Marc Eyrignoux
- CORBA, RMI, threads s001gmu@nova.wright.edu
- CORBA, RMI, threads Brandon Gillespie
- CORBA, RMI, threads Chris Gray
- CORBA, RMI, threads Marc Eyrignoux
- CORBA, RMI, threads Brandon Gillespie
- CORBA, RMI, threads s001gmu@nova.wright.edu
- CORBA, RMI, threads coder@ibm.net
- CORBA, RMI, threads s001gmu@nova.wright.edu
- CORBA, RMI, threads Vadim Tkachenko
- CORBA, RMI, threads Caliban Tiresias Darklock
- CORBA, RMI, threads coder@ibm.net
- Clients based on Netscape 5? Greg Munt
- Clients based on Netscape 5? Chris Gray
- Clients based on Netscape 5? Caliban Tiresias Darklock
- Clients based on Netscape 5? Vadim Tkachenko
- Clients based on Netscape 5? Caliban Tiresias Darklock
- Clients based on Netscape 5? Chris Gray
- Clients based on Netscape 5? Vadim Tkachenko
- Clients based on Netscape 5? Chris Gray
- Clients based on Netscape 5? Vadim Tkachenko
- Clients based on Netscape 5? Chris Gray
- Clients based on Netscape 5? Marian Griffith
- Clients based on Netscape 5? coder@ibm.net
- OT? The impact of the web on muds Mike Sellers
- The Anti-Mac Interface JC Lawrence
- 3D graphics (Was: The impact of the web on muds) Jon Leonard
- 3D graphics (Was: The impact of the web on muds) Caliban Tiresias Darklock
- 3D graphics (Was: The impact of the web on muds) coder@ibm.net
- 3D graphics (Was: The impact of the web on muds) Mike Sellers
- 3D graphics (Was: The impact of the web on muds) Chris Gray
- 3D graphics (Was: The impact of the web on muds) Caliban Tiresias Darklock
- 3D graphics (Was: The impact of the web on muds) coder@ibm.net
- 3D graphics (Was: The impact of the web on muds) coder@ibm.net
- VRML Becomes ISO/IEC International Standard (fwd) Nathan Yospe
- Arctic's Project? Brandon Cline
- Arctic's Project? Adam Wiggins
- Arctic's Project? Brandon Cline
- Arctic's Project? Chris Gray
- FAQ Marc Eyrignoux
- Java and Javascript Greg Munt
- Java and Javascript Chris Gray
- Java and Javascript Matt Chatterley
- Java and Javascript coder@ibm.net
- Java and Javascript Matt Chatterley
- Java and Javascript Caliban Tiresias Darklock
- Java and Javascript Matt Chatterley
- Java and Javascript Caliban Tiresias Darklock
- Java and Javascript Chris Gray
- Java and Javascript Jon Leonard
- Java and Javascript Matt Chatterley
- Java and Javascript Jon A. Lambert
- Java and Javascript Ben Greear
- Java and Javascript Jon A. Lambert
- Java and Javascript Ben Greear
- Java and Javascript Jon A. Lambert
- Java and Javascript Ben Greear
- Java and Javascript Jon A. Lambert
- Java and Javascript Mike Sellers
- Java and Javascript J C Lawrence
- Java and Javascript Caliban Tiresias Darklock
- Java and Javascript Jon A. Lambert
- Java and Javascript Caliban Tiresias Darklock
- Java and Javascript Jon A. Lambert
- Java and Javascript Caliban Tiresias Darklock
- Java and Javascript Jon A. Lambert
- Java and Javascript Caliban Tiresias Darklock
- Java and Javascript Travis Casey
- Java and Javascript Jon A. Lambert
- Java and Javascript Sauron
- Java and Javascript Jon A. Lambert
- Java and Javascript Caliban Tiresias Darklock
- Java and Javascript Alex Oren
- Java and Javascript Chris Gray
- Java and Javascript coder@ibm.net
- Java and Javascript Matt Chatterley
- Java and Javascript coder@ibm.net
- MetaVoice, MetaFont Ling
- MetaVoice, MetaFont Richard Woolcock
- MetaVoice, MetaFont Vadim Tkachenko
- MetaVoice, MetaFont JC Lawrence
- MetaVoice, MetaFont Chris Gray
- The MLI Project Vadim Tkachenko
- The MLI Project Marc Eyrignoux
- The MLI Project Vadim Tkachenko
- The MLI Project coder@ibm.net
- The MLI Project Ling
- The MLI Project coder@ibm.net
- The MLI Project Caliban Tiresias Darklock
- The MLI Project Travis Casey
- The MLI Project Travis Casey
- The MLI Project coder@ibm.net
- The MLI Project s001gmu@nova.wright.edu
- The MLI Project Vadim Tkachenko
- The MLI Project Travis Casey
- The MLI Project Stephen Zepp
- The MLI Project coder@ibm.net
- The MLI Project Travis Casey
- The MLI Project Chris Gray
- The MLI Project Ling
- The MLI Project Andrew C.M. McClintock
- The MLI Project Ling
- The MLI Project Chris Gray
- The MLI Project Caliban Tiresias Darklock
- The MLI Project Chris Gray
- The MLI Project Caliban Tiresias Darklock
- The MLI Project Niklas Elmqvist
- The MLI Project Caliban Tiresias Darklock
- The MLI Project Chris Gray
- The MLI Project Ling
- The MLI Project Caliban Tiresias Darklock
- The MLI Project J C Lawrence
- The MLI Project Chris Gray
- The MLI Project Koster, Raph
- The MLI Project J C Lawrence
- The MLI Project Vadim Tkachenko
- Races and stuff (was: FAQ) Vadim Tkachenko
- Races and stuff (was: FAQ) Marc Eyrignoux
- Races and stuff (was: FAQ) Vadim Tkachenko
- OT: I'm moving again! JC Lawrence
- MUD Development Digest Dr. Cat
- Administrative Responsibilities Greg Munt
- Administrative Responsibilities Jon A. Lambert
- Administrative Responsibilities Greg Munt
- Administrative Responsibilities Jon A. Lambert
- Administrative Responsibilities Mike Sellers
- Administrative Responsibilities Chris Gray
- Administrative Responsibilities Greg Munt
- Administrative Responsibilities coder@ibm.net
- Administrative Responsibilities Jon A. Lambert
- Administrative Responsibilities Greg Munt
- Administrative Responsibilities Jon A. Lambert
- Administrative Responsibilities coder@ibm.net
- Administrative Responsibilities Chris Gray
- Administrative Responsibilities Mike Sellers
- Administrative Responsibilities Mike Sellers
- Administrative Responsibilities Adam Wiggins
- Administrative Responsibilities Greg Munt