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- Subject: RE: Performance
- From: Chris.Kaiser@...
- Date: Tue, 6 Nov 2001 12:12:19 -0800
Well, there was to be a background service monitoring the
db for changes to the rules, that would preform the compilation.
Then the resulting .dll would be pushed to a dir. There would
be a history of three dlls, and a periodic update of like 15 minutes.
So it wouldn't impact the clients. I was just hoping of outputing
lua script instead of the dlls.. but I guess, there would still be
unloading as you'd have to refresh the lua state?
Hmmm.. sorry for being only marginally on topic.
> -----Original Message-----
> From: Tom Wrensch [mailto:firstname.lastname@example.org]
> Sent: Tuesday, November 06, 2001 11:40 AM
> To: Multiple recipients of list
> Subject: Re: Performance
> > On Tue, Nov 06, 2001 at 10:47:08AM -0800,
> Chris.Kaiser@peoplefirst.com wrote:
> > > One good reason why, and one that I need, is to convince
> > > that its a worthy solution to some dynamic code
> generation problems.
> > >
> > > My boss wants me to generate compiled C++ on the fly based on the
> > > user communities mods.
> > Okay. I presume this is for performance reasons?
> > > We're to build a series of tools to enable the user community to
> > > change the business rules on the fly. I'd like for these
> rules to be
> > > generated in lua and parsed from our C++ engine. But I need to
> > > convince him that it will be fast enough.
> I did something similar to this for a large insurance
> company. We rolled
> our own language, a solution that made sense at the time. We
> would have
> saved a lot of time/effort if Lua had been available (this was 1993 or
> so). It has all the capabilities we needed and is much faster
> than our own
> solution. Certainly if I had to do it again I would use Lua.
> I certainly would never have recommended creating compiled
> modules in 'C'
> or some such language! Not only is it a much more difficult
> solution to
> implement (and a nightmare to debug and maintain), but the performance
> issues are incredibly complex. How large are these modules?
> How often are
> they loaded/reloaded? Do changes have to take effect
> dynamically? If so
> how will that be handed? What about the cost of recompilation, C++
> compilers are not exactly easy on the processor. If you wish
> I will state
> my reservations to your management officially. (I look good on paper).
> It may not relate, but when we rolled our own language at the
> company, we too were origionally worried about performance.
> As it turned
> out the performance issues were dominated by database access/data
> communication times -- CPU usage made almost zero difference. In this
> situation the compiled module solution would be SLOWER
> because the modules
> will almost certainly be larger than the equivalent Lua bytecodes.
> Sorry, this is only marginally on-topic.
> - Tom Wrensch