Re: XML was RE: [GD-General] RE: A portable preferences library

[Alen L. <ale...@cr...>]

> Well the engine IS loading uncompressed MB's. The decompression happens
> by another part
> of the loader so when I'm talking about load time performance I'm
> talking about the time to parse
> the UNCOMPRESSED file.

Please try to understand that I am not trying to bash you. I would like to
know the numbers. Those 16-20 seconds you gave is not a useable number,
because it is mixed with other preprocessing. And because unzipped file size
for XML is not very meaningless.

Hm. How can I explain this better? It doesn't matter how fast does it load in
terms of MB/s of some format that you use. What matters is how much useable
data per second can you load. Since we don't have any defined units for
"useable data", we can only compare that with some binary format. If you say
that XML size increase is neutralized by zipping, I would assume that you mean
that a zipped XML file would be of about same size as zipped binary file with
that same data in it. Now, the best way to judge the speed of XML parser would
then be to see how much _zipped_ MB/s can it load. If it is much below HDD
speed, then you cannot say that its costs are negligible.

Is that a more understandable explanation? And can you please give us that
info?

Thanks,
Alen



----- Original Message -----
From: "Jorrit Tyberghein" <Jor...@uz...>
To: <gam...@li...>
Sent: Tuesday, December 16, 2003 14:50
Subject: Re: XML was RE: [GD-General] RE: A portable preferences library


> Alen Ladavac wrote:
>
> >>The PlaneShift game (made with CS) has about 25 megabytes (uncompressed)
> >>of XML files (aggregated
> >>in four big files) of level data. On my Linux system at home (an Athlon
> >>XP2000) the levels load
> >>in about 16-20 seconds.
> >>
> >>
> >
> >There is a mistake in your reasoning, isn't it? You say that we shouldn't
look
> >at the size of the uncompressed XML data. Then you start profiling how many
> >uncompressed MB/s can you load.
> >
> Well the engine IS loading uncompressed MB's. The decompression happens
> by another part
> of the loader so when I'm talking about load time performance I'm
> talking about the time to parse
> the UNCOMPRESSED file.
>
> >You should look at the number of compressed
> >MB/s. If running from harddisk, you should be loading between 5-20MB/s
> >(depending on speed of the drive). Anything less than 5MB, and you are very
> >CPU limited. And you should _never_ be CPU limited while loading. Not even
> >close. If you are CPU limited on a 2GHz CPU, think about all the poor
700MHz
> >Celeron users trying to load your game. There is no excuse for loading data
at
> >less speed than the media can stream.
> >
> Yes they are. You have to process the data. You have to send textures to
> the hardware (which is
> something that you cannot do in load time). Note that binary dump of a
> structure is not possible
> in our situation since Crystal Space is portable and has to run on
> various operating systems and
> CPU architectures. So we cannot depend on binary data being compatible.
> That means there is
> always SOME processing.
>
> Greetings,
>
> > Think about whether your users like to
> >wait 20 seconds to load a level. If it could be loaded in 5, or even
less...
> >
> >Can you get some more accurate profile?
> >
> >Alen
> >
> >
> >
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