Re: [Lcd4linux-devel] Dynamic loading of drivers / plugins ?

[<Mar...@t-...>]

On Wed, 14 Jan 2004 11:05:59 +0100
Michael Reinelt <re...@eu...> wrote:

> [hashes]

> Sorry. Marksu, are you listening? Are you subscribed to lcd4linux-devel?
 
Yes.  

> The reason for hashes is the following:
> 
> Say you write a plugin which returns values from /proc/cpuinfo. There 
> are values like "CPU MHz" or "BogoMips". You get these values by reading 
> and parsing /proc/cpuinfo.
> 
> Now if the plugin is asked for "MHz", it doesn't know that a few 
> microseconds later a call for "BogoMips" will happen. Therefore for 
> every call, the whole file would be parsed.
> 
> If you use a hash, you fill up the hash with all values from 
> /proc/cpuinfo when parsing it. Subsequent calls would not parse the file 
> again, but read the values from the hash.
> 
> You have to use something like a "timeout", and remember the time when 
> the contents of the file was last read. If the timeout is over, you have 
> to read and parse the file again.
> 
> SOme file change very seldom (/proc/cpuinfo probably changes never), 
> others change quite regular. But you can save a lot of CPU if you define 
> a timeout of, say, 100 msec.
> 
Great Michael! I will check out the CVS today.
Maybe that tommorow the XMMS-Plugin will use the HASH Function.
I will work on it.

Markus Keil

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Saxony, Germany