[RC5] newbie question

Elektron elektron_rc5 at yahoo.ca
Tue Aug 26 05:30:20 EDT 2003


On Monday, Aug 25, 2003, at 23:46 Asia/Hong_Kong, Slawek wrote:

> Of course I could have missed something, so
> please tell me: why do you want to split them?

So you can narrow down the people (or blocks) who might have produced 
the error.

If the same (big) block is received from both 1 person, and 16 
different people, and the residual doesn't match, being able to split 
it is a good idea (and then you can almost totally rule out the 16 
people).

Concatenating it would work well enough (after all, 4 bytes isn't that 
much).

>> Another factor is that tracking the running
>> XOR/CRC/whatever may have a greater
>> impact on performance on register-starved
>> architectures (X86).
>
> It can be hold in memory and be cached.
>
> Of course using cache may or may not be desired.

Loading data from the L1 cache typically takes a clock cycle. Storing 
it takes another clock cycle. And if you have to swap it with something 
else, that's four clock cycles.

> This words about cache brings another question.
> Where d.net client slows down the system most
> and is it possible to reduce that effect?

The client uses (and touches) very little memory, IME. But when in 
doubt, touch less memory.

It might also be worthwhile to make the client mlock() (it doesn't seem 
to on OSX anyway).

- Purr



More information about the rc5 mailing list