RE: JFFS3 & performance

Joakim Tjernlund
2004-12-22T15:31:02Z

> Here is backward engel32. It runs about 1.5% faster than forward
> engel32 in my hash test. Other backward algorithms should be in the
> same order (depending on hardware).

Hi again

Can you do
1) First run a forward and then a backward version on memory space >= 2*L1 cache
2) Then do two forward runs on the same memory.

Compare the delta between 1) and 2)
That should give a clue if it is worth having a backward version.

>
> Adler32 beats the hell out of every other algorithm. Except for the
> backwards part, it appears to be a clear winner.

Have you look at the assembler Engler32 generates? Every instruction counts
in such small loops.

Jocke

PS.
I am levaing for Christmas in 2 hours and will be offline more or less until January
so I guess I won't be much help in the near future.