RE: JFFS3 & performance

Joakim Tjernlund
2004-12-17T15:34:11Z

> Joakim Tjernlund wrote:
> >
> > 2) Consider another checksum algorithm. Crc32 is very expensive
> > and JFFS2 suffered severely in the early days. Now that crc32 is
> > very optimized that problem is less visible, but crc32 is still
> > expensive. Maybe an Adler32 checksum is good enough or a crc16?
>
> Does anyone have links to the profilling data that showed this?

I had long time ago. That was the reason I optimized the in kernel
crc32() function to its current status.

>
> (Also, I wouldn't have thought crc16 on 32 bit archs would have any
> significant performance benefits. But since I don't know either the
> crc16 or crc32 algorithms... *shrug*)

Well, benchmarking the crc32() and csum_partial() functions in the
kernel should give a clue.

Jocke