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From: Richard Weinberger <richard@nod.at>
To: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>,
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Subject: Re: xxhash ?
Date: Thu, 28 Dec 2017 11:06:25 +0100
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Am Donnerstag, 28. Dezember 2017, 10:44:05 CET schrieb Joakim Tjernlund:
> On Thu, 2017-12-28 at 10:38 +0100, Richard Weinberger wrote:
> 
> > CAUTION: This email originated from outside of the organization. Do not
> > click links or open attachments unless you recognize the sender and know
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> > 
> > Joakim,
> > 
> > On Thu, Dec 28, 2017 at 7:13 AM, Joakim Tjernlund
> > <Joakim.Tjernlund@infinera.com> wrote:
> > 
> > > Now that xxhash is in the tree one could look at replacing
> > > crc32 in JFFS2/UBI. This would make checksumming much faster.
> > 
> > 
> > Since this will require a change of the on-disk format we have to be
> > very careful.
> > Do you have a use-case where crc32 is the bottle neck?
> 
> 
> Not directly, I remember the good old days when mounting took forever,
> mostly
 due to crc32. I then optimized crc32(the big tables you have today)
> and some other JFFS2 optimizations. Since crc32 is used everywhere in JFFS2
> I figure xxhash would help, especially on low end CPUs

Unless this gives a decent speedup I don't think we should add new features to 
JFFS2.
For UBI/UBIFS it is a different story. Did you also tests with UBI?

Thanks,
//richard