linux-kernel - RE: [PATCH 00/13] lib/generic-radix-tree: genradix bug fix and optimisations.

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Message-ID: <17da427b99b444ce9d310d6542ae197e@AcuMS.aculab.com>
Date:   Tue, 25 Aug 2020 16:00:35 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Marcelo Ricardo Leitner' <marcelo.leitner@...il.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "'linux-sctp@...r.kernel.org'" <linux-sctp@...r.kernel.org>,
        Eric Biggers <ebiggers@...nel.org>,
        'Catalin Marinas' <catalin.marinas@....com>,
        "'kent.overstreet@...il.com'" <kent.overstreet@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        'Neil Horman' <nhorman@...driver.com>
Subject: RE: [PATCH 00/13] lib/generic-radix-tree: genradix bug fix and
 optimisations.

From: 'Marcelo Ricardo Leitner'
> Sent: 25 August 2020 16:41
> 
> On Tue, Aug 25, 2020 at 02:52:34PM +0000, David Laight wrote:
> > The genradix code is used by SCTP for accessing per-stream data.
> > This means there are quite a lot of lookups but the code wasn't
> > really optimised at all.
> 
> My test box is down for the moment and will bring it on later today or
> tomorrow, so I can't test it yet. What should we expect as performance
> gains here?

Not sure, probably not much, but it ought to show up :-)
There'll be bigger gains on a cpu that has software ilog2().

I've only checked SCTP still works.
I've requested 32k streams on a listener - to force a level-2 tree.
I've also done at least one check with a massive pad in the sctp
stream structure.

I ought to check one of my M3UA or M2PA 'double-reflect' loopback tests.

	David

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