Re: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks

From	Will Deacon <will.deacon@arm.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks
Date	2017-04-24 15:40 +0200
Message-ID	<tzMnD-7Bg-5@gated-at.bofh.it> (permalink)
References	<tvtWh-7dn-7@gated-at.bofh.it> <tvtWh-7dn-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Apr 12, 2017 at 01:04:55PM -0400, Adam Wallis wrote:
> On 4/10/2017 5:35 PM, Yury Norov wrote:
> > The patch of Jan Glauber enables queued spinlocks on arm64. I rebased it on
> > latest kernel sources, and added a couple of fixes to headers to apply it 
> > smoothly.
> > 
> > Though, locktourture test shows significant performance degradation in the
> > acquisition of rw-lock for read on qemu:
> > 
> >                           Before           After
> > spin_lock-torture:      38957034        37076367         -4.83
> > rw_lock-torture W:       5369471        18971957        253.33
> > rw_lock-torture R:       6413179         3668160        -42.80
> > 
> 
> On our 48 core QDF2400 part, I am seeing huge improvements with these patches on
> the torture tests. The improvements go up even further when I apply Jason Low's
> MCS Spinlock patch: https://lkml.org/lkml/2016/4/20/725

Does the QDF2400 implement the large system extensions? If so, how do the
queued lock implementations compare to the LSE-based ticket locks?

Will

Thread

Re: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Adam Wallis <awallis@codeaurora.org> - 2017-04-12 19:10 +0200
  Re: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Will Deacon <will.deacon@arm.com> - 2017-04-24 15:40 +0200
  Re: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Will Deacon <will.deacon@arm.com> - 2017-04-28 17:40 +0200

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