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From: Yury Norov <ynorov@caviumnetworks.com>
To: Adam Wallis <awallis@codeaurora.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Arnd Bergmann <arnd@arndb.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>, Ingo Molnar <mingo@redhat.com>,
	Jan Glauber <jglauber@cavium.com>,
	jason.low2@hp.com
Subject: Re: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks
Date: Thu, 13 Apr 2017 13:33:09 +0300	[thread overview]
Message-ID: <20170413103309.GA1875@yury-N73SV> (raw)
In-Reply-To: <a4f067df-4c22-5c90-d70a-809903c60296@codeaurora.org>

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

It sounds great. So performance issue is looking like my local
problem, most probably because I ran tests on Qemu VM.

I don't see any problems with this series, other than performance,
and if it looks fine now, I think it's good enough for upstream.

Yury.

WARNING: multiple messages have this Message-ID (diff)
From: ynorov@caviumnetworks.com (Yury Norov)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks
Date: Thu, 13 Apr 2017 13:33:09 +0300	[thread overview]
Message-ID: <20170413103309.GA1875@yury-N73SV> (raw)
In-Reply-To: <a4f067df-4c22-5c90-d70a-809903c60296@codeaurora.org>

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

It sounds great. So performance issue is looking like my local
problem, most probably because I ran tests on Qemu VM.

I don't see any problems with this series, other than performance,
and if it looks fine now, I think it's good enough for upstream.

Yury.

  reply	other threads:[~2017-04-13 10:33 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-10 21:35 [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Yury Norov
2017-04-10 21:35 ` Yury Norov
2017-04-10 21:35 ` [PATCH 1/3] kernel/locking: #include <asm/spinlock.h> in qrwlock.c Yury Norov
2017-04-10 21:35   ` Yury Norov
2017-04-10 21:35 ` [PATCH 2/3] asm-generic: don't #include <linux/atomic.h> in qspinlock_types.h Yury Norov
2017-04-10 21:35   ` Yury Norov
2017-04-10 21:35 ` [PATCH 3/3] arm64/locking: qspinlocks and qrwlocks support Yury Norov
2017-04-10 21:35   ` Yury Norov
2017-04-13 18:12   ` Peter Zijlstra
2017-04-13 18:12     ` Peter Zijlstra
2017-04-20 18:23     ` Yury Norov
2017-04-20 18:23       ` Yury Norov
2017-04-20 19:00       ` Mark Rutland
2017-04-20 19:00         ` Mark Rutland
2017-04-20 19:05       ` Peter Zijlstra
2017-04-20 19:05         ` Peter Zijlstra
2017-04-26 12:39         ` Yury Norov
2017-04-26 12:39           ` Yury Norov
2017-04-28 15:44           ` Will Deacon
2017-04-28 15:44             ` Will Deacon
2017-04-12 17:04 ` [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Adam Wallis
2017-04-12 17:04   ` Adam Wallis
2017-04-13 10:33   ` Yury Norov [this message]
2017-04-13 10:33     ` Yury Norov
2017-04-28 15:37     ` Will Deacon
2017-04-28 15:37       ` Will Deacon
2017-04-24 13:36   ` Will Deacon
2017-04-24 13:36     ` Will Deacon

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