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Message-ID: <3FDFE95C.9050901@cyberone.com.au>
Date: Wed, 17 Dec 2003 16:27:56 +1100
From: Nick Piggin <piggin@cyberone.com.au>
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To: Ingo Molnar <mingo@redhat.com>
CC: linux-kernel <linux-kernel@vger.kernel.org>,
       William Lee Irwin III <wli@holomorphy.com>,
       Rusty Russell <rusty@rustcorp.com.au>,
       Anton Blanchard <anton@samba.org>,
       "Martin J. Bligh" <mbligh@aracnet.com>,
       "Nakajima, Jun" <jun.nakajima@intel.com>, Mark Wong <markw@osdl.org>
Subject: Re: [PATCH] improve rwsem scalability (was Re: [CFT][RFC] HT scheduler)
References: <20031208155904.GF19412@krispykreme> <3FD50456.3050003@cyberone.com.au> <20031209001412.GG19412@krispykreme> <3FD7F1B9.5080100@cyberone.com.au> <3FD81BA4.8070602@cyberone.com.au> <3FD8317B.4060207@cyberone.com.au> <20031211115222.GC8039@holomorphy.com> <3FD86C70.5000408@cyberone.com.au> <20031211132301.GD8039@holomorphy.com> <3FD8715F.9070304@cyberone.com.au> <20031211133207.GE8039@holomorphy.com> <3FD88D93.3000909@cyberone.com.au> <3FD91F5D.30005@cyberone.com.au> <Pine.LNX.4.58.0312120440400.14103@devserv.devel.redhat.com> <3FDA5842.9090109@cyberone.com.au> <3FDBB261.5010208@cyberone.com.au>
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Nick Piggin wrote:

>
>
> Nick Piggin wrote:
>
>>
>>
>>
>> The benchmark dies at 160 rooms unfortunately. Probably something in 
>> the JVM.
>>
>> I'll do a larger number of runs around the 130-150 mark.
>>
>
> OK, this is an average of 5 runs at 145, 150, 155 rooms with my scheduler
> patches, with and without my rwsem patch. Its all over the place, but 
> I think
> rwsem does give a small but significant improvement.
>
> http://www.kerneltrap.org/~npiggin/rwsem2.png


What do you think? Is there any other sorts of benchmarks I should try?
The improvement I think is significant, although volanomark is quite
erratic and doesn't show it well.

I don't see any problem with moving the wakeups out of the rwsem's spinlock.