Message-ID: <47E3B924.3000304@colorfullife.com>
Date: Fri, 21 Mar 2008 14:33:24 +0100
From: Manfred Spraul <manfred@colorfullife.com>
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To: Nadia Derbey <Nadia.Derbey@bull.net>
CC: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: Scalability requirements for sysv ipc
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Nadia Derbey wrote:
> Manfred Spraul wrote:
>>
>> A microbenchmark on a single-cpu system doesn't help much (except 
>> that 2.6.25 is around factor 2 slower for sysv msg ping-pong between 
>> two tasks compared to the numbers I remember from older kernels....)
>>
>
> If I remember well, at that time I had used ctxbench and I wrote some 
> other small scripts.
> And the results I had were around 2 or 3% slowdown, but I have to 
> confirm that by checking in my archives.
>
Do you have access to multi-core systems? The "best case" for the rcu 
code would be
- 8 or 16 cores
- one instance of ctxbench running on each core, bound to that core.

I'd expect a significant slowdown. The big question is if it matters.

--
    Manfred
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