Re: Kernel Scalability

[l.genoni@oltrelinux.com]

On Wed, 2 May 2007, Daniel J Blueman wrote:

> Date: Wed, 2 May 2007 16:43:44 +0100
> From: Daniel J Blueman <daniel.blueman@gmail.com>
> To: Rajib Majumder <rajibm2005@gmail.com>
> Cc: Linux Kernel <linux-kernel@vger.kernel.org>
> Subject: Re: Kernel Scalability
> Resent-Date: Wed, 02 May 2007 17:44:58 +0200
> Resent-From: <l.genoni@sns.it>
> 
> On 2 May, 14:00, "Rajib Majumder" <rajibm2005@gmail.com> wrote:
>> Hi,
>> 
>> I am wondering if 2.4.x/2.6.x kernel is scalable enough to run on
>> 8-CPU hardware. Do we have any scalability comparison data between
>> 2.4/2.6 kernels and beyond 4-CPU?
>> 
>> If yes, is the scalablity is near linear?
>> 
>> Any input is appreciated.
>
> There are 128-processor IA64 systems which run recent 2.6 kernels out
> there; the per-processor counters, RCU and page-fault scalability work
> has been instrumental to the necessary scaling for decent resource
> usage on these.
>
> IIRC, there were some patches being developed to improve pagecache
> scalability lately too, but I guess it all depends on what kind of
> workload you have...
>
To stay on systems probably more familiar to the user who asked this 
question, there are also some 64 core X86_64 bot AMD and Intel out there, 
here the 2.6 kernel is doing 
very well even on those intel CPU with shared L2 cache.
I have some 16 and 32 core Opteron and never had scalability problems.
You have to pay a lot of attention to your kernel configuration  (100 HZ, 
just BKL preemption), and to the 
filesystems you decide to use.