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Date: Sun, 25 Mar 2001 19:00:59 +0200
From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Mitchell Blank Jr <mitch@sfgoth.com>
Cc: Wichert Akkerman <wichert@cistron.nl>, linux-kernel@vger.kernel.org
Subject: Re: Larger dev_t
Message-ID: <20010325190059.B16840@pcep-jamie.cern.ch>
In-Reply-To: <UTC200103251231.OAA10795.aeb@vlet.cwi.nl> <99l375$rn5$1@picard.cistron.nl> <20010325081524.E30469@sfgoth.com>
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Mitchell Blank Jr wrote:
> Wichert Akkerman wrote:
> > You are just delaying the problem then, at some point your uptime will
> > be large enough that you have run through all 64bit pids for example.
> 
> 64 bits is enough to fork 1 million processes per second for over
> 500,000 years.  I think that's putting the problem off far enough.

The year is 2006.  IBM's latest supercluster has 1000 boxes, each with 4
x 8-way SMT processors running at 1THz.  Dense optical interconnect
provides NUMA-style cache coherency, and the entire system runs like a
giant SMP box (using kernel data structure replication).  Each active
thread is able to clone() 500,000,000 threads per second, in a pid space
shared throughout the cluster.

A virus arrives containing while(1){clone();}

Engineers observe pid wraparound approximately 2 weeks later :-)

-- Jamie
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